1. CERTIFICATE OF SERVICE
      1. Table 4-1 Potential Emissions Reductions from RICE 26
      2. Table 4-2 Potential Emissions Reductions from Turbines 26
      3. Table 5-1 Cost Effectiveness for Retrofit of Various NOx Control Systems 28
        1. Figure 2-1 Figure 2-2
        2. PM2.5 Nonattainment Areas 8-Hour Ozone Nonattainment Areas
        3. Table 3-1
        4. Table 4-1
        5. Potential Emissions Reductions from Reciprocating I. C. Engines7
      4. Air/Fuel Ratio Adjustment
      5. Ignition Timing Retard
      6. Low Emission Combustion
        1. Table 4-2
        2. Potential Emissions Reductions from Turbines7
          1. Engine Size
      7. A/F + Electronic Ignition to Lean-Burn SI Engine

BEFORE THE ILLINOIS POLLUTION CONTROL BOARD
IN THE MATTER OF:
)
)
SECTION 27 PROPOSED RULES FOR
)
NITROGEN OXIDE (NO
x
) EMISSIONS
)
R07-19
FROM STATIONARY RECIPROCATING
)
(Rulemaking – Air)
INTERNAL COMBUSTION ENGINES AND
)
TURBINES: AMENDMENTS TO 35 ILL.
)
ADM. CODE PARTS 211 AND 217
)
NOTICE
TO:
John Therriault, Assistant Clerk
Illinois Pollution Control Board
State of Illinois Center
100 West Randolph, Suite 11-500
Chicago, Illinois 60601
SEE ATTACHED SERVICE LIST
PLEASE TAKE NOTICE that I have today filed with the Office of the Pollution Control Board
the attached MOTION TO PROCEED WITH AMENDED PROPOSAL AND WITHDRAW
TESTIMONY of the Illinois Environmental Protection Agency a copy of which is herewith
served upon you.
ILLINOIS ENVIRONMENTAL PROTECTION
AGENCY
By: ___/s/___________________
Rachel L. Doctors
Assistant Counsel
Division of Legal Counsel
DATED: December 20, 2007
P.O. Box 19276
Springfield, Illinois 62794-9276
217.782-5544
217.782.9143 (TDD)
Electronic Filing - Received, Clerk's Office, December 20, 2007

BEFORE THE ILLINOIS POLLUTION CONTROL BOARD
IN THE MATTER OF:
)
)
SECTION 27 PROPOSED RULES FOR
)
NITROGEN OXIDE (NO
x
) EMISSIONS
)
R07-19
FROM STATIONARY RECIPROCATING
)
(Rulemaking – Air)
INTERNAL COMBUSTION ENGINES AND
)
TURBINES: AMENDMENTS TO 35 ILL.
)
ADM. CODE SECTION 201.146
)
AND PART 217
)
MOTION TO PROCEED WITH AMENDED PROPOSAL
AND WITHDRAW TESTIMONY
NOW COMES the Illinois Environmental Protection Agency (“Illinois EPA”), by one of
its attorneys and, pursuant to 35 Ill. Adm. Code 101.502 and 102.402, moves, with the
clarifications explained below, that the Hearing Officer proceed with scheduling hearings on the
above rulemaking. Proceeding with R07-19 will, in part, satisfy Illinois’ obligation to meet the
Clean Air Act’s (“CAA”) requirement under the 8-hour National Ambient Air Quality Standard
(“NAAQS”) for nitrogen oxides (“NO
x
”) reasonably available control technology (“RACT”) and
would further improve air quality with respect to particulate mater by reducing the precursors for
fine particulate (“PM
2.5
”). The Illinois EPA also moves that testimony submitted prior to the
Illinois Pollution Control Board’s (“Board”) split of the original docket be withdrawn. In
support of its Motion, the Illinois EPA respectfully states as follows:
1.
On March 29, 2007, the Illinois EPA filed a proposal to control NO
x
from engines
and turbines statewide. Its proposal included statewide NO
x
emissions control requirements
based on the capacity of the engine or turbine, as well as any engine that had been identified by
the United States Environmental Protection Agency (“USEPA”) as a large engine under the NO
x
State Implementation Plan (“SIP”) Call.
Electronic Filing - Received, Clerk's Office, December 20, 2007

2.
On May 17, 2007, the Board bifurcated the proceeding into two dockets: R07-18
(NO
x
SIP Call engines) and R07-19 (engines and turbines statewide). The entire original
proposal, R07-18, went to First Notice on May 4, 2007. 31 Ill. Reg. 6597. On June 8, 2007, the
new docket for engines and turbines statewide, R07-19, went to First Notice. 31 Ill. Reg. 7702.
3.
On August 23, 2007, the Illinois EPA filed a Motion requesting that R07-19 be
held until new modeling based on a revised emissions inventory was completed and the results of
such modeling were shared with the interested parties to this rulemaking. This Motion was
granted on August 27, 2007.
4.
On September 20, 2007, the Board fully adopted R07-18. The present rulemaking
docket would amend 35 Ill. Adm. Code 217, Subpart Q, but would not change the substantive
elements as they apply to NO
x
SIP Call engines.
5.
On October 4, 2007, the Illinois EPA shared the new modeling results with
interested parties. Based on the results of the new modeling, and in light of the adoption of
docket R07-18, the Illinois EPA has determined that proceeding with this rulemaking in the
context of the present docket would best serve all parties in terms of expeditiously achieving a
final rulemaking to address sources that remain of concern. Therefore, the Illinois EPA’s plan is
to continue controlling NO
x
emissions from engines listed in Appendix G (as adopted in R07-
18), and to propose to control NO
x
emissions from engines and turbines located at 100 ton per
year sources (“RACT units”) in either the greater Chicago nonattainment or Metro-East/St. Louis
nonattainment areas based on the originally proposed capacity thresholds.
1
1
The greater Chicago nonattainment area, for purposes of the 8-hour ozone and PM
2.5
NAAQS, consists of the
following counties and partial counties: Cook, DuPage, Grundy (Aux Sable and Goose Lake Townships only),
Kane, Kendall (Oswego Township only), Lake, McHenry, and Will. The Metro-East/St. Louis 8-hour ozone
nonattainment area consists of the following counties: Jersey, Madison, Monroe, and St. Clair. For purses of PM
2.5
, the Metro-East/St. Louis nonattainment area consists of the following counties and partial counties: Madison,
Monroe, Randolph (Baldwin Township only) and St. Clair. For the purposes of this proposal, a combined 8-hour
Electronic Filing - Received, Clerk's Office, December 20, 2007

6.
The attached draft of the proposed regulations (Att. A) differs from the version
published on May 4, 2007, as follows:
a)
Control requirements are limited to engines or turbines located at a 100
ton per year source in the Greater Chicago or Metro-East/St. Louis areas
with a capacity of 500 bhp or 3.5 MW, respectively;
b)
A new compliance date of May 1, 2010, for RACT units has been added;
c)
The exemption for Subpart W units is being deleted because the
requirements for the Clean Air Interstate Rule that replaces those
requirements is not equivalent to RACT;
d)
Two additions to the emissions averaging plan compliance option have
been added. First, sources that contain RACT units in addition to engines
and turbines may include the engines and turbines in an emissions
averaging plan adopted to address these other types of RACT units.
Second, owners or operators with affected engines and turbines located at
more than one source within a given nonattainment area may develop a
companywide emissions averaging plan for the given nonattainment area;
e)
A clarification has been made that testing and monitoring do not apply to
low usage units; and
f)
The definition for emergency/standby unit is being amended to allow for
50 hours of nonemergency use. This change is consistent with a similar
definition that applies to maximum achievable control technology units.
7.
The Illinois EPA is filing an amended Technical Support Document (“TSD”) that
reflects changes in the items listed below and is requesting that the TSD filed with the original
proposal (R07-18) be withdrawn from the docket. While the Illinois EPA is not filing an
amended Statement of Reasons, it requests that where the items listed below are discussed in that
document, and differ from the discussion in the amended TSD, the facts in the amended TSD
should be the facts relied upon.
a)
Geographic scope of the amended proposal is now limited to the greater
Chicago and Metro-East/St. Louis areas;
PM
2.5
nonattainment area is being proposed for applicability of Jersey, Madison, Monroe, Randolph (Baldwin
Township only) and St. Clair Counties.
Electronic Filing - Received, Clerk's Office, December 20, 2007

b)
A smaller emissions inventory is now included;
c)
Fewer emissions reductions and lower costs are projected, as fewer units
are subject to control requirements;
d)
RACT is not necessarily required for PM
2.5
nonattainment areas; and
e)
USEPA adopted final guidance for implementing the PM
2.5
NAAQS. This
replaces ref. 29 in the original TSD, and is numbered 5 in the amended
TSD. (Att. F).
8.
The purpose of this motion is to provide the Board and all interested parties with
all requisite revised or substituted language to adapt docket R07-19 as was “created” by the
Board to fit the Illinois EPA’s current approach. Attached to this motion are amended regulatory
language based on Subpart Q as adopted in R07-18 (Att. A), an amended TSD (Att. B),
economic and budgetary forms for Parts 201, 211, and 217 (Atts. C, D and E), and a new TSD
reference 5 (an update of old Ref. 29) (Att. F). The amended language includes the clarifications
discussed in paragraph 6 above. Attachment A was shared with interested parties on December 2,
2007.
9.
The compliance date and averaging provisions are consistent with the Illinois
EPA’s plans with respect to control of other NO
x
RACT sources. Illinois is required under the
CAA to implement NO
x
RACT for 8-hour ozone in 2009. The Illinois EPA is proposing to give
sources more time to implement this requirement, as the rule is not yet adopted.
10.
The Illinois EPA requests that a conference call be held with the interested parties
and the Hearing Officer to determine convenient hearing dates for R07-19.
11.
The Illinois EPA requests that all the testimony submitted in support of the
original proposal (R07-18) on May 11, 2007, and subsequently included by the Board on the
docket for this rulemaking, be withdrawn as the basis and scope of this regulatory proposal is
significantly narrower with the adoption of R07-18 and the limited geographic applicability. The
Electronic Filing - Received, Clerk's Office, December 20, 2007

Illinois EPA only plans to have two witnesses testify at hearing in this rulemaking proceeding.
The Illinois EPA suggests that it be allowed to submit prefiled testimony 14 days before a
scheduled hearing. The Illinois EPA’s witnesses, Yoginder Mahajan and Robert Kaleel, would
be available for direct testimony and questioning.
WHERFORE, for the reasons stated above, the Illinois EPA respectfully requests that the
Hearing Officer grant the Illinois EPA’s Motion to Proceed with an Amended Proposal and
Withdraw Testimony.
Respectfully submitted,
ILLINOIS ENVIRONMENTAL
PROTECTION AGENCY
By:
___/s/__________________
Rachel L. Doctors
Assistant Counsel
Air Regulatory Unit
Division of Legal Counsel
DATED: December 20, 2007
1021 North Grand Avenue, East
P.O. Box 19276
Springfield, Illinois 62794-9276
217.782.5544
217.782.9143 (TDD)
217.782.9807 (Fax)
Electronic Filing - Received, Clerk's Office, December 20, 2007

 
BEFORE THE ILLINOIS POLLUTION CONTROL BOARD
STATE OF ILLINOIS
)
)
SS
COUNTY OF SANGAMON
)
)
CERTIFICATE OF SERVICE
I, the undersigned, an attorney, state that I have served electronically the attached
MOTION TO PROCEED WITH AMENDED PROPOSAL AND WITHDRAW TESTIMONY
of the Illinois Environmental Protection Agency upon the following persons:
John Therriault, Assistant Clerk
Illinois Pollution Control Board
State of Illinois Center
100 West Randolph, Suite 11-500
Chicago, Illinois 60601
SEE ATTACHED SERVICE LIST
and by electronic service from Springfield, Illinois on December 20, 2007.
ILLINOIS ENVIRONMENTAL
PROTECTION AGENCY
___/s/__________________
Rachel L. Doctors
Assistant Counsel
Air Regulatory Unit
Division of Legal Counsel
Dated: December 20, 2007
1021 North Grand Avenue East
Springfield, Illinois 62794-9276
(217) 782-5544
217.782.9143 (TDD)
Electronic Filing - Received, Clerk's Office, December 20, 2007

R07-19 Service List
Timothy Fox, Hearing Officer
Illinois Pollution Control Board
State of Illinois Center
100 W. Randolph, Suite 11-500
Chicago, IL 60601
Katherine D. Hodge
N. LaDonna Driver
Gale W. Newton
Hodge Dwyer Zeman
3150 Roland Ave.
PO Box 5776
Springfield, IL 62705-5776
N. LaDonna Driver
Illinois Environmental Regulatory Group
3150 Roland Ave.
Springfield, IL 62705-5776
Kathleen C. Bassi
Renee Cipriano
Joshua R. More
Stephen J. Bonebrake
Schiff Hardin, LLP
6600 Sears Tower
233 S. Wacker Drive
Chicago, IL 60606-6473
Electronic Filing - Received, Clerk's Office, December 20, 2007

SUBPART Q: STATIONARY RECIPROC
R07-19
ATING INTERNAL COMBUSTION ENGINES
AND TURBINES
Section 217.386
Applicability
a)
The provisions of this Subpart shall apply to all:
1)
A stationary Stationary reciprocating internal combustion engines engine
listed in Appendix G of this Part is subject to the requirements of this
Subpart Q.
2)
Stationary reciprocating internal combustion engines and turbines located
at a source that emits or has the potential it emit NO
x
in an amount equal
to or greater than 100 tons per year and is in either the area composed of
the Chicago area counties of Cook, DuPage, Kane, Lake, McHenry, and
Will, the Townships of Aux Sable and Goose Lake in Grundy County, and
the Township of Oswego in Kendall County, or in the area composed of
the Metro-East counties of Jersey, Madison, Monroe, and St. Clair, and
the Township of Baldwin in Randolph County, where:
A)
The engine at nameplate capacity is rated at equal to or greater
than 500 bhp output; or
B)
The turbine is rated at equal to or greater than 3.5 MW (4,694 bhp)
output at 14.7 psia, 59ºF and 60 percent relative humidity.
b)
Notwithstanding subsection (a) of this Section, an affected unit is not subject to
the requirements of this Subpart Q if the engine or turbine is or has been:
1)
Used as an emergency or standby unit as defined by 35 Ill. Adm. Code
211.1920;
2)
Used for research or for the purposes of performance verification or
testing;
3)
Used to control emissions from landfills, where at least 50 percent of the
heat input is gas collected from a landfill;
4)
Used for agricultural purposes including the raising of crops or livestock
that are produced on site, but not for associated businesses like packing
operations, sale of equipment or repair; or
5)
An engine with nameplate capacity rated at less than 1,500 bhp (1,118kW)
output, mounted on a chassis or skids, designed to be moveable, and
moved to a different source at least once every 12 months;
Electronic Filing - Received, Clerk's Office, December 20, 2007

12/20/2007 4:17 PM
Page
2
c)
If an exempt unit ceases to fulfill the criteria specified in subsection (b) of this
Section, the owner or operator must notify the Agency in writing within 30 days
after becoming aware that the exemption no longer applies and comply with the
control requirements of this Subpart Q.
d)
The requirements of this Subpart Q will continue to apply to any engine or turbine
that has ever been subject to the control requirements of Section 217.388, even if
the affected unit or source ceases to fulfill the rating requirements of subsection
(a) of this Section or becomes eligible for an exemption pursuant to subsection (b)
of this Section.
(Source: Amended at
Ill. Reg.
, effective
)
Section 217.388
Control and Maintenance Requirements
On and after the applicable compliance date in Section 217.392, an owner or operator of an
affected unit must inspect and maintain affected units as required by subsection (c) of this
Section and comply with either the applicable emissions concentration as set forth in subsection
(a) of this Section, or the requirements for an emissions averaging plan as specified in subsection
(b) of this Section, or the requirements for operation as a low usage unit as specified in
subsection (d) of this Section.
a)
The owner or operator must limits the discharge from an affected unit into the
atmosphere of any gases that contain NO
x
to no more than:
1)
150 ppmv (corrected to 15 percent O
2
on a dry basis) for spark-ignited
rich-burn engines;
2)
210 ppmv (corrected to 15 percent O
2
on a dry basis) for spark-ignited
lean-burn engines, except for existing spark-ignited Worthington engines
that are not listed in Appendix G;
3)
365 ppmv (corrected to 15 percent O
2
on a dry basis) for existing spark-
ignited Worthington engines that are not listed in Appendix G;
4)
660 ppmv (corrected to 15 percent O
2
on a dry basis) for diesel engines;
5)
42 ppmv (corrected to 15 percent O
2
on a dry basis) for gaseous fuel-fired
turbines; and
6)
96 ppmv (corrected to 15 percent O
2
on a dry basis) for liquid fuel-fired
turbines.
b)
The owner or operator must
compliesy with an emissions averaging plan as
Electronic Filing - Received, Clerk's Office, December 20, 2007

12/20/2007 4:17 PM
Page
3
provided for in either subsection (b)(1) or (b)(2) of this Section:
1)
For any affected unit identified by Section 217.386: The the requirements
of the applicable emissions averaging plan as set forth in Section 217.390;
or
2)
For units identified in Section 217.386(a)(2): The requirements of an
emissions averaging plan adopted pursuant to any other Subpart of this
Part. For such affected engines and turbines the applicable requirements
of this Subpart apply, including but not limited to, calculation of NO
x
allowable and actual emissions rates, compliance dates, monitoring,
testing, reporting, and recordkeeping.
c)
The owner or operator operates the affected unit as a low usage unit pursuant to
subsection (c)(1) or (c)(2) of this Section. Low usage units are not subject to the
requirements of this Subpart Q except for the requirements to inspect and
maintain the unit pursuant to subsection (d) of this Section, and retain records
pursuant to Sections 217.396(b) and (d). Either the limitation in subsection (c)(1)
or (c)(2) may be utilized at a source, but not both:
1)
The potential to emit (PTE) is no more than 100 TPY NO
x
aggregated
from all engines and turbines located at the source that are not otherwise
exempt pursuant to Section 217.386(b), and not complying with the
requirements of subsection (a) or (b) of this Section, and the NO
x
PTE
limit is contained in a federally enforceable permit; or
2)
The aggregate bhp-hrs/MW-hrs from all affected units located at the
source that are not exempt pursuant to Section 217.386(b), and not
complying with the requirements of subsection (a) or (b) of this Section,
are less than or equal to the bhp-hrs and MW-hrs operation limit listed in
subsection (c)(2)(A) and (c)(2)(B) of this Section. For units that drive a
natural gas compressor station but that are not located at a natural gas
compressor station or storage facility, the operation limits of subsection
(c)(2)(A) and (c)(2)(B) of this Section must be contained in a federally
enforceable permit. The operation limits are:
A)
8 mm bhp-hrs or less on an annual basis for engines; and
B)
20,000 MW-hrs or less on an annual basis for turbines.
d)
The owner or operator must inspects and performs periodic maintenance on the
affected unit, in accordance with a Maintenance Plan that documents:
1)
For a unit not located at natural gas transmission compressor station or
storage facility either:
Electronic Filing - Received, Clerk's Office, December 20, 2007

12/20/2007 4:17 PM
Page
4
A)
The manufacturer’s recommended inspection and maintenance of
the applicable air pollution control equipment, monitoring device,
and affected unit; or
B)
If the original equipment manual is not available or substantial
modifications have been made that require an alternative procedure
for the applicable air pollution control device, monitoring device,
or affected unit, the owner or operator must establish a plan for
inspection and maintenance in accordance with what is customary
for the type of air pollution control equipment, monitoring device,
and affected unit.
2)
For a unit located at a natural gas compressor station or storage facility,
the operator’s maintenance procedures for the applicable air pollution
control device, monitoring device, and affected unit.
(Source: Amended at
Ill. Reg.
, effective
)
Section 217.390
Emissions Averaging Plans
a)
An owner or operator of certain affected units may comply through an emissions
averaging plan.
1)
The unit or units that commenced operation before January 1, 2002, may
be included in only onean emissions averaging plan, as follows:
A)
The theunits:
i)
Listed in Appendix G and located at a single source or at
multiple sources in Illinois, so long as the units are owned
by the same company or parent company where the parent
company has working control through stock ownership of
its subsidiary corporations. A unit may be listed in only
one emissions averaging plan; or
ii)
Identified in Section 217.386(b)(2), and located at a single
source or at multiple sources in either the Chicago area
counties or Metro-East area counties, so long as the units
are owned by the same company or parent company where
the parent company has working control through stock
ownership of its subsidiary corporations.
B)
Units that have a compliance date later than the control period for
which the averaging plan is being used for compliance; and
Electronic Filing - Received, Clerk's Office, December 20, 2007

12/20/2007 4:17 PM
Page
5
C)
Units which the owner or operator may claim as exempt pursuant
to Section 217.386(b) but does not claim as exempt. For as long as
such unit is included in an emissions averaging plan, it will be
treated as an affected unit and subject to the applicable emission
concentration, limits, testing, monitoring, recordkeeping and
reporting requirements.
2)
The following types of units may not be included in an emissions
averaging plan:
A)
Units units that commence operation after January 1, 2002, unless
the unit replaces an engine or turbine that commenced operation on
or before January 1, 2002, or it replaces an engine or turbine that
replaced a unit that commenced operation on or before January 1,
2002. The new unit must be used for the same purpose as the
replacement unit. The owner or operator of a unit that is shutdown
and replaced must comply with the provisions of Section
217.396(c)(3) before the replacement unit may be included in an
emissions averaging plan.
B)
Units which the owner or operator is claiming are exempt pursuant
to Section 217.386(b) or as low usage units pursuant to Section
217.388(c).
b)
An owner or operator must submit an emissions averaging plan to the Agency by
the applicable compliance date set forth in Section 217.392. The plan must
include, but is not limited to:
1)
The list of affected units included in the plan by unit identification number
and permit number.
2)
A sample calculation demonstrating compliance using the methodology
provided in subsection (f) of this Section for both the ozone season and
calendar year.
c)
An owner or operator may amend an emissions averaging plan only once per
calendar year. An amended plan must be submitted to the Agency by May 1 of
the applicable calendar year. If an amended plan is not received by the Agency
by May 1 of the applicable calendar year, the previous year’s plan will be the
applicable emissions averaging plan.
d)
Notwithstanding subsection (c) of this Section, an owner or operator, and the
buyer, if applicable:
, must
Electronic Filing - Received, Clerk's Office, December 20, 2007

1)
Must submit an updated emissions averaging plan or plans to the Agency
within 60 days, if a unit that is listed in an emissions averaging plan is
sold or taken out of service.
2)
May amend its emissions averaging plan to include another unit within 30
days of discovering that the unit no longer qualifies as an exempt unit
pursuant to Section 217.386(b) or as a low usage unit pursuant to Section
217.388(c).
e)
An owner or operator must:
1)
Demonstrate compliance for both the ozone season (May 1 through
September 30) and the calendar year (January 1 through December 31) by
using the methodology and the units listed in the most recent emissions
averaging plan submitted to the Agency pursuant to subsection (b), (c), or
(d) of this Section; the higher of the monitoring or test data determined
pursuant to Section 217.394; and the actual hours of operation for the
applicable control period;
2)
Notify the Agency by October 31 following the ozone season, if
compliance cannot be demonstrated for that ozone season; and
3)
Submit to the Agency by January 31 following each calendar year, a
compliance report containing the information required by Section
217.396(c)(4).
f)
The total mass of actual NO
x
emissions from the units listed in the emissions
averaging plan must be equal to or less than the total mass of allowable NO
x
emissions for those units for both the ozone season and calendar year. The
following equation must be used to determine compliance:
N
act
N
all
Where:
N
act
=
=
n
i1
EM
act(i)
N
all
=
=
n
i1
EM
all(i)
N
act
=
Total sum of the actual NO
x
mass emissions from
units included in the averaging plan for each fuel used (lbs
per ozone season and calendar year).
N
all
=
Total sum of the allowable NO
x
mass emissions from units
included in the averaging plan for each fuel used (lbs per
ozone season and calendar year).
12/20/2007 4:17 PM
Page
6
Electronic Filing - Received, Clerk's Office, December 20, 2007

EM
all(i)
=
Total mass of allowable NO
x
emissions in lbs for a unit as
determined in subsection (g)(2) or (h)(2) of this Section.
EM
act(i)
=
Total mass of actual NO
x
emissions in lbs for a unit
as determined in subsection (g)(1) or (h)(1) of this Section.
i
=
Subscript denoting an individual unit and fuel used.
n
=
Number of different units in the averaging plan.
g)
For each unit in the averaging plan, and each fuel used by a unit, determine actual
and allowable NO
x
emissions using the following equations, except as provided
for in subsection (h) of this Section:
1)
Actual emissions must be determined as follows:
EM
act(i)
=
E
act(i)
x H
i
m
20.9 %O
C
xF x
20.9
E
m
j 1
2d(j)
d(act( j))
d
act(i)
=
=
2)
Allowable emissions must be determined as follows:
EM
all(i)
=
E
all(i)
x H
i
m
20.9 %O
C
xF x
20.9
E
m
j 1
2d(j)
d(all)
d
all(i)
=
=
Where:
EM
act(i)
=
Total mass of actual NO
x
emissions in lbs for a unit, except
as provided for in subsections (g)(3) and (g)(5) of this
Section.
EM
all(i)
=
Total mass of allowable NO
x
emissions in lbs for a unit,
except as provided for in subsection (g)(3) of this Section.
E
act
=
Actual NO
x
emission rate (lbs/mmBtu) calculated
according to the above equation.
E
all
=
Allowable NO
x
emission rate (lbs/mmBtu)
calculated according to the above equation.
H
=
Heat input (mmBtu/ozone season or mmBtu/year)
calculated from fuel flow meter and the heating
value of the fuel used.
C
d(act)
=
Actual concentration of NO
x
in lb/dscf (ppmv x
1.194 x 10
-7
) on a dry basis for the fuel used. Actual
concentration is determined on each of the most recent test
12/20/2007 4:17 PM
Page
7
Electronic Filing - Received, Clerk's Office, December 20, 2007

12/20/2007 4:17 PM
Page
8
run or monitoring pass performed pursuant to Section
217.394, whichever is higher.
C
d(all)
=
Allowable concentration of NO
x
in lb/dscf (allowable
emission limit in ppmv specified in Section 217.388(a),
except as provided for in subsection (g)(4), (g)(5), or (g)(6)
of this Section, if applicable.,(multiplied by 1.194 x 10
-7
)
on a dry basis for the fuel used.
F
d
=
The ratio of the gas volume of the products of combustion
to the heat content of the fuel (dscf/mmBtu) as given in the
table of F Factors included in 40 CFR 60, Appendix A,
Method 19 or as determined using 40 CFR 60, Appendix
A, Method 19.
%O
2d
=
Concentration of oxygen in effluent gas stream measured
on a dry basis during each of the applicable test or
monitoring runs used for determining emissions, as
represented by a whole number percent, e.g., for 18.7%O
2d
,
18.7 would be used.
i
=
Subscript denoting an individual unit and the fuel used.
j
=
Subscript denoting each test run or monitoring pass for an
affected unit for a given fuel.
m
=
The number of test runs or monitoring passes for an
affected unit using a given fuel.
3)
For a replacement unit that is electric-powered, the allowable NO
x
emissions from the affected unit that was replaced should be used in the
averaging calculations and the actual NO
x
emissions for the electric-
powered replacement unit (EM
(i)act elec
) are zero. Allowable NO
x
emissions for the electric-powered replacement are calculated using the
actual total bhp-hrs generated by the electric-powered replacement unit on
an ozone season and on an annual basis multiplied by the allowable NO
x
emission rate in lb/bhp-hr of the replaced unit. The allowable mass of
NO
x
emissions from an electric-powered replacement unit (EM
(i)all elec
)
must be determined by multiplying the nameplate capacity of the unit by
the hours operated during the ozone season or annually and the allowable
NO
x
emission rate of the replaced unit (E
all rep
) in lb/mmBtu converted to
lb/bhp-hr. For this calculation the following equation should be used:
EM
all elec(i)
= bhp x OP x F x E
all rep(i)
Where:
EM
all elec(i)
=
Mass of allowable NO
x
emissions from the electric-
powered replacement unit in pounds per ozone season or
calendar year.
bhp
=
Nameplate capacity of the electric-powered
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9
replacement unit in brake-horsepower.
OP
=
Operating hours during the ozone season or calendar
year.
F
=
Conversion factor of 0.0077 mmBtu/bhp-hr.
E
all rep(i)
=
Allowable NO
X
emission rate (lbs/mmBtu) of the replaced
unit.
i
=
Subscript denoting an individual electric unit and the fuel
used.
4)
For a replacement unit that is not electric, the allowable NO
x
emissions
rate used in the above equations set forth in subsection (g)(2) of this
Section must be the higher of the actual NO
x
emissions as determined by
testing or monitoring data or the applicable uncontrolled NO
x
emissions
factor from Compilation of Air pollutant emission Factors: AP-42,
Volume I: Stationary Point and Area Sources, as incorporated by reference
in Section 217.104 for the unit that was replaced.
5)
For a unit that is replaced with purchased power, the allowable NO
x
emissions rate used in the above equations set forth in subsection (g)(2) of
this Section must be the emissions concentration as set forth in Section
217.388(a) or subsection (g)(6) of this Section, when applicable, for the
type of unit that was replaced. For owners or operators replacing units
with purchased power, the annual hours of operations that must be used
are the calendar year hours of operation for the unit that was shutdown
averaged over the three-year period prior to the shutdown. The actual
NO
x
emissions for the units replaced by purchased power (EM
(i)act
) are
zero. These units may be included in any emissions averaging plan for no
more than five years beginning with the calendar year that the replaced
unit is shut down.
6)
For units that have a later compliance datenon-Appendix G units used in
an emissions averaging plan, allowable emissions rate used in the above
equations set forth in subsection (g)(2) of this Section must be:
A)
Prior to the applicable compliance date pursuant to Section
217.392, the higher of the actual NO
x
emissions as determined by
testing or monitoring data, or the applicable uncontrolled NO
x
emissions factor from Compilation of Air Pollutant Emission
Factors: AP-42, Volume I: Stationary Point and Areas Sources, as
incorporated by reference in Section 217.104); or
B)
On and after the unit’s applicable compliance date pursuant to
section 217.392, the applicable emissions concentration for that
type of unit pursuant to Section 217.388(a).
Electronic Filing - Received, Clerk's Office, December 20, 2007

h)
For units that use CEMS the data must show that the total mass of actual NO
x
emissions determined pursuant to subsection (h)(1) of this Section is less than or
equal to the allowable NO
x
emissions calculated in accordance with the equations
in subsections (f) and (h)(2) of this Section for both the ozone season and
calendar year. The equations in subsection (g) of this Section will not apply.
1)
The total mass of actual NO
x
emissions in lbs for a unit (EM
act
) must be
the sum of the total mass of actual NO
x
emissions from each affected unit
using CEMS data collected in accordance with 40 CFR 60 or 75, or
alternate methodology that has been approved by the Agency or USEPA
and included in a federally enforceable permit.
2)
The allowable NO
x
emissions must be determined as follows:
=
=
m
i
EM
all
i
Cd
i
flow
i
x
1
7
(
( )
)
(
*
*1.194 10 )
Where:
EM
all(i)
=
Total mass of allowable NO
x
emissions in lbs for a unit.
fFlow
i
=
Stack flow (dscf/hr) for a given stack.
Cd
i
=
Allowable concentration of NO
x
(ppmv) specified in
Section 217.388(a) of this subpart for a given stack. (1.194
x 10
-7
) converts to lb/dscf).
j
=
subscript denoting each hour operation of a given unit.
m
=
Total number of hours of operation of a unit.
i
=
Subscript denoting an individual unit and the fuel used.
(Source: Amended at
Ill. Reg.
, effective
)
Section 217.392
Compliance
a)
On and after January 1, 2008, an owner or operator of an affected engine listed in
Appendix G may not operate the affected engine unless the requirements of this
Subpart Q are met.
b)
On and after May 1, 2010, an owner or operator of a unit identified by Section
217.386(b)(2), and that is not listed in Appendix G, may not operate the affected
unit unless the requirements of this Subpart Q are met or the affected unit is
exempt pursuant to Section 217.386(b).
c)
Owners and operators of an affected unit may use NO
x
allowances to meet the
compliance requirements in Section 217.388 as specified below. A NO
x
allowance is defined as an allowance used to meet the requirements of a NO
x
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10
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11
trading program administered by USEPA where one allowance is equal to one ton
of NO
x
emissions.
1)
NO
x
allowances may be used only under the following circumstances:
A)
An anomalous or unforeseen operating scenario inconsistent with
historical operations for a particular ozone season or calendar year
that causes an exceedance of an emissions or operation hour
limitation;
B)
To achieve compliance no more than two events in any rolling
five-year period; and
C)
For a unit that is not listed in Appendix G.
2)
The owner or operator of the affected unit must surrender to the Agency a
NO
x
allowance for each ton or portion of a ton of NO
x
by which actual
emissions exceed allowed emissions. Where a low usage limitation under
Section 217.388(c)(2) has been exceeded, the owner or operator of the
affected unit must calculate the NO
x
emissions resulting from the number
of hours that exceeded the operating hour low usage limit and surrender to
the Agency one NO
x
allowance for each ton or portion of a ton of NO
x
that was calculated. For noncompliance with a seasonal limit in Section
217.388(b), only a NO
x
ozone season allowance must be used. For
noncompliance with the emissions concentration limits in Section
217.388(a), low usage limitations in Section 217.388(c) or an annual
limitation in an emissions averaging plan in Section 217.388(b), only a
NO
x
annual allowance may be used.
3)
The owner operator must submit a report documenting the circumstances
that required the use of NO
x
allowances and identify what actions will be
taken in subsequent years to address these circumstances and must transfer
the NO
x
allowances to the Agency’s federal NO
x
retirement account. The
report and the transfer of allowances must be submitted by October 31 for
exceedances during the ozone season and March 1 for exceedances of the
emissions concentration limits, the annual emissions averaging plan limits,
or low usage limitations. The report must contain the NATS serial
numbers of the NO
x
allowances.
(Source: Amended at
Ill. Reg.
, effective
)
Section 217.394
Testing and Monitoring
a)
An owner or operator must conduct an initial performance test pursuant to
subsection (c)(1) or (c)(2) of this Section as follows:
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1)
By January 1, 2008, for affected engines listed in Appendix G.
Performance tests must be conducted on units listed in Appendix G, even
if the unit is included in an emissions averaging plan pursuant to Section
217.388(b).
2)
By the applicable compliance date as set forth in Section 217.392, or
withinWithin the first 876 hours of operation per calendar year, which
ever is later:
A). Performance tests must be conducted on For affected units not listed
in Appendix G that operate more than 876 hours per calendar year;
and
B)
For units that are not affected units that are included in an
emissions averaging plan and operate more than 876 hours per
calendar year.
3)
Once within the five-year period after the applicable compliance date as
set forth in Section 217.392:
A)
For affected units that operate fewer than 876 hours per calendar
year; and. Performance tests must be conducted on
B)
For units that are not affected units that are included in an
emissions averaging plan and that operate fewer than 876 hours
per calendar year.
b)
An owner or operator of an engine or turbine must conduct subsequent
performance tests pursuant to subsection (c)(1), or (c)(2), or (c)(3) of this Section
as follows:
1)
For affected engines listed in Appendix G and all units included in an
emissions averaging plan, once every five years. Testing must be
performed in the calendar year by May 1 or within 60 days after starting
operation, whichever is later;
2)
If the monitored data shows that the unit is not in compliance with the
applicable emissions concentration or emissions averaging plan, the owner
or operator must report the deviation to the Agency in writing within 30
days and conduct a performance test pursuant to subsection (c) of this
Section within 90 days of the determination of noncompliance; and
3)
When in the opinion of the Agency or USEPA, it is necessary to conduct
testing to demonstrate compliance with Section 217.388, the owner or
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13
operator of a unit must, at his or her own expense, conduct the test in
accordance with the applicable test methods and procedures specified in
this Section within 90 days after receipt of a notice to test from the
Agency or USEPA.
c)
Testing Procedures:
1)
For an engine: The owner or operator must conduct a performance test
using Method 7 or 7E of 40 CFR 60, appendix A, as incorporated by
reference in Section 217.104. Each compliance test must consist of three
separate runs, each lasting a minimum of 60 minutes. NO
x
emissions must
be measured while the affected unit is operating at peak load. If the unit
combusts more than one type of fuel (gaseous or liquid) including backup
fuels, a separate performance test is required for each fuel.
2)
For a turbine included in an emissions averaging plan: The owner or
operator must conduct a performance test using the applicable procedures
and methods in 40 CFR 60.4400, as incorporated by reference in Section
217.104.
d)
Monitoring: Except for those years in which a performance test is conducted
pursuant to subsection (a) or (b) of this Section, the owner or operator of an
affected unit or a unit included in an emissions averaging plan must monitor NO
x
concentrations annually, once between January 1 and May 1 or within the first
876 hours of operation per calendar year, whichever is later. If annual operation
is less than 876 hours per calendar year, each affected unit must be monitored at
least once every five years. Monitoring must be performed as follows:
1)
A portable NO
x
monitor utilizing method ASTM D6522-00, as
incorporated by reference in Section 217.104, or a method approved by
the Agency must be used. If the engine or turbine combusts both liquid
and gaseous fuels as primary or backup fuels, separate monitoring is
required for each fuel.
2)
NO
x
and O
2
concentrations measurements must be taken three times for a
duration of at least 20 minutes. Monitoring must be done at highest
achievable load. The concentrations from the three monitoring runs must
be averaged to determine whether the affected unit is in compliance with
the applicable emissions concentration or emissions averaging plan as
specified in Section 217.388.
e)
Instead of complying with the requirements of subsections (a), (b), (c) and (d) of
this Section, an owner or operator may install and operate a CEMS on an affected
unit that meets the applicable requirements of 40 CFR 60, subpart A, and
appendix B, incorporated by reference in Section 217.104, and complies with the
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14
quality assurance procedures specified in 40 CFR 60, appendix F, or 40 CFR 75
as incorporated by reference in Section 217.104, or an alternate procedure as
approved by the Agency or USEPA in a federally enforceable permit. The CEMS
must be used to demonstrate compliance with the applicable emissions
concentration or emissions averaging plan only on an ozone season and annual
basis.
f)
The testing and monitoring requirements of this Section do not apply to affected
units in compliance with the requirements of the low usage limitations pursuant to
Section 217.388(c) or low usage units using NO
x
allowances to comply with the
requirements of this Subpart pursuant to Section 217.392(c). Notwithstanding the
above circumstances, when in the opinion of the Agency or USEPA, it is
necessary to conduct testing to demonstrate compliance with Section 217.388, the
owner or operator of a unit must, at his or her own expense, conduct the test in
accordance with the applicable test methods and procedures specified in this
Section within 90 days after receipt of a notice to test from the Agency or
USEPA.
(Source: Amended at
Ill. Reg.
, effective
)
Section 217.396
Recordkeeping and Reporting
a)
Recordkeeping. The owner or operator of a unit included in an emissions
averaging plan or an affected unit that is not exempt pursuant to Section
217.386(b) and is not subject to a the low usage exemption of Section 217.388(c)
of an Appendix G unit or a unit included in an emissions averaging plan must
maintain records that demonstrate compliance with the requirements of this
Subpart Q which include, but are not limited to:
1)
Identification, type (e.g., lean-burn, gas-fired), and location of each unit.
2)
Calendar date of the record.
3)
The number of hours the unit operated on a monthly basis, and during
each ozone season.
4)
Type and quantity of the fuel used on a daily basis.
5)
The results of all monitoring performed on the unit and reported
deviations.
6)
The results of all tests performed on the unit.
7)
The plan for performing inspection and maintenance of the units, air
pollution control equipment, and the applicable monitoring device
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15
pursuant to Section 217.388(d)(c).
8)
A log of inspections and maintenance performed on the unit’s air
emissions, monitoring device, and air pollution control device. These
records must include, at a minimum, date, load levels and any manual
adjustments along with the reason for the adjustment (e.g., air to fuel ratio,
timing or other settings).
9)
If complying with the emissions averaging plan provisions of Sections
217.388(b) and 217.390 copies of the calculations used to demonstrate
compliance with the ozone season and annual control period limits,
noncompliance reports for the ozone season, and ozone and annual control
period compliance reports submitted to the Agency.
10)
Identification of time periods for which operating conditions and pollutant
data were not obtained by either the CEMS or alternate monitoring
procedures including the reasons for not obtaining sufficient data and a
description of corrective actions taken.
11)
Any NO
x
allowance reconciliation reports submitted pursuant to Section
217.392(c)(3).
b)
The owner or operator of an affected unit or unit included in an emissions
averaging plan must maintain the records required by subsectionssubsection (a) or
(d) of this Section, as applicable, for a period of five-years at the source at which
the unit is located. The records must be made available to the Agency and
USEPA upon request.
c)
Reporting Requirements
1)
The owner or operator must notify the Agency in writing 30 days and five
days prior to testing pursuant to Section 217.394(a) and (b) and:
A)
If after the 30-days notice for an initially scheduled test is sent,
there is a delay (e.g., due to operational problems) in conducting
the performance test as scheduled, the owner or operator of the
unit must notify the Agency as soon as possible of the delay in the
original test date, either by providing at least seven days prior
notice of the rescheduled date of the performance test, or by
arranging a new test date with the Agency by mutual agreement;
B)
Provide a testing protocol to the Agency 60 days prior to testing;
and
C)
Not later than 30 days after the completion of the test, submit the
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16
results of the test to the Agency.
2)
Pursuant to the requirements for monitoring in Section 217.394(d), the
owner or operator of the unit must report to the Agency any monitored
exceedances of the applicable NO
x
concentration from Section 217.388(a)
or (b) within 30 days after performing the monitoring.
3)
Within 90 days after permanently shutting down an affected unit or a unit
included in an emissions averaging plan, the owner or operator of the unit
must withdraw or amend the applicable permit to reflect that the unit is no
longer in service.
4)
If demonstrating compliance through an emissions averaging plan:
A)
By October 31 following the applicable ozone season, the owner or
operator must notify the Agency if he or she cannot demonstrate
compliance for that ozone season; and
B)
By January 3130 following the applicable calendar year, the owner
or operator must submit to the Agency a report that demonstrates
the following:
i)
For all units that are part of the emissions averaging plan,
the total mass of allowable NO
x
emissions for the ozone
season and for the annual control period;
ii)
The total mass of actual NO
x
emissions for the ozone
season and annual control period for each unit included in
the averaging plan;
iii)
The calculations that demonstrate that the total mass of
actual NO
x
emissions are less than the total mass of
allowable NO
x
emissions using equations in Sections
217.390(f) and (g); and
iv)
The information required to determine the total mass of
actual NO
x
emissions and the calculations performed in
subsection (cd)(4)(B)(iii) of this Section.
5)
If operating a CEMS, the owner or operator must submit an excess
emissions and monitoring systems performance report in accordance with
the requirements of 40 CFR 60.7(c) and 60.13, or 40 CFR 75 incorporated
by reference in Section 217.104, or an alternate procedure approved by the
Agency or USEPA and included in a federally enforceable permit.
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12/20/2007 4:17 PM
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17
6)
If using NO
x
allowances to comply with the requirements of Section
217.388, reconciliation reports as required by Section 217.392(c)(3).
d)
The owner or operator of an affected unit that is complying with the low usage
provisions of Section 217.388(c) must:
1)
For each unit complying with Section 217.388(c)(1), maintain a record of
the NO
x
emissions for each calendar year;
2)
For each unit complying with Section 217.388(c)(2), maintain a record of
bhp or MW hours operated each calendar year; and
3)
For each unit utilizing NO
x
allowances for compliance pursuant to Section
217.392(c)(3), maintain and submit any NO
x
allowance reconciliation
reports.
(Source: Amended at
Ill. Reg.
, effective
)
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18
Part 211:
Section 211.1920
Emergency or Standby Unit
“Emergency or Standby Unit” means, for a stationary gas turbine or a stationary reciprocating
internal combustion engine, a unit that:
a)
Supplies power for the source at which it is located but operates only when the
normal supply of power has been rendered unavailable by circumstances beyond
the control of the owner or operator of the source and only as necessary to assure
the availability of the engine or turbine. An emergency or standby unit may not
be operated to supplement a primary power source when the load capacity or
rating of the primary power source has been reached or exceeded.
b)
Operates exclusively for firefighting or flood control or both.
c)
Operates in response to and during the existence of any officially declared
disaster or state of emergency.
d)
Operates for the purpose of testing, repair or routine maintenance to verify its
readiness for emergency or standby use.
e)
Notwithstanding any other subsection in this Section, emergency or standby units
may operate an additional 50 hours per year in non-emergency situations.
The term does not include equipment used for purposes other than emergencies, as
described above, such as to supply power during high electric demand days.
(Source: Amended at
Ill. Reg.
, effective
)
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19
35 Ill. Adm. Code 201.146
Use the language as it appeared in the first notice as set forth in the Ill. Reg. dated May 4,
2007.
Electronic Filing - Received, Clerk's Office, December 20, 2007

AMENDED
TECHNICAL SUPPORT DOCUMENT
FOR CONTROLLING NO
x
EMISSIONS
FROM STATIONARY RECIPROCATING INTERNAL
COMBUSTION ENGINES AND TURBINES
R07-19
AQPSTR 07-05
December 20, 2007
ILLINOIS ENVIRONMENTAL PROTECTION AGENCY
AIR QUALITY PLANNING SECTION
DIVISION OF AIR POLLUTION CONTROL
BUREAU OF AIR
1021 NORTH GRAND AVENUE EAST
P.O. BOX 19276
SPRINGFIELD, IL 62794-9276
Electronic Filing - Received, Clerk's Office, December 20, 2007

Table of Contents
Page
List of Figures................................................................................................................. 3
List of Tables .................................................................................................................. 4
List of Acronyms............................................................................................................ 5
Executive Summary....................................................................................................... 7
1.0
Introduction........................................................................................................ 9
2.0
Background ........................................................................................................11
2.1
National Ambient Air Quality Standards (NAAQS) for Ozone and
Fine Particulates.......................................................................................11
2.2
Reasonably Available Control Technology (RACT)...............................13
2.3
Reasonable Further Progress (RFP).........................................................14
3.0
Process Description and Sources of Emissions................................................16
3.1
Stationary Reciprocating Internal Combustion Engines (RICE).............16
3.2
Stationary Turbines..................................................................................17
4.0
Technical Feasibility of Controls......................................................................19
4.1
Air/Fuel Ratio Adjustment.......................................................................19
4.2
Ignition Timing Retard ............................................................................20
4.3
Prestratified Charge .................................................................................21
4.4
Low Emission Combustion (LEC)...........................................................21
4.5
Water/Steam Injection .............................................................................22
4.6
Dry Low-NOx Combustors......................................................................23
4.7
Non-Selective Catalytic Reduction (NSCR)............................................24
4.8
Selective Catalytic Reduction (SCR).......................................................25
4.9
Technical Feasibility of Controls Summary ............................................25
5.0
Cost Effectiveness of Controls ..........................................................................27
5.1
Cost Effectiveness of Controls on RICE .................................................27
5.2
Cost Effectiveness of Controls on Turbines ............................................29
6.0
Existing and Proposed Regulations..................................................................31
6.1
Existing Illinois Regulations....................................................................31
6.2
Other States Regulations..........................................................................31
6.3
Proposed Illinois Regulations ..................................................................33
7.0
Potentially Affected Sources .............................................................................38
8.0
Emissions Reductions………………………………………………………….39
9.0
Summary.............................................................................................................40
10.0
References...........................................................................................................42
Attachment A
List of Impacted RICE and Turbines ..................................................44
Electronic Filing - Received, Clerk's Office, December 20, 2007

List of Figures
Figure 2-1
PM
2.5
Nonattainment Areas .....................................................................12
Figure 2-2
8-Hour Ozone Nonattainment Areas .......................................................12
Electronic Filing - Received, Clerk's Office, December 20, 2007

 
List of Tables
Table 3-1
Uncontrolled NO
x
Emissions from RICE and Turbines ................................18
Table 4-1
Potential Emissions Reductions from RICE ..................................................26
Table 4-2
Potential Emissions Reductions from Turbines.............................................26
Table 5-1
Cost Effectiveness for Retrofit of Various NO
x
Control Systems.................28
Table 5-2
Costs and Cost Effectiveness of LEC Controls in 2004 Dollars ...................29
Table 5-3
Cost Effectiveness for Various NO
x
Control Systems for Turbines..............30
Table 6-1
NO
x
Control Requirements for RICE in Other States ...................................32
Table 6-2
NO
x
Control Requirements for Turbines in Other States ..............................33
Table 6-3
Example of Averaging Plan-Case 1...............................................................36
Table 6-4
Example of Averaging Plan-Case 2...............................................................36
Table 7-1
Number of Affected Sources .........................................................................38
Table 8-1
Estimated NO
x
Emissions Reductions from Affected RICE .........................39
Electronic Filing - Received, Clerk's Office, December 20, 2007

List of Acronyms
A/F
air-to-fuel
ACT
Alternative Control Techniques
document
ALAPCO
Association of Local Air Pollution Control Officials
BART
Best Available Retrofit Technology
bhp
brake horsepower
Board
Illinois Pollution Control Board
BOOS
burner out of service
Btu
British Thermal Unit
CAA
Clean Air Act
CAIR
Clean Air Interstate Rule
CO
carbon monoxide
CO
2
carbon dioxide
CPI
Consumer Price Index
CT
combustion tuning
EE
energy efficiency
EGU
electric generating unit
FIP
Federal Implementation Plan
HC
hydrocarbons
Illinois EPA
Illinois Environmental Protection Agency
ITR
ignition timing retard
Lb
pound
LADCO
Lake Michigan Air Directors’ Consortium
LEC
low emission combustion
mmBtu
million British Thermal Units
MW
megawatt
NAA
nonattainment area
NAAQS
National Ambient Air Quality Standards
NO
x
nitrogen oxide
O
2
oxygen
O
3
ozone
PM
2.5
fine particulate matter
ppm
parts per million
ppmv
parts per million by volume
PSC
prestratified charge
PTE
potential to emit
RACT
Reasonably Available Control Technology
RFP
Reasonable Further Progress
RIA
Regulatory Impact Analysis
RICE
stationary reciprocating internal combustion engine
SCR
selective catalytic reduction
SI
spark-ignited
SIP
State Implementation Plan
SNCR
selective non-catalytic reduction
SO
2
sulfur dioxide
STAPPA
State and Territorial Air Pollution Program
Electronic Filing - Received, Clerk's Office, December 20, 2007

TSD
Technical Support Document
TPY
tons per year
VOM
volatile organic material
ug/m
3
microgram per cubic meter
U.S. EPA
United States Environmental Protection Agency
Electronic Filing - Received, Clerk's Office, December 20, 2007

Executive Summary
This technical support document (TSD) presents the rationale, documentation, and methodology
developed by the Illinois Environmental Protection Agency (Illinois EPA) in support of its
proposal to amend regulations controlling nitrogen oxide (NO
x
) emissions from stationary
reciprocating internal combustion engines (RICE) and and propose regulations controlling NO
x
emissions from turbines. Reciprocating internal combustion engines and turbines are a
significant source category of NO
x
emissions in Illinois and a contributor to fine particulate
matter (PM
2.5
) and ozone levels in areas of Illinois that are designated as nonattainment areas
(NAAs) for these pollutants. This proposal is intended to address the requirement for NO
x
Reasonably Available Control Technology (RACT) for these source categories in Illinois’ 8-
hour ozone and PM
2.5
nonattainment areas (NAAs). The Illinois EPA intends to address RACT
requirements for other source categories in a separate rulemaking. This proposal will also
address, in part, federal requirements to achieve emission reductions needed to ensure
Reasonable Further Progress (RFP) toward attainment of the NAAQS.
The Illinois EPA is proposing to control NO
x
emissions from sources located in the NAAs that
have a potential to emit (PTE) of 100 tons per year (TPY) of NO
x
, aggregated from all the
affected units at the sources. Regulations to control NO
x
emissions from RICE down to 500
brake-horsepower (bhp) and turbines down to 3.5 megawatts (MW) are included in this proposal.
The proposed regulation does not apply to emergency standby engines; engines used in research
and testing for the purposes of performance verification of engines; engines/turbines used for
agricultural purpose; and certain portable engines. The Illinois EPA, in consultation with the
affected sources, is proposing a low-usage limit of 8 million bhp-hour/year, aggregated from all
affected engines at a source, and 20,000 MW-hour/year, aggregated from all affected turbines at
a source.
The NO
x
control levels proposed in this submittal are considered reasonable, attainable, and
cost-effective. The NO
x
emissions levels are prescribed in parts per million by volume (ppmv)
corrected to 15 percent oxygen (O
2
) on a dry basis. The NO
x
limits for engines are 150 ppmv for
spark-ignited rich-burn; 210 ppmv for spark-ignited lean-burn; 365 ppmv for Worthington
Electronic Filing - Received, Clerk's Office, December 20, 2007

engines; and 660 ppmv for diesel engines. For turbines, the NO
x
limits are 42 ppmv for gas-
fired, and 96 ppmv for liquid-fired turbines. An owner or operator may comply with the control
requirements by averaging the emissions of affected units. Compliance with the emission limits
will be determined on both an ozone season (May 1 to September 30) and an annual (January 1
to December 31) basis each year.
The Illinois EPA relied on the cost data and cost effectiveness estimates contained in the U.S.
EPA’s alternative control technology (ACT) guidance documents prepared by the U.S EPA for
RICE and turbines. The proposed regulation amends 35 Ill. Adm. Code Subpart Q and will
potentially affect a total of 63 RICE and 58 turbines in Illinois not previously affected by
Subpart Q. When fully implemented, NO
x
emissions will be reduced statewide by
approximately 2,155 TPY and 1,020 tons per ozone control season.
Electronic Filing - Received, Clerk's Office, December 20, 2007

1.0
Introduction
This TSD presents the rationale, documentation, and methodology developed by the Illinois EPA
to support its proposed regulation to control NO
x
emissions from RICE and turbines. RICE and
turbines are significant sources of NO
x
emissions in Illinois. Based on the Illinois EPA’s 2002
base year emissions inventory, out of 277,899 TPY of NO
x
emissions from point sources in
Illinois, approximately 23,347 TPY of NO
x
were emitted from RICE and turbines. This
represents approximately 8.4 percent of Illinois’ total point source NO
x
emissions.
The Illinois EPA has the responsibility under the CAA to develop a State Implementation Plan
(SIP) which provides for Reasonably Available Control Technology (RACT) for NO
x
in
moderate 8-hour ozone and PM
2.5
NAAs. This proposal is intended to address the requirement
for RACT for NO
x
for these source categories. The Illinois EPA intends to address RACT
requirements for other source categories in a separate rulemaking. This proposal will also
address, in part, federal requirements to achieve emission reductions needed to meet the RFP
requirements for the 8-hour ozone standard.
A brief summary of the various sections in this TSD is as follows:
Section 2 provides background information on ozone and particulate matter air quality and the
effects of these pollutants on human health. The regulatory requirements that are being
addressed by this proposal are also described in Section 2.
Section 3 contains descriptions of the various types of internal combustion engines and turbines
and how NO
x
emissions are generated by these processes. Also presented in this Section are the
estimated uncontrolled levels of NO
x
emissions from RICE and turbines in Illinois.
Section 4 identifies control techniques available to reduce NO
x
emissions from RICE and
turbines.
Electronic Filing - Received, Clerk's Office, December 20, 2007

General cost information on various control technologies is discussed in Section 5. This Section
provides cost information for the various control technologies that are available to control NO
x
emissions from stationary RICE and turbines, described in terms of cost effectiveness of controls
(i.e., dollars per ton of NO
x
emission reduced) to comply with the proposed regulation.
Existing and proposed regulations are discussed in Section 6. This Section summarizes the
existing Illinois NO
x
regulations, and other states’ NO
x
regulations for RICE and turbines, and
concludes with an explanation of the proposed regulations.
Sources in Illinois that are potentially affected by the proposed regulations are listed in
Section 7. Also described in this Section is the methodology that the Illinois EPA used to
identify sources that may potentially be affected by the proposed regulations.
Section 8 provides an estimate of emissions reductions that will be achieved by implementing
the Illinois EPA’s proposal and explains the methodology used by the Illinois EPA to estimate
NO
x
emissions reductions from this proposal.
Finally, a summary of this TSD is provided in Section 9.
Electronic Filing - Received, Clerk's Office, December 20, 2007

2.0
Background
2.1
National Ambient Air Quality Standards for Ozone and Fine Particulates
The U.S. EPA revised the NAAQS for particulate matter and ozone in 1997.
1, 2
The revised
standards for particulate matter recognized that the smallest particles, those less than equal to 2.5
microns in diameter, have adverse health effects in the humans. In response to the establishment
of the NAAQS for PM
2.5
, U.S. EPA designated two areas in Illinois as NAAs: the Chicago area
(consisting of Cook, DuPage, Kane, Lake, McHenry, and Will counties, and the townships of
Oswego, in Kendall County, and Aux Sable and Goose Lake, in Grundy County), and the Metro-
East St. Louis area (consisting of Madison, Monroe, and St. Clair counties, and Baldwin
Township in Randolph County). Figure 2-1 shows the PM
2.5
NAAs for Illinois and nearby
states. These designations became effective on April 5, 2005 (70
FR
943).
3
The revised NAAQS for ozone replaced the previous 1-hour averaging time with an 8-hour
averaging time, and reduced the applicable ambient concentration threshold from 0.12 parts per
million (ppm) to 0.08 ppm. U.S. EPA designated certain areas in Illinois and other states as
nonattainment for this air quality standard. Figure 2-2 shows the 8-hour ozone NAAs for the
states in the central United States. These designations became effective on June 15, 2004 (69
FR
23858).
4
Geographically, the ozone NAAs in Illinois are roughly the same areas that were
designated as nonattainment for PM
2.5.
The exception is in the Metro-East area. The 8-hour
ozone NAA includes Jersey County and does not include Baldwin Township in Randolph
County, while the PM
2.5
NAA does not include Jersey County but does include Baldwin
Township.
Fine particles and ozone are associated with thousands of premature deaths and illnesses each
year in the United States. In revising the NAAQS for particulate matter, U.S. EPA found that
fine particles aggravate respiratory, lung, and cardiovascular diseases, decrease lung function,
and increase asthma attacks, heart attacks, and cardiac arrhythmia. As a consequence of
exposure to PM
2.5
, hospital admissions and emergency room visits increase as does absenteeism
from school and work. Older adults, people with heart and lung disease, and children are the
segments of society that are particularly sensitive to fine particle exposure. Attainment of the
Electronic Filing - Received, Clerk's Office, December 20, 2007

 
PM
2.5
standard will prolong thousands of lives in Illinois and other states. Additional
information on the health effects of fine particles can be found on U.S. EPA’s website at
http://www.epa.gov/ttn/naaqs/standards/pm/s_pm_index.html.
Figure 2-1
Figure 2-2
PM
2.5
Nonattainment Areas
8-Hour Ozone Nonattainment Areas
U.S. EPA’s revised NAAQS for ozone was intended to provide increased protection to the
public, especially children and other at-risk populations, against a wide range of ozone-induced
health effects. In setting the 8-hour ozone standard, U.S. EPA found that exposures to ozone of
one to three hours in length had been found to irritate the respiratory system, causing coughing,
throat irritation, and chest pain. Ozone exposure can limit lung function and breathing capacity,
resulting in rapid and shallow breathing, thereby lowering or curtailing a person’s normal
activity level. As with PM
2.5
exposure, ozone exposure increases asthma attacks for people with
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13
respiratory disorders. Longer-term ozone exposure may result in damage to the lung tissue and
lining from inflammation, which can produce permanent and irreversible changes in lung
function. Children and adults who are active outdoors are particularly susceptible to ozone, as
are people with asthma and respiratory diseases. Ozone also affects sensitive ecosystems and
vegetation, resulting in reduced crop yields, reduced growth and lowered pest resistance, and a
lowered ability for plants and trees to survive. Additional information on the health effects to
humans and vegetation from exposure to ozone is found on U.S. EPA’s website:
http://www.epa.gov/ttn/naaqs/standards/ozone/s_o3 _index.html
U.S. EPA has long recognized the relationship between emissions of NO
x
and adverse regional
air quality issues and federal efforts to reduce emissions of NO
x
were initiated in 1990. The
CAA placed several new requirements to reduce NO
x
emissions. The federal programs that
affect NO
x
emissions sources are discussed in the following subsections.
2.2 Reasonably Available Control Technology (RACT)
Pursuant to Sections 172, 182(b) and (f) of the CAA, RACT is required for all existing major
sources of the applicable criteria pollutant and its precursors located in NAAs. This rulemaking
addresses NO
x
as a precursor to ozone and PM
2.5
. U.S. EPA defines RACT as the lowest
emission limitation that a particular source is capable of meeting by the application of control
technology that is reasonably available considering technological feasibility and economic
reasonableness (70
Fed. Reg.
71612).
5
The major source threshold for moderate NAAs is
defined as 100 TPY. A source generally consists of several units that emit pollutants. The sum
of emissions from all units at the source determines if a unit is major and thus subject to RACT
requirements. This rulemaking addresses two RACT categories, engines and turbines.
Additional RACT categories will be addressed in subsequent rulemakings.
RACT is not a new requirement under the CAA, but one that had previously been waived with
respect to Illinois’ two ozone NAAs. For the implementation of the 1-hour ozone NAAQS,
Illinois requested and received a waiver under Section 182(f) of the CAA from the requirement
to implement NO
x
RACT for major sources located in ozone NAAs. With respect to the 8-hour
ozone NAAQS, the Illinois EPA will not pursue the NO
x
waiver because the local-scale, NO
x
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14
disbenefit (i.e., the scavenging of ambient ozone by local nitrogen oxide emissions) is not as
important for the longer 8-hour averaging time. Also, the level of the 8-hour ozone standard is
closer to regional background levels in the Midwest, which argues for the application of controls
on a regional basis. The Illinois EPA therefore intends to submit a SIP revision to implement
NO
x
RACT requirements per Sections 182(b)(2) and 182(f) of the CAA. Pursuant to 40 CFR
51.912, the State is required to submit a RACT SIP no later than 27 months (September 2006)
after designation of NAAs that provides for implementation of the measures no later than the
first ozone season that occurs 30 months after the RACT SIP is due (2009 ozone season). (70
FR
71611, 71701)
5
U.S. EPA finalized its implementation guidance for the PM
2.5
NAAQS on April 25, 2007.
6
This
guidance document addresses RACT requirements for PM
2.5
and its precursors, including NO
x
.
Based on U.S. EPA’s implementation guidance, Illinois’ SIP must include a demonstration that
all Reasonably Available Control Measures (RACM), which includes RACT, have been adopted
as necessary to demonstrate attainment as expeditiously as practicable and to meet any RFP
requirements. In determining RACM, the state must adopt technically and economically feasible
measures if collectively the measures would advance the attainment date by one year. Therefore,
for PM
2.5
, RACT is part of RACM, unlike ozone, and is not an independent requirement. In the
case of electric generating units (EGUs) regulated under the Clean Air Interstate Rule (CAIR),
however, U.S. EPA’s guidance does require that EGUs with existing controls must operate those
controls year-round to satisfy RACT.
Since affected emission units, engines and turbines, under this proposal must comply with
seasonal emission limitations to satisfy RACT for ozone, it is appropriate to also require that
these limitations continue on an annual basis to improve PM
2.5
air quality. Continuing controls
on an annual basis will not, in most cases, cause significant additional costs to affected sources,
and is consistent with the regulations previously adopted for engines under Subpart Q.
2.3
Reasonable Further Progress (RFP)
For an area classified as an ozone NAA under Subpart 2 of Part D of the CAA, and the
requirements of Section 182, a state is required to submit a SIP revision that includes measures
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15
that ensure RFP towards the emissions reductions targets needed for attainment (40 CFR
51.910). To meet RFP requirements of Section 172(c)(2) of CAA, the state is required to submit
no later than 3 years (June 2007) following designation for the 8-hour NAAQS, a SIP providing
for RFP from the baseline year (2002) within 6 years after the baseline year (2008). The state
may use either NO
x
for VOM emission reductions (or both) to achieve the RFP reduction
requirement. Use of NO
x
emissions reductions must meet the criteria in Section 182(c)(2)(C) of
the CAA. For each subsequent 3-year period out to the attainment date, the RFP SIP must
provide for an additional increment of progress.
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16
3.0
Process Description and Sources of Emissions
3.1
Stationary Reciprocating Internal Combustion Engines (RICE)
“Controlling Nitrogen Oxides Under the Clean Air Act: A Menu of Options,”
7
a document
published in July 1994 by the State and Territorial Air Pollution Program Administrators
(STAPPA)/Association of Local Air Pollution Control Official (ALAPCO), summarizes how
RICE operate and how they generate NO
x
emissions. RICE are the stationary relatives of motor
vehicle engines, using the combustion of fuel in cylinders to drive pistons with crankshafts,
which convert the linear piston motion to rotary motion. Ignition of the fuel in reciprocating
engines may be initiated by a spark or by the heat generated in the compression stroke of a
piston. Spark ignited (“SI”) engines typically burn gasoline or, in large engines, natural gas,
while compression ignition engines burn diesel oil or a dual-fuel (diesel oil-natural gas) mixture.
Reciprocating engines have either four-stroke or two-stroke operating cycles. A typical
automotive engine uses a four-stroke cycle of intake, compression, power, and exhaust. Two-
stroke engines complete the power cycle in a single engine revolution compared to two
revolutions for four-stroke engines.
A final classification of reciprocating engines that influence the choice of NOx control
alternatives is based on the engine air-to-fuel ratio and the exhaust oxygen content. Rich-burn
engines, which include four-stroke spark ignition engines, typically operate with an air-to-fuel
ratio near stoichiometric and exhaust oxygen concentrations of one percent or less. Lean-burn
engines, which include two-stroke spark ignition and all compression ignition engines, have a
lean air-to-fuel ratio and typical exhaust oxygen concentrations of greater than one percent.
Reciprocating engines are used throughout the United States to drive compressors, pumps,
electric generators and other equipment. One prominent use of large engines is to drive natural
gas pipeline compressor stations. Except for three engines compressing ammonia at a chemical
plant, all engines affected by the NO
x
SIP Call-Phase 2 rule in Illinois are used to compress
natural gas at natural gas pipeline stations. All currently operating RICE that are large enough to
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17
be affected by the Illinois EPA proposal are either rich-burn or lean-burn engines that burn
natural gas exclusively.
RICE are significant sources of NO
x
because they burn large amounts of fuel at high
temperatures and pressures, which cause the nitrogen and oxygen in the air that sustains the
combustion to unite and form the various oxides of nitrogen that constitute NO
x
. Thermal NO
x
is the predominant mechanism by which NO
x
is formed in RICE. Reducing combustion
temperatures and pressures are therefore effective in reducing NOx emissions from reciprocating
engines. Although in theory additional NO
x
could be formed from nitrogen found in the fuel,
virtually all RICE burn fuels containing little if any nitrogen. Therefore, fuel NO
x
formation is
minimal in RICE.
3.2
Stationary Turbines
The same STAPPA/ALAPCO document,
7
referenced to previously in Section 3.1 also provides a
description and sources of NO
x
emissions from turbines. A gas turbine is an internal combustion
engine that operates with rotary rather than reciprocating motion. There are three basic phases in
the operation of a turbine: compression, combustion, and conversion to power. Ambient air is
drawn in and compressed up to 30 times ambient pressure and directed to the combustor section
where fuel is introduced, ignited, and burned. Hot combustion gases are then diluted with
additional air from the compressor and directed to the turbine section at temperatures up to
2,350°F. Energy from the hot expanding exhaust gases are then recovered in the form of a shaft
horsepower, of which 50 percent is needed to drive the internal compressor, and the balance of
recovered shaft energy is available to drive external load units.
The heat content of gases exiting the turbine can either be discarded without heat recovery
(simple cycle); used with a heat exchanger to preheat combustion air entering the combustor
(regenerative cycle); used with or without supplementary firing, in a heat recovery steam
generator to raise process steam temperature (cogeneration); or used with or without
supplementary firing to raise steam temperature for a steam turbine Rankine cycle (combined
cycle or repowering). The majority of turbines used in large stationary installations are either
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18
peaking simple cycle, two-shaft or base load, combined cycle turbines. Smaller turbines are
used to compress gas in natural gas pipelines or to generate electricity.
The principle type of NO
x
formed in a turbine firing natural gas or distillate oil is thermal NOx.
Most thermal NO
x
is formed in high temperature stoichiometric flame pockets downstream of
fuel injectors where combustion air has mixed sufficiently with the fuel to produce the peak
temperature fuel/air interface. The maximum thermal NO
x
production occurs at a slightly lean-
fuel mixture because of excess oxygen available for reaction. The control of stoichiometry is
critical in achieving reduction in thermal NO
x
. The thermal NO
x
generation also decreases
rapidly as the temperature drops below the adiabatic temperature (for a given stoichiometry).
Maximum reduction in thermal NO
x
generation can thus be achieved by control of both the
combustion temperature and the stoichiometry.
Table 3-1 describes the uncontrolled NO
x
emissions in parts per million by volume (ppmv)
corrected to 15 percent oxygen (O
2
) from various types of RICE and turbines.
Table 3-1
Uncontrolled NO
x
Emissions from RICE and Turbines
7,8
Type of Unit
Uncontrolled NO
x
Emissions (ppm@ 15% O
2
)
Range
Average
Rich-Burn SI Engines
880 – 1090
1060
Lean-Burn SI Engines
580 – 1360
1230
Diesel Engines
820 – 950
880
Dual-Fuel Engines
360 – 780
620
Natural Gas-fired Combustion Turbine
99 – 430
264
Distillate Oil fired Combustion
Turbine
150 – 680
415
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19
4.0
Technical Feasibility of Controls
For reciprocating engines and turbines both combustion controls and post-combustion catalytic
reduction technologies can be applied to reduce NO
x
emissions. Combustion controls for
reciprocating engines, include air/fuel ratio adjustments, low emission combustion, and
prestratified charge. These controls function by modifying the combustion zone air/fuel ratio,
thus influencing oxygen availability and peak flame temperature. Ignition timing retard lowers
the peak flame temperature by delaying the onset of combustion. For turbines water/steam
injection and dry low-NO
x
combustors are the combustion control technologies used to reduce
NO
x
emissions. The two post-combustion control strategies that destroy NO
x
for RICE and
turbines are selective catalytic reduction and non-selective catalytic reduction. U.S. EPA’s
Alternative Control Techniques Document--NO
x
Emissions from Stationary Reciprocating
Internal Combustion Engines
8
, and NO
x
Emissions from Stationary Gas Turbines,
9
provide
additional details on these NO
x
control techniques.
4.1
Air/Fuel Ratio Adjustment
Lowering the air-to-fuel (A/F) ratio in rich-burn engines limits oxygen availability in the
cylinder, thus decreasing NO
x
emissions both by lowering peak flame temperature and by
producing a reducing atmosphere. It is generally applicable to rich-burn engines and, in addition
to simple adjustment of the A/F ratio, requires the installation of a feedback controller so that
changes in load and other operating conditions may be followed. Additional modification of
turbocharged engines may be necessary.
Air/fuel ratio adjustment is a well-demonstrated alternative in rich-burn engines and typically
yields 10-40 percent reductions in NO
x
emissions. This range is broad in part because a wide
range of existing air/fuel ratios translates into variable scope for emissions reductions using this
technique.
In lean-burn engines, increasing the A/F ratio decreases NO
x
emissions. Extra air dilutes the
combustion gases, thus lowering peak flame temperature and reducing thermal NO
x
formation.
In order to avoid an engine’s capacity being derated, air flow to the engine must be increased at
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20
constant fuel flow, with the result that installation of a turbocharger (or modification of an
existing one) is necessary to implement this technique. An automatic A/F controller also will be
required for variable load operation.
Air/fuel ratio adjustment is generally applicable to lean-burn engines, although space constraints
may limit the extent to which turbocharger capacity may be increased. This control method is
most effective on fuel injected engines, in that carbureted engines do not have the same A/F in
each cylinder, thereby limiting changes in this ratio.
Reductions in lean-burn engine NO
x
emissions of 5-30 percent are possible by modifying the
A/F ratio. Achievable emissions reductions are limited by combustion instability and lean
misfire that occur as the lean flammability limit is approached, and by decreased engine
efficiency.
Air/fuel ratio adjustment is not applicable to compression ignition engines.
4.2 Ignition Timing Retard
Ignition timing retard (ITR) lowers NO
x
emissions by moving the ignition event to later in the
power stroke when the piston has begun to move downward. Because the combustion chamber
volume is not at its minimum, the peak flame temperature will be reduced, thus reducing thermal
NO
x
formation.
ITR is applicable to all engines. It is implemented in spark ignition engines by changing the
timing of the spark, and in compression ignition engines by changing the timing of the fuel
injection. While timing adjustments are straightforward, replacement of the ignition system with
an electronic ignition control or injecting timing system will provide better performance with
varying engine load and conditions.
Emissions reductions attainable using ITR are variable, depending upon the engine design and
operating conditions, and particularly on the air/fuel ratio. Reductions also are restricted by
limitations on the extent to which ignition may be delayed, in that excess retard results in engine
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21
misfire. Retard also normally results in decreased fuel efficiency. For spark ignition engines,
achievable emissions reductions vary from 0-40 percent, and for compression ignition engines,
from 20-30 percent.
ITR results in increased exhaust temperatures, which may result in reduced exhaust valve and
turbocharger life. On diesel engines, it also may result in black smoke.
4.3
Prestratified Charge
Prestratified charge (PSC) is a technology for injecting fuel and air into the intake manifold in
distinct “slugs,” which become separate fuel and air layers upon intake into the cylinders. This
control alternative thus creates a fuel-rich, easily ignitable mixture around the spark plug and an
overall fuel-lean mixture in the piston. Combustion occurs at a lower temperature, thereby
producing much less thermal NO
x
, but without misfire even as the low flammability limit is
approached.
PSC is applicable to carbureted, spark ignition four-stroke engines. Engines, which are fuel-
injected or blower-scavenged, cannot use this technique. Kits for retrofitting prestratified charge
are available for most engines and require installation of new intake manifolds, air hoses and
filters, control valves, and a control system. Controlled emissions normally are less than 2
g/bhp-hr (140 ppm) on natural-gas-fueled engines, corresponding to emissions reductions of 80-
95 percent.
4.4 Low Emission Combustion
Low emission combustion (LEC) is the combustion of a very fuel-lean mixture. Under these
conditions, NO
x
emissions, as well as carbon monoxide (CO) and hydrocarbons (HC), are
severely reduced.
Implementation of LEC requires considerable engine modification. Rich-burn engines must be
entirely rebuilt, with addition or replacement of the turbocharger and installation of new air
intake and filtration, carburetor and exhaust systems. The difficulty of burning very lean
mixtures results in the need to modify the combustion chamber, which implies replacing pistons,
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22
cylinder heads, the ignition system and the intake manifold. While small cylinder designs that
promote air-fuel mixing are available, precombustion chambers must be installed on larger
engines. The chambers have 5-10 percent of the cylinder volume and allow ignition of a fuel-
rich mixture that ignites the lean mixture in the cylinder.
The applicability of LEC is somewhat limited. Conversion kits are not available for all engines
and refitted engines may have degraded load-following capabilities. Achievable controlled
emissions are 1-2 g/bhp-hr (70-140 ppm) for rich-burn engines, which corresponds to an
emissions reduction of 70-90 percent, and 1.5-3 g/bhp-hr (105-210 ppm) for lean-burn spark
ignition engines, or an emissions reduction of about 80-93 percent.
LEC is not effective for diesel engines, but does work for dual-fuel engines, allowing a reduction
in the fraction of diesel oil pilot fuel to 1 percent of the total, and limiting emissions to 1-2
g/bhp-hr (70-140 ppm), a decrease in emissions of 60-80 percent. Some reductions in exhaust
opacity have been claimed when LEC is implemented on dual-fuel engines.
4.5
Water/Steam Injection
Water/steam injection lowers peak flame temperatures by providing an inert diluent, thus
limiting thermal NO
x
formation. Water may be injected directly into the turbine combustor, or
may be converted to steam using turbine exhaust waste heat (with a heat recovery steam
generator), and then injected into the combustor.
More steam than water must be used to achieve a comparable NO
x
reduction. However, the use
of steam results in a lower energy penalty than the use of water and may even provide NO
x
reductions with no energy penalty if the waste heat used to generate steam would otherwise not
be recovered.
Wet injection is applicable to most, if not all, turbines, and has been applied to a large number of
turbines in the United States. Required equipment, in addition to water/steam injection nozzles,
includes a water treatment system, pumps or a steam generator, metering valves, and controls
and piping. Untreated water will lead to deposits on turbine blades, lowering efficiency and
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23
perhaps damaging the turbine. Most turbine manufacturers sell water and steam injection
systems.
Controlled NO
x
emissions are a function of the amount of water injected and of the fuel/nitrogen
content as wet injection limits only thermal NO
x
formation. For natural gas, controlled
emissions levels of 25-75 ppm are attained with water-to-fuel ratios of about 0.5 – 1.5 lb steam
/lb fuel. (Approximately 1-2 lb steam/lb fuel is needed for equivalent control, given the lower
heat capacity of steam relative to that of water.) For distillate oil, controlled emissions of 42-
110 ppm are attained with similar water-to-fuel ratios. These controlled emissions levels
correspond to 60-90 percent emissions reductions.
The need to increase water-to-fuel ratios for increased emission reductions limits NO
x
control
capabilities. High water-to-fuel ratios result in increased hydrocarbon and greatly increased CO
emissions. Further, because heating injected water consumes energy, turbine fuel efficiency may
decrease. Wet injection may increase required turbine maintenance as a result of pressure
oscillations or erosion caused by contaminates in the feed water.
Finally, the water treatment plant creates wastewater. This wastewater is enriched
approximately three-fold by the dissolved minerals and pollutants that were in the raw water.
4.6 Dry Low-NOx Combustors
Dry low-NO
x
combustors encompass several different technologies. Lean premixed combustion
is the commercially available technology that affords the largest NO
x
reductions. It functions by
providing a large amount of excess air to the combustion chamber, lowering peak temperatures
by dilution. Air and fuel are premixed in lean premixed combustors to avoid the creation of
local fuel-rich, and therefore high-temperature, regions.
While retrofit low-NO
x
combustors are not available for all turbine models, they have been
installed on many turbines in the United States. Lean premixed combustor retrofits face varying
difficulties. Because lean premixed combustors reduce thermal NO
x
generation only, they are
less effective on oil-fired than on gas-fired turbines. Except in the case of silo combustors,
Electronic Filing - Received, Clerk's Office, December 20, 2007

24
which are external to the turbine body, the retrofits may require some modification of the
combustor section of the turbine. Water/steam injection provides comparable reductions on oil-
fired turbines without retrofit of low-NO
x
combustors.
Controlled emissions levels achievable on gas-fired turbines are on the order of 25-42 ppm. On
some larger turbines, manufacturers are guaranteeing emissions of 9 ppm, and more will
approach this limit with improvements in technology. These figures correspond to NO
x
emissions reductions of 60-95 percent. Maximum reductions are attained only at high turbine
loads. Given reduced fuel requirements at low loads, premixing would yield air/fuel mixtures
near the lean flammability limit, with resulting flame instability and high CO emissions. Thus,
lean premixed combustors use diffusion flames at low loads.
4.7 Non-Selective Catalytic Reduction (NSCR)
Non-selective catalytic reduction (NSCR) uses the three-way catalysts found in automotive
applications to promote the reduction of NO
x
to nitrogen and water. Exhaust CO and HC are
simultaneously oxidized to carbon dioxide and water in this process.
NSCR is applicable only to rich-burn engines with exhaust oxygen concentrations below about 1
percent. Lean-burn engine exhaust will contain insufficient CO and HC for the reduction of the
NO
x
present. NSCR retrofits, in addition to the catalyst and catalyst housing, require installation
of an oxygen sensor and feedback controller to maintain an appropriate A/F ratio under variable
load conditions. Controlled emissions achievable with NSCR are below 1 g/bhp-hr (70 ppm),
corresponding to emissions reductions greater than 90 percent. NSCR controls are not feasible
for turbines.
7
4.8
Selective Catalytic Reduction
The catalyzed reduction of NO
x
with injected ammonia, referred to as selective catalytic
reduction (SCR), has been implemented on a number of gas, diesel, and dual-fuel engines in the
United States. and abroad. SCR is applicable only to lean-burn engines with greater than about
one percent exhaust oxygen, as oxygen is a reagent in the selective reduction reaction.
Electronic Filing - Received, Clerk's Office, December 20, 2007

25
Retrofitting SCR involves installation of the reactor and catalyst, appropriate ductwork, an
ammonia storage and distribution system, and a control system for variable load operation.
Achievable emissions reductions are limited only by the amount of catalyst used, and typically
are on the order of 90 percent, yielding controlled emissions below two g/bhp-hr (140 ppm).
Achievable NO
x
emissions reductions using SCR exceed 90 percent, which corresponds to
controlled emissions below 10 ppm and 25 ppm for many gas-fired and oil-fired turbines.
4.9
Technical Feasibility of Controls Summary
In summary, there are a number of techniques and control options available for reducing
emissions of NO
x
from RICE and turbines. The degree to which these various methods reduce
NO
x
emissions depends upon the type of engine and the fuel used in the engine. In their
publication “Controlling Nitrogen Oxides Under the Clean Air Act,”
7
STAPPA/ALAPCO
summarizes the potential emissions reductions from RICE and turbines. Tables 4-1 and 4-2
describe the NO
x
emissions reductions potential of the various control strategies for
reciprocating engines and turbines.
Electronic Filing - Received, Clerk's Office, December 20, 2007

 
26
Table 4-1
Potential Emissions Reductions from Reciprocating I. C. Engines
7
NO
x
Reduction Potential (%)
Control
Rich-Burn
Gas SI
Lean-Burn
Gas SI
Diesel
Dual Fuel
Air/Fuel Ratio Adjustment
10 – 40
5 - 30
N/A
N/A
Ignition Timing Retard
0 – 40
0 - 20
20 - 30
20 – 30
Prestratified Charge
80 – 90
N/A
N/A
N/A
Low Emission Combustion
70 – 90
80 - 93
N/A
60 – 80
Non-selective Catalytic Reduction
90 – 98
N/A
N/A
N/A
Selective Catalytic Reduction
N/A
90
80 - 90
80 – 90
Table 4-2
Potential Emissions Reductions from Turbines
7
Control
Emissions Reduction Potential (%)
Water/Steam Injection
70 - 90
Low-NOx Combustors
60 – 90
Selective Catalytic Reduction
90
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27
5.0
Cost Effectiveness of Controls
The U.S. EPA has prepared a number of estimates of the cost effectiveness of controlling NO
x
emissions from RICE. The most recent and significant estimates are contained in federal ACT
documents for RICE and turbines.
8 , 9
The Illinois EPA relied on these documents to estimate the
cost effectiveness of controlling Illinois NO
x
sources potentially affected by this proposed
rulemaking.
5.1 Cost Effectiveness of Controls on RICE
The Illinois EPA relied on U.S. EPA’s cost estimates from the ACT document for RICE.
8
To
estimate cost effectiveness of controls, U.S. EPA considers total capital costs and total annual
costs. The total capital cost is the sum of the purchased equipment costs, direct installation
costs, indirect installation costs, and contingency costs. Annual costs consist of the direct
operating costs of materials and labor for maintenance, operation, utilities, material replacement
and disposal, and indirect operating charges including plant overhead, general administration,
and capital recovery charges. Cost effectiveness, in dollars/ton of NO
x
removed, is calculated
for each control technique by dividing the total annual cost by the annual tons of NO
x
removed.
U.S. EPA’s ACT document describes the costs of various NO
x
controls applicable to RICE.
Depending on the type, size, and operating hours of the engine, the cost effectiveness of each
control varies from a few hundred to several thousands dollars per ton of NO
x
removed. The
cost information in the ACT document is reported in 1993 dollars. The Illinois EPA used
Consumer Price Index (CPI) conversion factor of 0.765 for 1993 to arrive at 2004 dollars. Table
5-1 summarizes the cost effectiveness of various control options for engines equal to or greater
than 500 bhp.
Based on the ACT, there are a number of control options available which achieve the control
levels proposed in this rulemaking. The cost effectiveness ranges from $163 to $5,961 per ton of
NO
x
removed on an annual basis.
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28
Table 5-1
Cost Effectiveness for Retrofit of Various NO
x
Controls Systems
8
Type of Control
Engine Size
(bhp)
Total Capital
Cost
(Thousands of 2004
dollars)
Cost
Effectiveness
(2004 dollars/ ton of
NO
x
removed)
Automatic A/F Control to Rich-Burn SI Engine
500 – 8000
14.9-32.0
567-1,080
Electronic Ignition to Rich-Burn SI Engine
500 – 8000
15.9-32.0
469-987
A/F + Electronic Ignition to Rich-Burn SI Engine
500 – 8000
30.8-63.9
540-1,065
Prestratified Charge to Rich-Burn SI Engine
500 – 8000
66.0-113.5
163-1,712
Prestratified Charge with Turbocharger to Rich-
Burn SI Engine
500 – 8000
146.4-279.7
204-2,026
NSCR to Rich-Burn Engine SI Engine
500 – 8000
35.4-330.7
319-1,647
Low Emission Combustion to Medium Speed
Rich-Burn or Lean-Burn SI Engine
500 – 8000
15.6-1,947.7
464-629
Low Emission Combustion to Low Speed Rich-
Burn or Lean-Burn SI Engine
500 – 8000
639.2-4,052.3
991-2,575
Automatic A/F control to Lean-Burn SI Engine
550 - 11000
98.8-169.9
427-2,000
Electronic Ignition to Lean-Burn SI Engine
550 - 11000
15.9-32.0
652-1,556
A/F + Electronic Ignition to Lean-Burn SI Engine
550 - 11000
112.4-197.4
477-1,961
SCR to Lean-Burn SI engine
550 - 11000
457.5-1,451.0
641-3,542
Electronic Injection to Diesel Engine
500 – 8000
15.9-101.8
482-1,012
SCR to Diesel Engine
500 – 8000
308.5-1,264.1
899-4,536
Electronic Injection to Dual-Fuel Engine
700 – 8000
15.9-32.0
627-1,288
SCR to Dual-Fuel Engine
700 – 8000
333.3-1,264.1
1,165-4,745
Low-Emission Combustion to Dual-Fuel Engine
700 – 8000
941.2-5,228.8
2,928-5,961
Another reference document that the Illinois EPA relied upon in the development of this
regulatory proposal is “Stationary Reciprocating Internal Combustion Engines .
10
It discusses
the uncontrolled and controlled levels of NO
x
emissions from RICE and the cost effectiveness of
LEC. U.S. EPA obtained information on LEC costs from several sources. The total capital cost,
annual operating cost, and cost effectiveness projections in Table 5-2 are based on actual costs
for several LEC retrofits obtained from one engine manufacturer and one third party LEC
vendor. Other inputs include uncontrolled NO
x
emissions of 16.8 g/bhp-hr, controlled emissions
of 2.0 g/bhp-hr, and capacity utilization of 7,000 operating hours per year (prorated for the five
months of the ozone season). In most respects, the analysis was conducted according to the
Electronic Filing - Received, Clerk's Office, December 20, 2007

29
methodology of the 1993 ACT document. The cost data was reported in 1990 dollars and the
Illinois EPA adjusted the cost data to 2004 dollars based on the CPI.
Table 5-2
Costs and Cost Effectiveness of LEC Controls in 2004 Dollars
10
Engine
NO
x
Reduction (tons)
Cost Effectiveness ($/ton NO
x
)
Size,
(bhp)
Total
Capital
Annual
Cost
Annual
O3 Season
Annual
O3 Season
80
$231,000
$59,100
9
4
7,730
18,510
240
242,000
61,400
27
11
2,680
6,430
500
259,000
65,200
57
24
1,360
3,270
1,000
293,000
72,400
114
48
750
1,820
2,000
359,000
86,900
228
95
450
1,090
4,000
493,000
116,000
457
190
300
730
6,000
627,000
146,000
685
285
250
610
8,000
760,000
175,000
914
381
230
550
5.2 Cost Effectiveness of Controls on Turbines
The Illinois EPA relied on cost data contained in U.S. EPA’s ACT
9
for determining cost
effectiveness estimates for control of turbines. A compilation of control costs complied by
STAPPA/ALAPCO
7
is also summarized here. U.S. EPA’s ACT document describes in detail the
capital cost and cost effectiveness of various controls for turbines based on 1990 dollars. The
1990 dollar estimates have been adjusted to 2004 dollars throughout this discussion as described
in Section 5.1. The cost effectiveness of two types of controls for smaller turbines of 3.3 MW
varies from $2,645 per ton of NO
x
on an annual basis removed for steam injection to $3,005 per
ton of NO
x
removed for water injection control. For dry low-NO
x
combustion, cost effectiveness
was $1,532 per ton of NO
x
removed for a four MW gas-fired turbine.
STAPPA/ALAPCO prepared a document which summarizes the cost of controlling various sizes
of turbines based on the cost information contained in the ACT for the turbines. The cost
information in the STAPPA/ALAPCO document
7
is reported in 1993 dollars. Table 5-3 shows
the cost effectiveness of controlling 5 to 25 MW turbines operating 8,000 hours annually.
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30
Table 5-3
Cost Effectiveness for Various NO
x
Controls Systems for Turbines
7
Type of Control
Turbine
Size
(MW)
Total
Capital Cost
(thousands of 2004
dollars)
Cost Effectiveness
(2004 dollars/ ton of
NO
x
removed)
Water Injection for Gas-Fired
5 – 25
711-1,490
902-2,327
Water Injection for Oil-Fired
5 – 25
745-1,582
732-1,699
Steam Injection for Gas-Fired
5 – 25
928-2,105
993-2,614
Steam Injection for Oil-Fired
5 – 25
974-2,261
680-1,699
Low-NOx Combustor for Gas-
Fired
5 – 25
630-1,438
314-1,046
SCR for Gas-Fired
5 – 25
748-2,013
1,606-3,203
SCR for Oil-Fired
5 – 25
748-2,018
1,072-2,039
The Illinois EPA believes that the impacted sources will meet the proposed limits by installing
combustion controls. Rich burn engines will install NSCR and lean burn engines will install LEC
technologies to comply the regulations. The Illinois EPA believes that retrofit costs of
controlling sources at proposed levels will be $319 to $2,575 per ton of NO
x
reduced for RICE
and $314 to $3,005 per ton of NO
x
reduced for turbines in 2004 dollars.
It should be recognized that reducing NO
x
emissions by combustion controls on RICE and
turbines may increase carbon monoxide emissions in some cases. The Illinois EPA believes that
the increases in CO emissions are not significant from an air quality perspective, but may be
high enough to trigger Prevention of Significant Deterioration (PSD) permitting requirements in
some cases.
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31
6.0 Existing and Proposed Regulations
6.1 Existing Illinois Regulations
In Part 217 of 35 Ill. Adm. Code, Illinois provides NO
x
limitations for certain fuel combustion
emission units, such as boilers and certain process emission units which use or produce nitric
acid. On July 20, 2007, the Board adopted 35 Ill. Adm. Code 217, Subpart Q, “Stationary
Reciprocating Internal Combustion Engines and Turbines,” in which it regulated the NOx
emissions from 28 large RICE engines identified by U.S. EPA under the NOx SIP Call Phase II
(R07-18). New Subpart Q contained provisions for NOx concentration levels, emissions
averaging plans, monitoring, testing, compliance, dates, recordkeeping, and reporting. Larger
non-EGU turbines greater than or equal to 250 mmBtu/hr capacities are regulated under 35 Il.
Adm. Code 217, Subpart U, which is the NO
x
SIP Call trading program for such units. The
owner or operator of any new RICE and turbines is subject to new source review requirements
and must meet any applicable New Source Performance Standards (NSPS) set by U.S. EPA.
Currently, there are no regulations to control NO
x
emissions from smaller turbines less than 250
mmBtu/hr capacities, nor are there regulations to control NOx emissions from reciprocating
engines not subject to the new Subpart Q.
6.2 Other States’ Regulations
Tables 6-1 and 6-2 contain summaries of the NO
x
control requirements in other states. Several
states have promulgated rules limiting NO
x
emissions from RICE. According to the
STAPPA/ALAPCO document
7
, Connecticut, Louisiana, New Jersey, New York, Rhode Island,
and Texas have established NOx limits based on the RACT requirements for NAAs. Typical
NO
x
RACT limits are 1.5 – 3.0 g/bhp-hr (105-210 ppm) for gas-fired rich- and lean-burn
engines, and 8-9 g/bhp-hr (584-660) for oil-fired lean-burn engines. In California, NO
x
emissions limits for RICE are based on the BART NO
x
limits. NO
x
limits in California’s
Ventura Bay Area County Air Quality Management Districts (AQMD), Santa Barbara County
AQMD, and South Coast AQMD are more stringent than RACT, and are set at 0.6 - 1.9 g/bhp-hr
(42 - 133 ppm) for lean-burn engines, 0.4 – 0.8 g/bhp-hr (28 - 70 ppm) for rich-burn engines, and
1.1 - 8.4 g/bhp-hr (80-613 ppm) for diesel engines. The size cut-off for engines to apply controls
varies from 50 bhp to 500 bhp in the states mentioned above.
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32
Table 6-1
NOx Control Requirements for RICE in Other States
State
Engine Size
Controlled (HP)
Control Level (g/hp-hr)
Gas-fired Rich Burn
Gas-fired Lean Burn
Compression Ignited
Liquid Fired
Texas
11
500 and greater
2 g/hp-hr (146 PPM)
under all operating
conditions
2 g/hp-hr (146 PPM)* at full load, 5
g/hp-hr (365 PPM) at 80-100% load
for new SI or CI dual fuel engines
manufactured after June 18, 1992; 5
g/hp-hr for older units at all loads, 8
g/hp-hr (584 PPM) at 80-100% load
11 g/hp-hr (803 ppm)
Indiana
12
NO
x
SIP Call
NO
x
SIP Call
NO
x
SIP Call
NO
x
SIP Call
Connecticut
13
3 MMBtu/hr
(1175 HP)
2.5 g/hp-hr (183 PPM)
_
8 g/hp-hr (584 ppm)
Alabama
14
NO
x
SIP Call
NO
x
SIP Call
NO
x
SIP Call
NO
x
SIP Call
New York
15
200 HP in Severe
Ozone Area and
400 HP in rest of
State
2 g/hp-hr (146 PPM)
through March 31, 2005
& 1.5 g/hp-hr (110 PPM)
after April 1, 2005
3 g/hp-hr (220 PPM) through March
31, 2005 & 1.5 g/hp-hr (110 PPM)
after April 1, 2005
9 g/hp-hr (657 ppm)
through March 31, 2005
& 2.3 g/hp-hr (168 ppm)
after April 1, 2005
New Jersey
16
500 HP
1.5 g/hp-hr (110 PPM)
2.5 g/hp-hr (182 ppm)
8 g/hp-hr (584 ppm)
Pennsylvania
17
153 ton
NOx/Season
1.5 g/hp-hr (110 PPM)
for >2,400
HP
3 g/hp-hr (220 PPM) for >
2,400
HP
2.3 g/hp-hr (168 ppm)
for >4,400
HP
Maryland
18
N.G. Pipeline
engines > 15%
capacity factor
Limits of 300 lb/hr for a
facility with 5 or less
engines, and 566 lb/hr
for a facility with more
than 5 engines
Antelope Valley Air
Quality Management
District(AVAQMD)
19
50 HP stationary
and 100 HP for
portable
Electric motor, 36 ppm
for stationary and 80
ppm for portable
Up to 770 ppm for >100
HP but less than 400 HP;
535 ppm for >
400HP
San Joanquin Valley
Unified Air Pollution
Control District
(SJVUAPCD)
20
50 HP
50 ppm or 90% red. For
waste gas/field gas
engine and 25 ppm or
96% red. for others
75 ppm or 85% red for two stroke
gaseous fuel < 100HP engine and
65 ppm for other
65ppm or 90% reduction
El Dorado County
Air Pollution Control
District
(EDCAPCD)
21
50 HP
25 ppm to 50 ppm based
on compliance dates
65 ppm to 125 ppm based on
compliance date
600 ppm to 700 ppm
based on compliance
date
IEPA Proposed
500 HP
150 ppm
210 ppm except 365 for
Worthington engines
660 ppm
Note:
1) NO
x
SIP Call requires 82 to 90 percent control on large engines that emitted one ton of NOx in any
1995 ozone season day.
22
2) 1 g/hp-hr = 73 ppm conversion factor was used to convert g/hp-hr to ppmv at 15 percent O
2
on a dry
basis.
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33
Table 6-2
NO
x
Control Requirements for Turbines in Other States
State
Turbine Size Controlled (HP)
Control Level
Texas
11
500 HP (0.37 MW)
3 g/hp-hr (0.82 lb/mmBtu) (220 ppm)
Indiana
12
250 mmBtu/hr (≈ 25 MW)
Budget allowances under NOx Emissions Trading
Program
Up to 100 mmBtu/hr (≈ 10 MW)
55 ppm for Gas-fired, 75 ppm for Oil-fired
Connecticut
13
< 100 mmBtu/hr
0.9 lb/mmBtu (224 to 245 ppm)
New York
15
10 mmBtu/hr (≈ 1 MW)
RACT, For Simple Cycle 50 ppm for gas, 100
ppm for oil; for combined cycle 42 ppm for gas
and 65 ppm for oil
New Jersey
16
30 mmBtu/hr (≈ 3 MW)
For simple cycle gas-fired 0.2 lb/mmBtu (50
PPM), for oil-fired 0.4 lb/mmBtu (109 ppm); for
combined cycle gas-fired 0.15 lb/mmBtu (37
ppm), and for oil-fired 0.35 lb/mmBtu (95 ppm)
Maryland
18
Capacity factor 15%
42 ppm for gas burning and 65 ppm for oil burning
South Coast Air
Quality
Management
District
(SCAQMD)
23
0.3 MW
9 ppm to 25 ppm depending on the size and type
IEPA Proposed
3.5 MW
42 ppm for gas-fired and 96 ppm for oil-fired
6.3 Proposed Illinois Regulations
The Illinois EPA considered other states NO
x
regulations, STAPPA/ALAPCO recommendations,
and U.S. EPA guidance documents in its proposal to establish reasonable levels of NO
x
controls
for reciprocating engines and turbines in Illinois. Size thresholds for the units affected by the
proposed regulation are based on their PTE for NO
x
on an annual basis. The Illinois EPA is
proposing to control NO
x
emissions from sources in the nonattainment area for 8-hr ozone
NAAQS that have a PTE of 100 TPY or more of NO
x
aggregated from all the affected units at
the source. The proposed regulation applies to RICE of 500 bhp capacities and above, and to
stationary turbines of capacities equal to or greater than 3.5 MW located at these 100 TPY
sources. The proposed amendments do not apply to emergency standby engines; engines used in
research and testing for the purposes of performance verification and testing of engines;
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34
engines/turbines used for agricultural purpose; and certain portable engines. Sources can avoid
the proposed control requirement by staying below source-wide NO
x
emissions of 100 TPY from
all affected units or if the total operating rate for all affected engines is less than eight million
bhp per year and all affected turbines is less than 20 thousand MW-hr per year.
The Illinois EPA relied upon the U.S. EPA’s ACT
8,9
, and STAPPA/ALAPCO guidance
documents
7
to propose levels of controls for various types of units. All of the proposed controls
levels are based on the retrofit techniques available for each category of affected unit. From
review of the ACT and guidance documents and the comments received from the affected
sources during outreach, the Illinois EPA determined that LEC controls on Worthington engines
can achieve NO
x
emissions of 308-420 ppmv as compared to other spark-ignited lean burn
engine that can achieve NO
x
emissions below 210 ppmv. Therefore, an average limit of 365
ppmv is proposed for Worthington engines. Although, post-combustion controls, such as SCR,
are available and can achieve the greatest reductions, the proposed control levels do not require
SCR as a compliance method.
Section 182(f) of the CAA introduced the requirement for existing major stationary sources of
NO
x
in NAAs to install and operate RACT to control NO
x
emissions. The NO
x
control levels
proposed in this submittal are considered reasonable, attainable, and cost-effective. The NO
x
emissions levels are prescribed in ppmv corrected to 15 percent O
2
on a dry basis. The NO
x
limits for engines are 150 ppmv for spark-ignited rich-burn, 210 ppmv for spark-ignited lean-
burn, 365 ppmv for Worthington engines and 660 ppmv for diesel engines and for turbines the
NOx limits are 42 ppmv for gas-fired and 96 ppmv for liquid-fired. An owner or operator may
comply with the control requirements by averaging the emissions of affected units that
commenced operation on or before January 1, 2002, unless the unit is a replacement unit, in
which case such a unit may be included even if it commenced operation after January 1, 2002.
Compliance with the emission limits will be determined on both an ozone season (May 1, to
September 30) and an annual (January 1 to December 31) basis each year. For units included in
an averaging plan, and units using Continuous Emissions Monitoring Systems (CEMS),
compliance with the emission limits must be demonstrated each year. For all other units,
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35
compliance will be demonstrated on a periodic basis using stack tests and portable monitoring
systems.
The Illinois EPA believes that most engines and turbines can reasonably achieve the proposed
NO
x
emission limitations. However, some engines or turbines may have difficulty in achieving
the proposed limits. Therefore, The Illinois EPA is also proposing a NO
x
emissions averaging
option to assist sources in complying with the regulations. To take advantage of this flexible
approach, a company must submit an emissions averaging plan which lists all of its units that
will be included under this option. The total sum of the
actual
NO
x
emissions from each engine
or turbine in an averaging plan (based on stack tests results and annually monitored data) must
be less than the total sum of the
allowable
NO
x
emissions from those engine and turbines in the
averaging plan based on the respective control level proposed. If sources, which are using an
averaging plan, replace their fuel combusting units with electric motors, the allowable NO
x
emissions from the affected units that were replaced should be used in the averaging calculations
and the actual NO
x
emissions for the electric motors are considered zero. The allowable NO
x
emissions from the electric motor is determined by multiplying the total bhp-hrs generated by the
motor (bhp rate of motor x operating hours) by the allowable NO
x
emission rate of the replaced
unit in lbs/mmBtu and converting the pounds of NO
x
emissions using the factor of 0.00077
mmBtu/bhp-hr. The conversion factor was derived by using a standard conversion factor of one
bhp-hr equals to 2545.1 Btu and engine thermal efficiency of 33%.
For a replacement unit which is not electric, the allowable NO
x
emission rate to be used in the
averaging plan prior to its compliance date will be the higher of the applicable uncontrolled NO
x
emission rate from the U.S. EPA’s AP-42 document or the actual NO
x
emission rate as
determined by testing or monitoring. On and after the applicable compliance date for the
replacement unit, the allowable NO
x
emission rate will be the allowable applicable NO
x
emission
concentration limit specified in the proposed rule.
For a unit that is replaced with purchased power, the allowable NO
x
emission rate will be the
applicable NO
x
emissions concentration specified in the proposed rule. The actual hours of
operation to be used will be the annual hours of operation for the replaced unit averaged over the
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36
three-year period prior to the date of purchasing power. Purchased power units may be included
in an emission averaging plan for no more than five years.
Tables 6-3 and 6-4 provide examples of how the proposed emissions averaging plan will work.
Table 6-3 shows an example plan which includes four engines and one turbine. In this example,
actual NO
x
emissions of 812,965 pounds are greater than the allowable NO
x
emissions of
804,666 pounds; therefore, the source is not in compliance with the proposed rule. Table 6-4
shows that by adjusting the operating hours of each engine and turbine, the actual NO
x
emissions
of 783,316 pounds, therefore the company achieves compliance without any penalty in fuel
consumption and total bhp-hrs in a year.
Table 6-3
Example of Averaging Plan-Case 1
Engines
Rated
bhp
Allow.
NO
x
Limit
(ppm)
Actual
NO
x
Limit
(ppm)
Fuel Use
(mmBtu/yr)
Hours
of
Oper.
Bhpbhp-
hrs x10
3
Allow. NO
x
(lb)
Actual NO
x
(lb)
Engine 1
3,000
150
175
127,500
5,000
15,000
70,456
82,199
Engine 2
3,500
210
220
148,750
5,000
17,500
115,078
120,558
Engine 3
4,000
660
700
170,000
5,000
20,000
436,121
462,553
Engine 4
4,500
210
150
191,250
5,000
22,500
147,958
105,684
Turbine 5
5,361
42
50
227,843
5,000
26,805
35,253
41,968
Total
865,343
25,000
101,805
804,866
812,962
Table 6-4
Example of Averaging Plan-Case 2
Engines
Rated
bhp
Allow.
NO
x
Limit
(ppm)
Actual
NO
x
Limit
(ppm)
Fuel Use
(mmBtu/yr)
Hours
of
Oper.
Bhp-hrs
x10
3
Allow. NO
x
(lb)
Actual NO
x
(lb)
Engine 1
3,000
150
175
114,750
4,500
15,000
63,410
73,979
Engine 2
3,500
210
220
133,875
4,500
17,500
103,570
108,502
Engine 3
4,000
660
700
156,400
4,600
20,000
401,231
425,548
Engine 4
4,500
210
150
232,475
6,078
22,500
179,851
128,465
Turbine 5
5,361
42
50
227,843
5,000
26,805
35,253
41,968
Total
865,343
24,678
101,805
783,316
778,463
An owner or operator of any affected engine or turbine located in Cook, DuPage, Grundy, Kane,
Kendall, Lake, McHenry, Will, Jersey, Madison, Monroe, Randolph, or St. Clair counties (NAA
Electronic Filing - Received, Clerk's Office, December 20, 2007

37
counties) are required to comply with the rule by May 1, 2010. This compliance date, although
later than the date required by U.S. EPA for NO
x
RACT, was chosen to allow companies the
ability to schedule equipment installations in a timely manner after promulgation of this
proposed rule.
The proposed regulations provides for the limited use of CAIR NO
x
allowances to comply with
the emission limitations. The use of CAIR NO
x
allowances are limited to documented
unforeseen or anomalous operating scenarios inconsistent with historical operations for a
particular ozone season or calendar year. This compliance option cannot be used more than
twice in any five-year rolling period. The owner or operator shall surrender one NO
x
allowance
for each ton or portion of a ton of NO
x
emissions on an annual basis by which actual emissions
exceed allowed emissions.
An owner or operator of an engine or a turbine subject to the proposed control limits shall
perform a compliance performance test once every five years to demonstrate compliance with
the rule. All affected units must be tested once every five years thereafter. Section 217.394 of
the proposal provides methods and procedures for testing and monitoring of the performance of
an affected unit. The test methods provided are approved by U.S. EPA as set forth in 40 CFR
60.
Electronic Filing - Received, Clerk's Office, December 20, 2007

38
7.0 Potentially Affected Sources
To determine potentially affected engines and turbines, the Illinois EPA reviewed its 2004
inventory of RICE and turbines. The Illinois EPA identified a total of 541 RICE and 220
turbines located in the NAAs that have the potential to be affected by the proposed regulations.
Some of these units will be regulated under the new Subpart Q. A list of potentially impacted
sources is included in Attachment A of this TSD.
Current Illinois regulations do not require sources to obtain permits to operate RICE with a
capacity of less than 1,500 bhp. Therefore, the Illinois NOx inventory does not include all the
engines from 500 to 1,500 bhp that may be affected by this proposal. To identify potentially
affected sources and to estimate NO
x
emissions reductions from sources, with smaller engines,
the, the Illinois EPA, with the assistance of the Department of Commerce and Economic
Opportunity (DCEO), conducted a statewide survey of industries and businesses and mailed
10,025 survey forms to determine how many engines in the 500 to 1,500 bhp size range are in
Illinois. Out of 10,025 surveys, only 458 were returned and, of those, only 8 reported having
RICE in the range of 500 to 1,500 bhp. Assuming the same proportion of affected engines per
number of responses applies to those that did not respond to the survey, the Illinois EPA
estimates that there are approximately 175 units that have the potential to be affected by the
proposed rule. The Illinois EPA further assumed that many of these units would qualify for
exemptions and therefore, only approximately 8 engines would be impacted by this proposal.
Table 7-1 summarizes the number of impacted sources estimated by the Illinois EPA that are less
than 1,500 bhp.
Table 7-1
Number of Affected Sources
Unit Type
Potentially Affected
Impacted
Illinois EPA Permitted IC Engines
541
55
Turbines
220
58
IC Engines
500 bhp & < 1,500 bhp
79
8
Total
840
121
Electronic Filing - Received, Clerk's Office, December 20, 2007

39
8.0 NO
x
Emissions Reductions
As described in Section 7 the Illinois EPA estimated that the total 2004 NO
x
emissions from the
55 RICE and 58 turbines potentially affected by this proposal to be 2,514 TPY and 1,235 tons
per ozone season. The Illinois EPA applied an 82 percent control level to gas-fired engines, 25
percent control efficiency to diesel engines, and 60 percent control efficiency to turbines to
estimate NO
x
emissions reductions from the proposed rule. No control was applied to a turbine
which is subject to NSPS for NO
x
emissions. The proposed rule will achieve estimated NO
x
emissions reductions from affected sources of 1,669 TPY and 814 tons per ozone season from
RICE in the Illinois EPA’s inventory and turbines greater than 3.5 MW as shown in Table 8-1.
Table 8-1
Estimated NO
x
Emissions Reductions from Affected RICE
Uncontrolled NO
x
NO
x
Emissions Reductions
Year
(TPY)
(tons/season)
(TPY)
(tons/season)
Illinois EPA
Permitted RICE
1,198
528
983
433
Turbines
1,316
706
686
381
Small units
593
247
486
203
Total
3,107
1,481
2,155
1,017
To estimate NO
x
emissions reductions from the smaller RICE, between 500 bhp and 1,500 bhp,
the Illinois EPA assumed the average capacity of the impacted RICE to be 1,000 bhp and the
estimated operating schedule to be 4,000 hours per year. At a NO
x
emission rate of 16.8 g/bhp-
hr, the estimated 2004 NOx emissions were determined to be 593 tons NO
x
per year and 247
tons per ozone season.. At a control efficiency of 82 percent, the NOx reduction from these
engines will be 486 TPY and 203 tons per ozone season. Table 8-1 shows the estimated NO
x
emissions reductions from “small units” with their corresponding total NO
x
emissions
reductions. As shown in Table 8-1, this proposal will provide NO
x
emissions reductions of
2,155 TPY and 1,017 tons per ozone season when fully implemented in 2010.
Electronic Filing - Received, Clerk's Office, December 20, 2007

40
9.0 Summary
This TSD presents the rationale, the documentation, and the methodology used by the Illinois
EPA in the development of its proposed regulation to control NO
x
emissions from reciprocating
internal combustion engines and turbines. NO
x
emissions are a contributor to fine particulate
matter and ozone levels in areas of Illinois that are designated as nonattainment areas for these
pollutants. The proposed regulation is being submitted to the Illinois Pollution Control Board to
satisfy the requirements of the CAA to implement RACT on these source categories. Illinois
EPA is in the process of developing regulations to control other NO
x
source categories, as
needed, to satisfy the CAA requirement for NO
x
RACT.
The Illinois EPA is proposing to control NO
x
emissions from sources in the NAA that have a
PTE of 100 TPY or more of NO
x
aggregated from all the affected units at the source. The
proposed regulation applies to RICE of 500 bhp capacities and above, and to stationary turbines
of capacities equal to or greater than 3.5 MW. The proposed regulation does not apply to
emergency standby engines; engines used in research and testing for the purposes of
performance verification and testing of engines; engines/turbines used for agricultural purposes;
and certain portable engines. Sources can avoid the proposed control requirement by staying
below source-wide NO
x
emission levels of 100 TPY from all affected units or by operating all
affected engines less than eight million bhp-hr/year and all affected turbines less than 20,000
MW-hr/year.
All affected engines and turbines are required to comply with the rule by May 1, 2010. From
outreach discussions, this approach was recommended to help alleviate anticipated equipment
and material delays, as well as demands on technical staffing needed for installation and testing
of new controls, without sacrificing critical emission reductions.
The Illinois EPA proposal includes a NO
x
emissions averaging option to assist sources in
complying with the regulations. To take advantage of this flexible approach, a company must
submit an averaging plan which lists all of its units that will be included under this option. The
total sum of the actual NO
x
emissions from each engine or turbine in an averaging plan (based on
Electronic Filing - Received, Clerk's Office, December 20, 2007

41
stack tests results and annually monitored data) must be less than the total sum of the allowable
NO
x
emissions from those engine and turbines in the averaging plan based on the respective
control level proposed.
The proposed regulation will impact approximately 63 RICE and 58 turbines in Illinois when
fully implemented in 2010. When fully implemented, the proposed rule will reduce the NO
x
emissions from RICE by approximately 1,469 TPY and 636 tons per ozone control season at a
cost effectiveness of $319 to $2,575 per ton of NO
x
(in 2004 dollars). Emissions from gas
turbines will be reduced by approximately 686 TPY and 381 tons per ozone season at a cost
effectiveness of $314 to $3,005 per ton of NO
x
(in 2004 dollars).
Electronic Filing - Received, Clerk's Office, December 20, 2007

42
10.0 References
1. National Ambient Air Quality Standards for Ozone, 62
FR
38855, July 18, 1997, (Ozone
Standards).
2. National Ambient Air Quality Standards for Particulate Matter, 62
FR
38652, July 18, 1997,
(PM
2.5
Standards).
3. Air Quality Designations and Classifications for fine Particles (PM
2.5
) National Ambient Air
Quality Standards, 70
FR
943, January 5, 2005.
4. 8-hour Ozone National Ambient Air Quality Standards, 69
FR
23858, April 30, 2004.
5. Final Rule to Implement the 8-Hour Ozone National Ambient Air Quality Standard, 70
FR
71612, November 29, 2005.
6. Clean Air Fine Particle Implementation; Final Rule, 40 C
FR Part 51
, April 25, 2007
.
7. Controlling Nitrogen Oxides Under the Clean Air Act: A Menu of Options, July 1994, State
and Territorial Air Pollution Program Administrators/Association of Local Air Pollution
Control Officials.
8. Alternative Control Techniques Document--NOx Emissions from Stationary Reciprocating
Internal Combustion Engines EPA-453/R-93-032, July 1993, U.S. EPA, OAQPS, RTP, NC
27711.
9. Alternative Control Techniques Document – NOx Emissions from Stationary Gas Turbines,
EPA-453/R-93-007, January 1993, U.S. EPA, OAQPS, Research Triangle Park, NC 27711
10. Stationary Reciprocating Internal Combustion Engines, Updated Information on NOx
Emissions and Control Techniques, Revised Final Report, EPA Contract No. 68-D-026,
Work Assignment No. 2-28,EC/R Project No. ISD-228, September 1, 2000
.
11. Texas Administrative Code. Title 30, Rule 106.512: Stationary Engines and Turbines
12. Indiana Department of Environmental Management, Office of Air Quality, Section 9.326
IAC 10-5. Rule 5 Nitrogen Oxide Reduction Program for Internal Combustion Engines
(ICE).
13. Document Prepared by the State of Connecticut, Department of Environmental Protection.
Sec. 22a-174-22 Control of Nitrogen Oxides Emissions
.
14. Alabama Department of Environmental Management. Air Division, Chapter 335-3-8,
Nitrogen Oxides Emissions.
Electronic Filing - Received, Clerk's Office, December 20, 2007

43
15. New York State, Department of Environmental Conservation Rule and Regulations, Subpart
227.2, Reasonable Available Control Technology (RACT) for Oxides of Nitrogen (NOx).
16. New Jersey State Department of Environmental Protection, New Jersey Administrative
Code Title 7, Chapter 27, Subchapter 19: Control and Prohibition of Air Pollution from
Oxides of Nitrogen.
17. Pennsylvania Department of Environmental Protection, Air Quality Regulations, Small
Source of NOx Cement Kilns and Large Internal Combustion Engines, 25 PA Code CHS
121,129 and 145.
18. Code of Maryland Regulations. Title 26 Department of the Environment. Subtitle 11 Air
Quality, Chapter 09: Control of Fuel-Burning Equipment, Stationary Internal Combustion
Engines, and Certain Fuel-Burning Installation.
19. Antelope Valley Air Quality Management District. Rule 1110.2: Emissions from Stationary,
Non-Road & Portable Internal Combustion Engines.
20. San Joaquin Valley Unified Air Pollution Control District Rule 4702: Internal Combustion
Engines – Phase 2.
21. El Dorado County Air Pollution Control District Rule 233: Stationary Internal Combustion
Engines.
22. Interstate Ozone Transport: Response to Court Decisions on the NOx SIP Call, NOx SIP
Call Technical Amendments, and Section 126 Rules; Final Rule. 69 FR 21603, April 21,
2004.
23. South Coast Air Quality Management District, Rule 1134 – Emissions of Oxides of
Nitrogen from Stationary Gas Turbines.
Electronic Filing - Received, Clerk's Office, December 20, 2007

44
Attachment A
List of Impacted RICE and Turbines
Electronic Filing - Received, Clerk's Office, December 20, 2007

45
List of Impacted RICE
Id Number
Plant Name
Emission
Point
No. of
Units
031600ATR
International Malting Company - United States
0011
2
031600ATR
International Malting Company - United States
0014
2
031600ATR
International Malting Company - United States
0012
2
031600CEV
University of Illinois At Chicago
0009
1
031600CEV
University of Illinois At Chicago
0010
1
031600CEV
University of Illinois At Chicago
0011
2
043065ADG
Nicor Gas
0003
4
097200ABC
Bio Energy (Illinois) LLC
0001
1
097200ABC
Bio Energy (Illinois) LLC
0002
1
097200ABC
Bio Energy (Illinois) LLC
0003
1
097200ABC
Bio Energy (Illinois) LLC
0004
1
097200ABC
Bio Energy (Illinois) LLC
0005
1
097811AAC
Naval Training Center
0050
2
097811AAC
Naval Training Center
0095
5
097811AAC
Naval Training Center
0055
6
097811AAC
Naval Training Center
0097
2
097811AAC
Naval Training Center
0108
2
097811AAC
Naval Training Center
0107
2
097811AAC
Naval Training Center
0106
2
097811AAC
Naval Training Center
0049
1
111816AAA
ANR Pipeline Co
0010
1
111816AAA
ANR Pipeline Co
0022
1
111816AAA
ANR Pipeline Co
0024
1
111816AAA
ANR Pipeline Co
0025
1
111816AAA
ANR Pipeline Co
0030
1
111816AAA
ANR Pipeline Co
0029
1
163050AAD
Milam Recycling and Disposal Facility
0012
3
197800ABU
Trunkline Gas Co
0001
5
Total RICE
55
Electronic Filing - Received, Clerk's Office, December 20, 2007

46
List of Impacted Turbines
Id Number
Plant Name
Emission
Point
No. of
Units
031003ADA
Alsip Paper Condominium Assn
0002
1
197817AAA
Natural Gas Pipeline Co of America
0016
9
197817AAA
Natural Gas Pipeline Co of America
0020
10
031600AMJ
Midwest Generation LLC
0003
11
031600GKE
Calumet Peaking Facility
0001
8
097200ABB
Zion Energy Center
0001
3
197800AAA
Exxon Mobil
0043
1
197808AAG
Elwood Energy Facility
0007
3
197899AAC
PPL University Park LLC
0001
1
197899AAC
PPL University Park LLC
0002
1
197899AAC
PPL University Park LLC
0003
1
197899AAC
PPL University Park LLC
0004
1
197899AAC
PPL University Park LLC
0005
1
197899AAC
PPL University Park LLC
0006
1
197899AAC
PPL University Park LLC
0007
1
197899AAC
PPL University Park LLC
0008
1
197899AAC
PPL University Park LLC
0009
1
197899AAC
PPL University Park LLC
0010
1
197899AAC
PPL University Park LLC
0011
1
197899AAC
PPL University Park LLC
0012
1
Total
Turbines
58
Electronic Filing - Received, Clerk's Office, December 20, 2007

Agency Analysis of Economic and
Budgetary Effects of Proposed Rulemaking
Agency:
Illinois Pollution Control Board
Part/Title:
Permits And General Provisions (35 Ill. Adm. Code Part 201.146)
Illinois Register Citation: _______________________________
Please attempt to provide as dollar-specific responses as possible and feel free to add any relevant
explanation.
1.
Anticipated effect on State expenditures and revenues.
(a)
Current cost to the agency for this program/activity.
$0 per year
(approximately)
(b)
If this rulemaking will result in an increase or decrease in cost, specify the fiscal
year in which this change will first occur and the dollar amount of the effect.
2010, the annual cost increase of approx. $50,000 per year
(c)
Indicate the funding source, including Fund and appropriation lines, for this
program/activity.
Clean Air Act Permit Program Fund (CAAPP)
(d)
If an increase or decrease in the costs of another State agency is anticipated,
specify the fiscal year in which this change will first occur and the estimated
dollar amount of the effect.
N/A
(e)
Will this rulemaking have any effect on State revenues or expenditures not
already indicated above?
No
2.
Economic effect on persons affected by the rulemaking:
(a)
Indicate the economic effect and specify the persons affected:
Positive ___ Negative ____ No effect _
X
__
Persons affected: __owners and operators of certain stationary internal
combustion engines and turbines__ ____
Dollar amount per person: _
0
__
Total statewide cost: ___
0
__
_____
Electronic Filing - Received, Clerk's Office, December 20, 2007

(b)
If an economic effect is predicted, please briefly describe how the effect will
occur. _
N/A
__ ____
(c)
Will the rulemaking have an indirect effect that may result in increased
administrative costs?
No
Will there be any change in requirements such
as filing, documentation, reporting or completion of forms?
The rulemaking should have no indirect effect that may result in increased
administrative costs.
Electronic Filing - Received, Clerk's Office, December 20, 2007

Agency Analysis of Economic and
Budgetary Effects of Proposed Rulemaking
Agency:
Illinois Pollution Control Board
Part/Title:
Definitions and General Provisions (35 Ill. Adm. Code Part 211)
Illinois Register Citation: _______________________________
Please attempt to provide as dollar-specific responses as possible and feel free to add any relevant
explanation.
1.
Anticipated effect on State expenditures and revenues.
(a)
Current cost to the agency for this program/activity.
$ 0 per year
(approximately)
(b)
If this rulemaking will result in an increase or decrease in cost, specify the fiscal year in
which this change will first occur and the dollar amount of the effect.
N/A
(c)
Indicate the funding source, including Fund and appropriation lines, for this
program/activity.
N/A
(d)
If an increase or decrease in the costs of another State agency is anticipated, specify the
fiscal year in which this change will first occur and the estimated dollar amount of the
effect.
N/A
(e)
Will this rulemaking have any effect on State revenues or expenditures not already
indicated above?
No
2.
Economic effect on persons affected by the rulemaking:
(a)
Indicate the economic effect and specify the persons affected:
Positive ___ Negative ____ No effect
_ X
Persons affected: __Owners and operators of affected stationary internal combustion
engines and turbines
Dollar amount per person: __
0_
Total statewide cost: ____
0
(b)
If an economic effect is predicted, please briefly describe how the effect will occur.
N/A
Electronic Filing - Received, Clerk's Office, December 20, 2007

(c)
Will the rulemaking have an indirect effect that may result in increased
administrative costs?
No
Will there be any change in requirements such as filing,
documentation, reporting or completion of forms?
No
The rulemaking should have no indirect effect that may result in increased
administrative costs.
Electronic Filing - Received, Clerk's Office, December 20, 2007

Agency Analysis of Economic and
Budgetary Effects of Proposed Rulemaking
Agency:
Illinois Pollution Control Board
Part/Title:
Nitrogen Oxides Emissions (35 Ill. Adm. Code Part 217 )
Illinois Register Citation: _______________________________
Please attempt to provide as dollar-specific responses as possible and feel free to add any relevant
explanation.
1.
Anticipated effect on State expenditures and revenues.
(a)
Current cost to the agency for this program/activity.
$
0 per year
(approximately)
(b)
If this rulemaking will result in an increase or decrease in cost, specify the fiscal
year in which this change will first occur and the dollar amount of the effect.
2010, the annual cost increase of approx. $75,000 per year
(c)
Indicate the funding source, including Fund and appropriation lines, for this
program/activity.
Clean Air Act Permit Program Fund (CAAPP)
(d)
If an increase or decrease in the costs of another State agency is anticipated,
specify the fiscal year in which this change will first occur and the estimated
dollar amount of the effect.
n/a
(e)
Will this rulemaking have any effect on State revenues or expenditures not
already indicated above?
no
2.
Economic effect on persons affected by the rulemaking:
(a)
Indicate the economic effect and specify the persons affected:
Positive ___ Negative __
X
__ No effect _ __
Persons affected:
__owners and operators of affected stationary internal
combustion engines
Dollar amount per person:
_$314 to $3,005 average annual cost per ton of NOx
reduced__
Total statewide cost:
__$677,000 to $6,476,000_per year
Electronic Filing - Received, Clerk's Office, December 20, 2007

(b)
If an economic effect is predicted, please briefly describe how the effect will
occur.
_The cost to install and to maintain required air pollution control
equipment.
(c)
Will the rulemaking have an indirect effect that may result in increased
administrative costs? Will there be any change in requirements such as
filing, documentation, reporting or completion of forms?
The rulemaking should have no indirect effect that may result in increased
administrative costs
.
Electronic Filing - Received, Clerk's Office, December 20, 2007

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Wednesday,
April 25, 2007
Part II
Environmental
Protection Agency
40 CFR Part 51
Clean Air Fine Particle Implementation
Rule; Final Rule
Agency Information Collection Activities:
Proposed Collection; Comment Request;
PM
2.5
Ozone National Ambient Air Quality
Standard Implementation Rule; EPA ICR
No. 2258.01; Notice
Electronic Filing - Received, Clerk's Office, December 20, 2007

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20586
Federal Register
/ Vol. 72, No. 79 / Wednesday, April 25, 2007 / Rules and Regulations
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Part 51
[EPA–HQ–OAR–2003–0062; FRL–8295–2]
RIN 2060–AK74
Clean Air Fine Particle Implementation
Rule
AGENCY:
Environmental Protection
Agency (EPA).
ACTION:
Final rule.
SUMMARY:
This final action provides
rules and guidance on the Clean Air Act
(CAA) requirements for State and Tribal
plans to implement the 1997 fine
particle (PM
2.5
) national ambient air
quality standards (NAAQS). Fine
particles and precursor pollutants are
emitted by a wide range of sources,
including power plants, cars, trucks,
industrial sources, and other burning or
combustion-related activities. Health
effects that have been associated with
exposure to PM
2.5
include premature
death, aggravation of heart and lung
disease, and asthma attacks. Those
particularly sensitive to PM
2.5
exposure
include older adults, people with heart
and lung disease, and children.
Air quality designations became
effective on April 5, 2005 for 39 areas
(with a total population of 90 million)
that were not attaining the 1997 PM
2.5
standards. By April 5, 2008, each State
having a nonattainment area must
submit to EPA an attainment
demonstration and adopted regulations
ensuring that the area will attain the
standards as expeditiously as
practicable, but no later than 2015. This
rule and preamble describe the
requirements that States and Tribes
must meet in their implementation
plans for attainment of the 1997 fine
particle NAAQS. (Note that this rule
does not include final PM
2.5
requirements for the new source review
(NSR) program; the final NSR rule will
be issued at a later date.)
DATES:
This rule is effective on May 29,
2007.
ADDRESSES:
The EPA has established a
docket for this action under Docket ID
EPA–HQ–OAR–2003–0062. All
documents relevant to this action are
listed in the Federal docket management
system at
www.regulations.gov
.
Although listed in the index, some
information is not publicly available
(e.g. Confidential Business Information
or other information whose disclosure is
restricted by statute). Certain other
material, such as copyrighted material,
is not placed on the Internet and will be
publicly available only in hard copy
form. Publicly available docket
materials are available either
electronically through
www.regulations.gov or in hard copy
format at the EPA Docket Center, EPA/
DC, EPA West, Room 3334, 1301
Constitution Avenue, NW., Washington,
DC. The Public Reading Room is open
from 8:30 a.m. to 4:30 p.m., Monday
through Friday, excluding legal
holidays. The telephone number for the
Public Reading Room is (202) 566–1744,
and the telephone number for the Office
of Air and Radiation Docket and
Information Center is (202) 566–1742. A
variety of information and materials
related to the fine particle NAAQS and
implementation program are also
available on EPA’s Web site:
http://
www.epa.gov/air/particles
.
FOR FURTHER INFORMATION CONTACT:
For
general information, contact Mr.
Richard Damberg, U.S. Environmental
Protection Agency, Office of Air Quality
Planning and Standards, Mail Code
C539–01, Research Triangle Park, NC
27711, phone number (919) 54l–5592 or
by e-mail at:
damberg.rich@epa.gov
.
SUPPLEMENTARY INFORMATION:
General Information
A. Does this action apply to me?
Entities potentially regulated by this
action are State and local air quality
agencies.
B. Where can I get a copy of this
document and other related
information?
In addition to being available in the
docket, an electronic copy of this final
rule will also be available on the World
Wide Web. Following signature by the
EPA Administrator, a copy of this final
rule will be posted at
http://
www.epa.gov/particles/actions.html
.
C. How is the preamble organized?
I. Background
II. Elements of the Clean Air Fine Particle
Implementation Rule
A. Precursors and Pollutants Contributing
to Fine Particle Formation
B. No Classification System
C. Due Dates and Basic Requirements for
Attainment Demonstrations
D. Attainment Dates
E. Modeling and Attainment
Demonstrations
F. Reasonably Available Control
Technology and Reasonably Available
Control Measures
G. Reasonable Further Progress
H. Contingency Measures
I. Transportation Conformity
J. General Conformity
K. Emission Inventory Requirements
L. Condensable Particulate Matter Test
Methods and Related Data Issues
M. Improving Source Monitoring
N. Guidance Specific to Tribes
O. Enforcement and Compliance
P. Emergency Episodes
Q. Ambient Monitoring
III. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory
Planning and Review
B. Paperwork Reduction Act
C. Regulatory Flexibility Act
D. Unfunded Mandates Reform Act
E. Executive Order 13132: Federalism
F. Executive Order 13175: Consultation
and Coordination With Indian Tribal
Governments
G. Executive Order 13045: Protection of
Children From Environmental Health
and Safety Risks
H. Executive Order 13211: Actions That
Significantly Affect Energy Supply,
Distribution, or Use
I. National Technology Transfer
Advancement Act
J. Executive Order 12898: Federal Actions
To Address Environmental Justice in
Minority Populations and Low-Income
Populations
K. Congressional Review Act
L. Petitions for Judicial Review
M. Judicial Review
IV. Statutory Authority
I. Background
Fine particles in the atmosphere are
comprised of a complex mixture of
components. Common constituents
include: sulfate (SO
4
); nitrate (NO
3
);
ammonium; elemental carbon; a great
variety of organic compounds; and
inorganic material (including metals,
dust, sea salt, and other trace elements)
generally referred to as ‘‘crustal’’
material, although it may contain
material from other sources. Airborne
particles generally less than or equal to
2.5 micrometers in diameter are
considered to be ‘‘fine particles’’ (also
referred to as PM
2.5
). (A micrometer is
one-millionth of a meter, and 2.5
micrometers is less than one-seventh the
average width of a human hair.)
‘‘Primary’’ particles are emitted directly
into the air as a solid or liquid particle
(e.g., elemental carbon from diesel
engines or fire activities, or condensable
organic particles from gasoline engines).
‘‘Secondary’’ particles (e.g., sulfate and
nitrate) form in the atmosphere as a
result of various chemical reactions.
(Section II of the proposed rule included
detailed technical discussion on PM
2.5
,
its precursors, formation processes, and
emissions sources.)
The EPA established air quality
standards for PM
2.5
based on evidence
from numerous health studies
demonstrating that serious health effects
are associated with exposures to
elevated levels of PM
2.5
.
Epidemiological studies have shown
statistically significant correlations
between elevated PM
2.5
levels and
premature mortality. Other important
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effects associated with PM
2.5
exposure
include aggravation of respiratory and
cardiovascular disease (as indicated by
increased hospital admissions,
emergency room visits, absences from
school or work, and restricted activity
days), changes in lung function and
increased respiratory symptoms, as well
as new evidence for more subtle
indicators of cardiovascular health.
Individuals particularly sensitive to
PM
2.5
exposure include older adults,
people with heart and lung disease, and
children.
On July 18, 1997, we revised the
NAAQS for particulate matter (PM) to
add new standards for fine particles,
using PM
2.5
as the indicator. We
established health-based (primary)
annual and 24-hour standards for PM
2.5
(62 FR 38652).
1
The annual standard
was set at a level of 15 micrograms per
cubic meter, as determined by the 3-year
average of annual mean PM
2.5
concentrations. The 24-hour standard
was set at a level of 65 micrograms per
cubic meter, as determined by the 3-year
average of the 98th percentile of 24-hour
concentrations.
Attainment of the 1997 PM
2.5
standards is estimated to lead to
reductions in health impacts, including
tens of thousands fewer premature
deaths each year, thousands fewer
hospital admissions and emergency
room visits each year, hundreds of
thousands fewer absences from work
and school, and hundreds of thousands
fewer respiratory illnesses in children
annually. The EPA’s evaluation of the
science concluded that there was not
sufficient information to either support
or refute the existence of a threshold for
health effects from PM exposure.
2
We subsequently completed in
October 2006 another review of the
NAAQS for PM. With regard to the
primary standards, the 24-hour PM
2.5
standard was strengthened to a level of
35 micrograms per cubic meter, based
on the 3-year average of the 98th
percentile of 24-hour concentrations,
1
The original annual and daily standards for
particles generally less than or equal to 10
micrometers in diameter (also referred to as PM
10
)
were established in 1987. In the 1997 PM NAAQS
revision, EPA also revised the standards for PM
10
,
but these revised PM
10
standards were later vacated
by the court, and the 1987 PM
10
standards remained
in effect. In the 2006 NAAQS revision, the 24-hour
PM
10
standard was retained but the annual standard
was revoked. Today’s implementation rule and
guidance does not address PM
10
.
2
Environmental Protection Agency. (2004a). Air
Quality Criteria for Particulate Matter. Research
Triangle Park, NC: National Center for
Environmental Assessment—RTP, Office of
Research and Development, U.S. Environmental
Protection Agency, Research Triangle Park, NC
27711; report no. EPA/600/P–99/002aF and EPA/
600/P–99/002bF. October 2004.
and the level of the annual standard
remained unchanged.
3
Attainment of
the 2006 PM
2.5
standards is estimated to
lead to additional reductions in health
impacts, including approximately 1,200
to 13,000 fewer premature deaths each
year, 1,630 fewer hospital admissions
and 1,200 fewer emergency room visits
for asthma each year, 350,000 fewer
absences from work and school, and
155,300 fewer respiratory illnesses in
children annually.
4
In both 1997 and 2006 EPA
established welfare-based (secondary)
standards identical to the levels of the
primary standards. The secondary
standards are designed to protect against
major environmental effects of PM
2.5
such as visibility impairment, soiling,
and materials damage. The EPA also
established the regional haze regulations
in 1999 for the improvement of visual
air quality in national parks and
wilderness areas across the country.
Because regional haze is caused
primarily by light scattering and light
absorption by fine particles in the
atmosphere, EPA is encouraging the
States to integrate their efforts to attain
the PM
2.5
standards with those efforts to
establish reasonable progress goals and
associated emission reduction strategies
for the purposes of improving air quality
in our treasured natural areas under the
regional haze program.
The scientific assessments used in the
development of the PM
2.5
standards
included a scientific peer review and
public comment process. We developed
scientific background documents based
on the review of hundreds of peer-
reviewed scientific studies. The Clean
Air Scientific Advisory Committee, a
congressionally mandated group of
independent scientific and technical
experts, provided extensive review of
these assessments, and found that EPA’s
review of the science provided an
adequate basis for the EPA
Administrator to make a decision. More
detailed information on health effects of
PM
2.5
can be found on EPA’s Web site
at:
http://www.epa.gov/air/urbanair/
pm/index.html
. Additional information
on EPA’s scientific assessment
documents supporting the 1997
standards are available at
http://
www.epa.gov/ttn/oarpg/t1cd.html
;
additional scientific assessment
3
The revised fine particle NAAQS were
published on October 17, 2006 (71 FR 61144). See
EPA’s Web site for additional information:
http://
www.epa.gov/pm/index.html
.
4
Regulatory Impact Analysis for Particulate
Matter National Ambient Air Quality Standards
(September 2006), page ES–8. The mortality range
includes estimates based on the results of an expert
elicitation study, along with published
epidemiological studies.
information on the 2006 standards is
available at:
http://www.epa.gov/ttn/
naaqs/standards/pm/s
_
pm
_
cr
_
cd.html.
The EPA issued final PM
2.5
designations for areas violating the 1997
standards on December 17, 2004. They
were published in the
Federal Register
on January 5, 2005 (70 FR 944). On
April 5, 2005, EPA issued a
supplemental notice which changed the
designation status of eight areas from
nonattainment to attainment based on
newly updated 2002–2004 air quality
data (70 FR 19844; published in the
Federal Register
on April 14, 2005). A
total of 39 areas were designated as
nonattainment for the 1997 PM
2.5
standards. The population of these areas
is estimated at about 90 million (or more
than 30% of the U.S. population). Most
of these areas only violate the annual
standard, but a few violate both the
annual and 24-hour standards.
The nonattainment designation for an
area starts the process whereby a State
or Tribe must develop an
implementation plan that includes,
among other things, a demonstration
showing how it will attain the ambient
standards by the attainment dates
required in the CAA. Under section
172(b), States have up to 3 years after
EPA’s final designations to submit their
SIPs to EPA. These SIPs will be due on
April 5, 2008, 3 years from the effective
date of the designations.
Section 172(a)(2) of the Act requires
States to attain the standards as
expeditiously as practicable but within
5 years of designation (i.e. attainment
date of April 2010 based on air quality
data for 2007–2009), or within up to 10
years of designation (i.e. to April 2015)
if the EPA Administrator extends an
area’s attainment date by 1–5 years
based upon the severity of the
nonattainment problem or the feasibility
of implementing control measures.
Virtually all nonattainment problems
appear to result from a combination of
local emissions and transported
emissions from upwind areas. The
structure of the CAA requires EPA to
develop national rules for certain types
of sources which are also significant
contributors to local air quality
problems, including motor vehicles and
fuels. It also provides for States to
address emissions sources on an area-
specific basis through such
requirements as RACT, RACM, and RFP.
We believe that to attain the PM
2.5
standards, it is important to pursue
emissions reductions simultaneously on
the local, regional, and national levels.
The EPA issued the Clean Air Interstate
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Rule (CAIR)
5
on March 10, 2005 to
address the interstate transport of sulfur
dioxide and nitrogen oxide emissions
primarily from power plants. Section
110 gives EPA the authority to require
SIPs to ‘‘prohibit * * * any source or
other type of emission activity within
the State from emitting any air pollutant
in amounts which will contribute
significantly to nonattainment in, or
interfere with maintenance by, any
other State with respect to’’ any
NAAQS, and to prohibit sources or
emission activities from emitting
pollutants in amounts which will
interfere with measures required to be
included in State plans to prevent
significant deterioration of air quality or
to protect visibility (such as the
protection of 156 mandatory Federal
class I areas under the regional haze
rule
6
). CAIR employs the same
emissions trading approach used to
achieve cost-effective emission
reductions under the acid rain program.
It outlines a two-phase program with
increasingly tighter power plant
emissions caps for 28 eastern states and
the District of Columbia: SO
2
caps of 3.6
million tons in 2010, and 2.5 million in
2015; NO
X
caps of 1.5 in 2009 and 1.3
in 2015; and NO
X
ozone season caps of
580,000 tons in 2009 and 480,000 tons
in 2015. Emission caps are divided into
State SO
2
and NO
X
budgets. By the year
2015, the Clean Air Interstate Rule is
estimated to result in:
—$85 to $100 billion in annual health
benefits, including preventing 17,000
premature deaths, millions of lost
work and school days, and tens of
thousands of non-fatal heart attacks
and hospital admissions annually.
—Nearly $2 billion in annual visibility
benefits in southeastern national
parks, such as Great Smoky and
Shenandoah.
—Significant regional reductions in
sulfur and nitrogen deposition,
reducing the number of acidic lakes
and streams in the eastern U.S.
Over the past several years, EPA has
also issued a number of regulations
addressing emissions standards for new
cars, trucks and buses. These standards
are providing reductions in motor
vehicle emissions of volatile organic
compounds (VOCs, also referred to as
hydrocarbons), NO
X
, and direct PM
emissions (such as elemental carbon) as
older vehicles are retired and replaced.
Other existing rules are designed to
reduce emissions from several
categories of nonroad engines. The Tier
2 motor vehicle emission standards,
5
See
http://www.epa.gov/cair
.
6
See 64 FR 35714, July 1, 1999.
together with the associated
requirements to reduce sulfur in
gasoline, are estimated to provide
additional benefits nationally beginning
in 2004.
7
When the new tailpipe and
sulfur standards are fully implemented,
Americans are estimated to benefit from
the clean-air equivalent of removing 164
million cars from the road. These new
standards require passenger vehicles to
have emissions 77 to 95 percent cleaner
than those on the road today and require
fuel manufacturers to reduce the sulfur
content of gasoline by up to 90 percent.
In addition, the 2001 heavy-duty diesel
engine regulations
8
will lead to
continued emissions reductions as older
vehicles in that engine class are retired
and fleets turn over. New emission
standards began to take effect for model
year 2007 and apply to heavy-duty
highway engines and vehicles. These
standards are based on the use of high-
efficiency catalytic exhaust emission
control devices or comparably effective
advanced technologies. Because these
devices are damaged by sulfur, the level
of sulfur in highway diesel fuel was to
be reduced by 97 percent by mid-2006.
We project a 2.6 million ton reduction
of NO
X
emissions in 2030 when the
current heavy-duty vehicle fleet is
completely replaced with newer heavy-
duty vehicles that comply with these
emission standards. By 2030, we
estimate that this program will reduce
annual emissions of hydrocarbons by
115,000 tons and PM by 109,000 tons.
These emissions reductions are on par
with those that we anticipate from new
passenger vehicles and low sulfur
gasoline under the Tier 2 program.
The EPA also finalized national rules
in May 2004 to reduce significantly
PM
2.5
and NO
X
emissions from nonroad
diesel-powered equipment.
9
These
nonroad sources include construction,
agricultural, and industrial equipment,
and their emissions constitute an
important fraction of the inventory for
direct PM
2.5
emissions (such as
elemental carbon and organic carbon),
and NO
X
. The EPA estimates that
affected nonroad diesel engines
currently account for about 44 percent
of total diesel PM emissions and about
12 percent of total NO
X
emissions from
mobile sources nationwide. These
proportions are even higher in some
urban areas. The diesel emission
standards will reduce emissions from
this category by more than 90 percent,
7
See Tier II emission standards at 65 FR 6698,
February 10, 2000.
8
See heavy-duty diesel engine regulations at 66
FR 5002, January 18, 2001.
9
For more information on the proposed nonroad
diesel engine standards, see EPA’s Web site:
http://www.epa.gov/nonroad/.
and are similar to the onroad engine
requirements implemented for highway
trucks and buses. Because the emission
control devices can be damaged by
sulfur, EPA also established
requirements to reduce the allowable
level of sulfur in nonroad diesel fuel by
more than 99 percent by 2010. In 2030,
when the full inventory of older
nonroad engines has been replaced, the
nonroad diesel program will annually
prevent up to 12,000 premature deaths,
one million lost work days, 15,000 heart
attacks and 6,000 children’s asthma-
related emergency room visits.
The EPA expects the implementation
of regional and national emission
reduction programs such as CAIR and
the suite of mobile source rules
described above to provide significant
air quality improvements for PM
2.5
nonattainment areas. At the same time,
analyses for the final CAIR rule indicate
that without implementation of local
measures, a number of PM
2.5
areas are
projected to remain in nonattainment
status in the 2010–2015 timeframe.
Thus, EPA believes that local and State
emission reduction efforts will need to
play an important role in addressing the
PM
2.5
problem as well. The EPA will
work closely with States, Tribes, and
local governments to develop
appropriate in-state pollution reduction
measures to complement regional and
national strategies to meet the standards
expeditiously and in a cost-effective
manner. States will need to evaluate
technically and economically feasible
emission reduction opportunities and
determine which measures can be
reasonably implemented in the near
term. Local and regional emission
reduction efforts should proceed
concurrently and expeditiously.
The promulgation of a revised 24-
hour PM
2.5
standard effective on
December 18, 2006 has initiated another
process of State recommendations, and
the eventual designation by EPA of
areas not attaining the revised standard.
The additional designations are to be
completed within two years from the
effective date, although EPA may take
an additional year to complete the
designations if it determines it does not
have sufficient information. State plans
to attain the 24-hour standard would
then be due within three years of the
final designations. A number of areas,
including some that are already
designated as not attaining the 1997
standards, may be exceeding the revised
24-hour standard. The EPA encourages
State and local governments to be
mindful of the strengthened 24-hour
standard as they adopt emission
reduction strategies to attain the 1997
standards. Such steps may help with
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future attainment efforts, or even help
some areas avoid a nonattainment
designation for the 24-hour standard in
the first place.
The public health benefits of meeting
the PM
2.5
standards are estimated to be
significant. Even small reductions in
PM
2.5
levels may have substantial health
benefits on a population level. For
example, in a moderate-sized
metropolitan area with a design value of
15.5
µ
g/m3, efforts to improve annual
average air quality down to the level of
the standard (15.0
µ
g/m3) are estimated
to result in as many as 25–50 fewer
mortalities per year due to air pollution
exposure. In a smaller city, the same air
quality improvement from 15.5 to 15.0
µ
g/m3 still are estimated to result in a
number of avoided mortalities per year.
These estimates are based on EPA’s
standard methodology for calculating
health benefits as used in recent
rulemakings.
10
In addition, because
many different precursors contribute to
the formation of fine particles,
reductions in pollutants that contribute
to PM
2.5
also can provide concurrent
benefits in addressing a number of other
air quality problems—such as ground-
level ozone, regional haze, toxic air
pollutants, and urban visibility
impairment.
In order to assist States in developing
effective plans to address the local
component of the PM
2.5
nonattainment
problem, EPA is issuing this final fine
particle implementation rule. The EPA
is issuing this rule to implement the
1997 PM
2.5
NAAQS in accordance with
the statutory requirements of the CAA
set forth in Subpart 1 of Part D of Title
1,
i.e.
, sections 171–179B of the Act.
The EPA believes that the CAA directs
the Agency to implement new or revised
NAAQS in nonattainment areas solely
in accordance with Subpart 1, unless
another Subpart of the Act also applies
to the particular NAAQS at issue. In this
case, EPA has concluded that Congress
did not intend the Agency to implement
particulate matter NAAQS other than
those using PM
10
as the indicator in
accordance with Subpart 4 of Part D of
Title 1,
i.e.
, sections 188–190 of the
CAA. Moreover, EPA believes that
implementation of the PM
2.5
NAAQS
under the provisions of Subpart 1 is
more appropriate, given the inherent
nature of the PM
2.5
nonattainment
problem. In contrast to PM
10
, EPA
10
See: U.S. EPA 2006. Regulatory Impact
Analysis for the Particulate Matter National
Ambient Air Quality Standards. Air Benefits and
Cost Group, Office of Air Quality Planning and
Standards, Research Triangle Park, N.C. October 6,
2006. Appendix A provides an analysis of estimated
benefits and costs of attaining the 1997 PM NAAQS
standards in 2015.
anticipates that achieving the NAAQS
for PM
2.5
will generally require States to
evaluate different sources for controls,
to consider controls of one or more
precursors in addition to direct PM
emissions, and to adopt different control
strategies. As a result, EPA has
concluded that the provisions of
Subpart 1 will allow States and EPA to
tailor attainment plans so that they can
be based more specifically upon the
facts and circumstances of each
nonattainment area.
The proposed clean air fine particle
implementation rule was issued on
November 1, 2005 (70 FR 65984). About
100 comments were received from
private citizens and parties representing
industry, state and local governments,
environmental groups, and federal
agencies. Section II of this document
describes the primary elements of the
fine particle implementation program.
Each section summarizes the relevant
policies and options discussed in the
proposed rule, discusses the final policy
set forth by EPA in the final rule, and
provides responses to the major
comments received on each issue.
II. Elements of the Clean Air Fine
Particle Implementation Rule
A. Precursors and Pollutants
Contributing to Fine Particle Formation
1. Introduction
The main precursor gases associated
with fine particle formation are SO
2
,
NO
X
, volatile organic compounds
(VOC), and ammonia. This section
provides technical background on each
precursor, discusses the policy
approach for addressing each precursor
under the PM
2.5
implementation
program, and responds to key issues
raised in the public comment process. A
subsection is also included on direct
PM
2.5
emissions to address key
comments received on this issue as
well.
Gas-phase precursors SO
2
, NO
X
, VOC,
and ammonia undergo chemical
reactions in the atmosphere to form
secondary particulate matter. Formation
of secondary PM depends on numerous
factors including the concentrations of
precursors; the concentrations of other
gaseous reactive species; atmospheric
conditions including solar radiation,
temperature, and relative humidity
(RH); and the interactions of precursors
with preexisting particles and with
cloud or fog droplets. Several
atmospheric aerosol species, such as
ammonium nitrate and certain organic
compounds, are semivolatile and are
found in both gas and particle phases.
Given the complexity of PM formation
processes, new information from the
scientific community continues to
emerge to improve our understanding of
the relationship between sources of PM
precursors and secondary particle
formation.
As an initial matter, it is helpful to
clarify the terminology we use
throughout this notice to discuss
precursors. We recognize NO
X
, SO
2
,
VOCs, and ammonia as precursors of
PM
2.5
in the scientific sense because
these pollutants can contribute to the
formation of PM
2.5
in the ambient air. In
section II.K on emission inventory
issues, we make the point that because
of the complex and variable interaction
of multiple pollutants and precursors in
the formation of fine particles, it is
important for States and EPA to
continue to characterize and improve
the emissions inventories for all PM
2.5
precursors. The States and EPA need to
use the best available information
available in conducting air quality
modeling and other assessments. At the
same time, the refinement of emissions
inventories, the overall contribution of
different fine particle precursors to
PM
2.5
formation, and the efficacy of
alternative potential control measures
will vary by location. This requires that
we further consider in this action how
States should address these PM
2.5
precursors in their PM
2.5
attainment
plan programs. Thus, we require
emission inventories to include the best
available information on all pollutants
and precursors that contribute to PM
2.5
concentrations, and at same time we use
the term ‘‘PM
2.5
attainment plan
precursor’’ to describe only those
precursors that are required to be
evaluated for control strategies in a
specific PM
2.5
nonattainment area or
maintenance area plan.
In this rule, EPA has not made a
finding that all precursors should be
evaluated for possible controls in each
specific nonattainment area. The policy
approach in the rule instead requires
sulfur dioxide to be evaluated for
control measures in all areas, and
describes general presumptive policies
for NO
X
, ammonia, and VOC for all
nonattainment areas. The rule provides
a mechanism by which the State and/or
EPA can make an area-specific
demonstration to reverse the general
presumption for these three precursors.
States must also consider any relevant
information brought forward by
interested parties in the SIP planning
and development process. (See section
II.A.8 for additional discussion on these
issues.)
In the following sections, we discuss
how States must evaluate PM
2.5
precursors for nonattainment program
issues in PM
2.5
implementation plans,
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including issues such as RACT, RACM,
and reasonable further progress. This
discussion in the final rule is linked to
precursor policies for the
implementation of the new source
review program, the transportation
conformity program, the general
conformity program, and the regional
haze program. All of these programs
take effect prior to approval of SIPs for
attaining the PM
2.5
NAAQS. In the case
of NSR, the program applies on the
effective date of the nonattainment area
designation. In the case of
transportation conformity and general
conformity, the program takes effect 1
year from the effective date of
designation of the nonattainment area
(i.e., April 5, 2006 for areas designated
nonattainment effective April 5, 2005).
Thus, for each of these programs there
is an interim period between the date
the program becomes applicable to a
given nonattainment area and the date
the State receives EPA approval of its
overall PM
2.5
implementation plan.
2. Legal Authority to Regulate
Precursors
a. Background
The CAA authorizes the Agency to
regulate criteria pollutant precursors.
The term ‘‘air pollutant’’ is defined in
section 302(g) to include ‘‘any
precursors to the formation of any air
pollutant, to the extent the
Administrator has identified such
precursor or precursors for the
particular purpose for which the term
‘air pollutant’ is used.’’ The first clause
of this second sentence in section 302(g)
explicitly authorizes the Administrator
to identify and regulate precursors as air
pollutants under other parts of the CAA.
In addition, the second clause of the
sentence indicates that the
Administrator has discretion to identify
which pollutants should be classified as
precursors for particular regulatory
purposes. Thus, we do not necessarily
construe the CAA to require that EPA
identify a particular precursor as an air
pollutant for all regulatory purposes
where it can be demonstrated that
various CAA programs address different
aspects of the air pollutant problem.
Likewise, we do not interpret the CAA
to require that EPA treat all precursors
of a particular pollutant the same under
any one program when there is a basis
to distinguish between such precursors.
For example, in a rule addressing PM
2.5
precursors for purposes of the
transportation conformity program, we
chose to adopt a different approach for
one precursor based on the limited
emissions of that precursor from onroad
mobile sources and the degree to which
it contributes to PM
2.5
concentrations.
(70 FR 24280; May 6, 2005).
Other provisions of the CAA reinforce
our reading of section 302(g) that
Congress intended precursors to
NAAQS pollutants to be subject to the
air quality planning and control
requirements of the CAA, but also
recognized that there may be
circumstances where it is not
appropriate to subject precursors to
certain requirements of the CAA.
Section 182 of the CAA provides for the
regulation of NO
X
and VOCs as
precursors to ozone in ozone
nonattainment areas, but also provides
in section 182(f) that major stationary
sources of NO
X
(an ozone precursor) are
not subject to emission reductions
controls for ozone where the State
shows through modeling that NO
X
reductions do not decrease ozone.
Section 189(e) provides for the
regulation of PM
10
precursors in PM
10
nonattainment areas, but also recognizes
that there may be certain circumstances
(e.g. if precursor emission sources do
not significantly contribute to PM
10
levels) where it is not appropriate to
apply control requirements to PM
10
precursors. The legislative history of
Section 189(e) recognized the
complexity behind the science of
precursor transformation into PM
10
ambient concentrations and the need to
harmonize the regulation of PM
10
precursors with other provisions of the
CAA:
The Committee notes that some of these
precursors may well be controlled under
other provisions of the CAA. The Committee
intends that * * * the Administrator will
develop models, mechanisms, and other
methodology to assess the significance of the
PM
10
precursors in improving air quality and
reducing PM
10
. Additionally, the
Administrator should consider the impact on
ozone levels of PM
10
precursor controls. The
Committee expects the Administrator to
harmonize the PM
10
reduction objective of
this section with other applicable regulations
of this CAA regarding PM
10
precursors, such
as NO
X
. See H. Rpt. 101–490, Pt. 1, at 268
(May 17, 1990), reprinted in S. Prt. 103–38,
Vol. II, at 3292.
In summary, section 302(g) of the
CAA clearly calls for the regulation of
precursor pollutants, but the CAA also
identifies circumstances when it may
not be appropriate to regulate precursors
and gives the Administrator discretion
to determine how to address particular
precursors under various programs
required by the CAA. Due to the
complexities associated with precursor
emissions and their variability from
location to location, we believe that in
certain situations it may not be effective
or appropriate to control a certain
precursor under a particular regulatory
program or for EPA to require similar
control of a particular precursor in all
areas of the country.
b. Final Rule
The final rule maintains the same
legal basis for regulating precursors as
was described in the proposal and in the
background section above. We also
include a clarification of the term
‘‘significant contributor.’’
In the proposal, when considering the
impacts of the precursors NO
X
, VOC
and ammonia on ambient
concentrations of particulate matter, we
referred to the possibility of reversing
the presumed approach for regulating or
not regulating a precursor if it can be
shown that the precursor in question is
or is not a ‘‘significant contributor’’ to
PM
2.5
concentrations within the specific
nonattainment area. ‘‘Significant
contribution’’ in this context is a
different concept than that in Section
110(a)(2)(D). Section 110(a)(2)(D)
prohibits States from emitting air
pollutants in amounts which
significantly contribute to
nonattainment or other air quality
problems in other states. Consistent
with the discussion of sections 189(e)
and 302(g) above, we are clarifying that
the use in this implementation rule of
the term ‘‘significant contribution’’ to
the nonattainment area’s PM
2.5
concentration means that a significant
change in emissions of the precursor
from sources in the state would be
projected to provide a significant change
in PM
2.5
concentrations in the
nonattainment area. For example, if
modeling indicates that a reduction in a
state’s NO
X
emissions would reduce
ambient PM
2.5
levels in the
nonattainment area, but that a reduction
in ammonia emissions would result in
virtually no change in ambient PM
2.5
levels, this would suggest that NO
X
is a
significant contributor but that ammonia
is not. The EPA in this rule is not
establishing a quantitative test for
determining whether PM
2.5
levels in a
nonattainment area change significantly
in response to reductions in precursor
emissions in a state. However, in
considering this question, it is relevant
to consider that relatively small
reductions in PM
2.5
levels are estimated
to result in worthwhile public health
benefits.
This approach to identifying a
precursor for regulation reflects
atmospheric chemistry conditions in the
area and the magnitude of emissions of
the precursor in the area or State.
Assessments of which source categories
are more cost effective or technically
feasible to control should be part of the
later RACT and RACM assessment, to
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occur after the basic assessment of
which precursors are to be regulated is
completed.
In the proposed regulatory text, the
provisions for reversing presumptions
for NO
X
, VOC and ammonia included
consideration of whether the precursor
would significantly contribute to ‘‘other
downwind air quality concerns.’’ In the
final rule we have removed that
language to clarify that identification of
attainment plan precursors involves
evaluation of the impact on PM
2.5
levels
in a nonattainment area of precursor
emissions from sources within the
state(s) where the nonattainment area is
located. Other parts of the Act, notably
section 110(a)(2)(D) and section 126,
focus on interstate transport of
pollutants.
c. Comments and Responses
Comment:
The EPA received several
comments supporting EPA’s
interpretation of 302(g) to determine the
appropriate regulatory status of each
precursor pollutant.
Response:
The EPA agrees with the
commenters. In establishing section
302(g), Congress intended that
precursors to NAAQS pollutants be
subject to the air quality planning and
control requirements of the CAA.
However, the CAA also recognizes that
there may be circumstances where it is
not appropriate to subject precursors to
certain requirements of the CAA.
Comment:
The EPA received several
comments regarding the applicability of
section 189(e), noting that it requires
states to presumptively control sources
of PM
10
precursors except where the
EPA ‘‘determines that such sources [of
precursors] do not significantly
contribute to PM
10
levels which exceed
the standard in the area.’’ Several
commenters stated that EPA does not
have the legal authority to regulate
PM
2.5
precursors in a different manner.
Several commenters maintained that all
PM
2.5
precursors presumptively should
be subject to regulation unless
demonstrated by the State as not a
significant contributor to PM
2.5
concentrations in a specific area.
Response:
As stated above, EPA
believes that section 302(g) allows the
Administrator to presumptively not
require certain precursors to be
addressed in PM
2.5
implementation
plans generally, while allowing the
State or EPA to make a finding for a
specific area to override the general
presumption. In the following pollutant-
specific sections of this preamble, EPA
finds that at this time there is sufficient
uncertainty regarding whether certain
precursors significantly contribute to
PM
2.5
concentrations in all
nonattainment areas such that the
policy set forth in this rule does not
presumptively require certain
precursors (ammonia, VOC) to be
controlled in each area. However, the
State or EPA may reverse the
presumption and regulate a precursor if
it provides a demonstration showing
that the precursor is a significant
contributor to PM
2.5
concentrations in
the area. In addition, if in the State’s SIP
planning and adoption process a
commenter provides additional
information suggesting an alternative
policy for regulating a particular
precursor, the State will need to
respond to this information in its
rulemaking action.
3. Policy for Ammonia
[Section II.E.2 of November 1, 2005
proposed rule (70 FR 65999); sec.
51.1002 in draft and final regulatory
text.]
a. Background
Ammonia (NH
3
) is a gaseous pollutant
that is emitted by natural and
anthropogenic sources. Emissions
inventories for ammonia are considered
to be among the most uncertain of any
species related to PM. Ammonia serves
an important role in neutralizing acids
in clouds, precipitation and particles. In
particular, ammonia neutralizes sulfuric
acid and nitric acid, the two key
contributors to acid deposition (acid
rain). Deposited ammonia also can
contribute to problems of eutrophication
in water bodies, and deposition of
ammonium particles may effectively
result in acidification of soil as
ammonia is taken up by plants. The
NARSTO Fine Particle Assessment
11
indicates that reducing ammonia
emissions where sulfate concentrations
are high may reduce PM
2.5
mass
concentrations, but may also increase
the acidity of particles and
precipitation. An increase in particle
acidity is suspected to be linked with
human health effects and with an
increase in the formation of secondary
organic compounds. Based on the above
information and further insights gained
from the NARSTO Fine Particle
Assessment, it is apparent that the
formation of particles related to
ammonia emissions is a complex,
nonlinear process.
Though recent studies have improved
our understanding of the role of
ammonia in aerosol formation, ongoing
research is required to better describe
11
NARSTO (2004) (
Particulate Matter
Assessment for Policy Makers:
A NARSTO
Assessment. P. McMurry, M. Shepherd, and J.
Vickery, eds. Cambridge University Press,
Cambridge, England. ISBN 0 52 184287 5.
the relationships between ammonia
emissions, particulate matter
concentrations, and related impacts.
The control techniques for ammonia
and the analytical tools to quantify the
impacts of reducing ammonia emissions
on atmospheric aerosol formation are
both evolving. Also, area-specific data
are needed to evaluate the effectiveness
of reducing ammonia emissions on
reducing PM
2.5
concentrations in
different areas, and to determine where
ammonia decreases may increase the
acidity of particles and precipitation.
The proposal showed consideration
for the uncertainties about ammonia
emissions inventories and about the
potential efficacy of ammonia control
measures by providing for a case-by-
case approach. It was recommended that
each State should evaluate whether
reducing ammonia emissions would
lead to PM
2.5
reductions in their specific
PM
2.5
nonattainment areas. The
proposed policy did not require States
to address ammonia as a PM
2.5
attainment plan precursor, unless a
technical demonstration by the State or
EPA showed that ammonia emissions
from sources in the State significantly
contribute to PM
2.5
concentrations in a
given nonattainment area or to other
downwind air quality concerns. Where
the State or EPA has determined that
ammonia is a significant contributor to
PM
2.5
formation in a nonattainment
area, the State would be required to
evaluate control measures for ammonia
emissions in its nonattainment SIP due
in 2008, in the implementation of the
PM program, and in other associated
programs in that area.
b. Final Rule
In the final rule, ammonia is
presumed not to be a PM
2.5
attainment
plan precursor, meaning that the State is
not required to address ammonia in its
attainment plan or evaluate sources of
ammonia emissions for reduction
measures. This presumption can be
reversed based on an acceptable
technical demonstration for a particular
area by the State or EPA. If a technical
demonstration by the State or EPA
shows that ammonia emissions from
sources in the State significantly
contribute to PM
2.5
concentrations in a
given nonattainment area, the State
must then evaluate and consider control
strategies for reducing ammonia
emissions in its nonattainment SIP due
in 2008, in the implementation of the
PM
2.5
program. Technical
demonstrations on ammonia should also
consider the potential for atmospheric
and particle acidity to increase with
ammonia reductions. Further discussion
about technical demonstrations to
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support reversing a PM
2.5
precursor
presumption is included in section
II.A.8 below.
This approach was retained from the
proposal because of continued
uncertainties regarding ammonia
emission inventories and the effects of
ammonia emission reductions.
Ammonia emission inventories are
presently very uncertain in most areas,
complicating the task of assessing
potential impacts of ammonia emissions
reductions. In addition, data necessary
to understand the atmospheric
composition and balance of ammonia
and nitric acid in an area are not widely
available across PM
2.5
nonattainment
areas, making it difficult to predict the
results of potential ammonia emission
reductions. Ammonia reductions may
be effective and appropriate for
reducing PM
2.5
concentrations in
selected locations, but in other locations
such reductions may lead to minimal
reductions in PM
2.5
concentrations and
increased atmospheric acidity. Research
projects continue to expand our
collective understanding of these issues,
but at this time EPA believes this case-
by-case policy approach is appropriate.
In light of these uncertainties, we
encourage States to continue efforts to
better understand the role of ammonia
in its fine particle problem areas.
c. Comments and Responses
Comment:
One commenter stated that
scientific understanding of the
complexities of PM formation from
ammonia is limited. The commenter
claimed that the reduction of ammonia
will not reduce PM in many areas, and
speciated PM data to investigate the
potential decrease in PM from ammonia
emissions reductions is not available in
all areas.
Response:
The final rule takes these
uncertainties into consideration by
allowing ammonia to be addressed on a
case-by-case basis. For any area about
which enough information is available
to determine that ammonia emission
reductions would lead to a beneficial
reduction in PM
2.5
, the State can
develop a technical demonstration
justifying the control of ammonia. If the
State chooses to develop such a
demonstration, preferably it should be
completed as part of the SIP
development process and prior to the
adoption of control measures, in
consultation with the appropriate EPA
regional office.
Comment:
Some commenters claimed
that requiring no action on some
precursors is counter to the requirement
in sections 172(a)(2) and 188 to attain
the NAAQS as expeditiously as
practicable. They also asserted that
presuming that ammonia is not a PM
2.5
attainment plan precursor violates
302(g) by improperly delegating
authority to the States.
Response:
In many areas, reducing
ammonia emissions could have little
effect on PM
2.5
concentrations and could
lead to the potentially harmful effect of
increased atmospheric acidity. While
States are not required to take action on
ammonia sources under this policy,
States would be required to address
information on ammonia brought to
their attention during the planning and
rule adoption process. Under this
approach, States should assess whether
ammonia reductions would lead to
reduced PM
2.5
concentrations in specific
nonattainment areas. If the State decides
that ammonia reductions could yield
beneficial reductions in PM
2.5
, the State
should complete a technical
demonstration supporting a reversal of
the presumption. The EPA does not
believe that this approach improperly
delegates authority to the States. It
establishes a general presumption for all
areas through this rulemaking process,
and allows for the presumption to be
modified by the State or EPA on a case-
by-case basis. EPA still retains the
ability to make a technical
demonstration for any area if
appropriate to reverse the presumption
and require ammonia to be addressed in
its attainment plan.
Comment:
Some commenters stated
that the results of a large study on air
emissions from concentrated animal
feeding operations (CAFOs) should be
evaluated before requiring control of
ammonia in areas where agriculture is
alleged to be a major source.
Response:
The $15 million national
CAFO consent agreement study
coordinated by Purdue University will
greatly improve ammonia and VOC
emissions inventories and our
understanding of the impacts of
agricultural emissions on particle
formation. The EPA recognizes that the
agricultural emissions study is expected
to provide data for future planning
purposes, and we expect that some of
the results of the study will not be
available in time to be considered in the
development of PM
2.5
State
Implementation Plans dues in April
2008. However, if a State believes it has
sufficient technical information to
warrant regulation of ammonia
emissions in their 2008 implementation
plans, it may include in its plan a
demonstration to reverse the
presumption as well as emission
reduction measures. The EPA will
review each submittal on a case-by-case
basis.
Comment:
A presumption to not
address ammonia will impede certain
states (
i.e.
those that have provisions
requiring their regulations to be ‘‘no
stricter than Federal’’ provisions) from
regulating ammonia.
Response:
This presumptive approach
to ammonia will not restrict States from
addressing ammonia in their PM
2.5
attainment plans. If a State has
information indicating that reductions
in ammonia emissions would cause
beneficial reductions in PM
2.5
concentrations, the State can make a
technical demonstration to reverse the
presumption. In such cases, inclusion of
ammonia as a PM
2.5
attainment plan
precursor would not be considered
stricter than Federal requirements.
Under the policy in the final rule, the
Federal government or the State may
assess the impact of ammonia in a
particular area and determine whether
the presumption of insignificance is
appropriate or whether ammonia is in
fact a significant contributor to the PM
2.5
problem in the area.
4. Policy for VOC
[Section II.E.2 of November 1, 2005
proposed rule (70 FR 65999); sec.
51.1002 in draft and final regulatory
text.]
a. Background
The VOC policy in this rule addresses
volatile and semivolatile organic
compounds, generally up to 24 carbon
atoms. High molecular weight organic
compounds (typically 25 carbon atoms
or more) are emitted directly as primary
organic particles and exist primarily in
the condensed phase at ambient
temperatures. Accordingly, high
molecular weight organic compounds
are to be regulated as primary PM
2.5
emissions for the purposes of the PM
2.5
implementation program.
The organic component of ambient
particles is a complex mixture of
hundreds or even thousands of organic
compounds. These organic compounds
are either emitted directly from sources
(i.e. primary organic aerosol) or can be
formed by reactions in the ambient air
(i.e. secondary organic aerosol, or SOA).
Volatile organic compounds are key
precursors in the formation processes
for both SOA and ozone. The relative
importance of organic compounds in the
formation of secondary organic particles
varies from area to area, depending
upon local emissions sources,
atmospheric chemistry, and season of
the year.
The lightest organic molecules (i.e.,
molecules with six or fewer carbon
atoms) occur in the atmosphere mainly
as vapors and typically do not directly
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form organic particles at ambient
temperatures due to the high vapor
pressure of their products. However,
they participate in atmospheric
chemistry processes resulting in the
formation of ozone and certain free
radical compounds (such as the
hydroxyl radical [OH]) which in turn
participate in oxidation reactions to
form secondary organic aerosols,
sulfates, and nitrates. These VOCs
include all alkanes with up to six
carbon atoms (from methane to hexane
isomers), all alkenes with up to six
carbon atoms (from ethene to hexene
isomers), benzene and many low-
molecular weight carbonyls, chlorinated
compounds, and oxygenated solvents.
Intermediate weight organic
molecules (i.e., compounds with 7 to 24
carbon atoms) often exhibit a range of
volatilities and can exist in both the gas
and aerosol phase at ambient
conditions. For this reason they are also
referred to as semivolatile compounds.
Semivolatile compounds react in the
atmosphere to form secondary organic
aerosols. These chemical reactions are
accelerated in warmer temperatures,
and studies show that SOA typically
comprises a higher percentage of
carbonaceous PM in the summer as
opposed to the winter. The production
of SOA from the atmospheric oxidation
of a specific VOC depends on four
factors: Its atmospheric abundance, its
chemical reactivity, the availability of
oxidants (O
3
, OH, HNO
3
), and the
volatility of its products. In addition,
recent work suggests that the presence
of acidic aerosols may lead to an
increased rate of SOA formation.
Aromatic compounds such as toluene,
xylene, and trimethyl benzene are
considered to be the most significant
anthropogenic SOA precursors and have
been estimated to be responsible for 50
to 70 percent of total SOA in some
airsheds. Man-made sources of
aromatics gases include mobile sources,
petrochemical manufacturing and
solvents. Some of the biogenic
hydrocarbons emitted by trees are also
considered to be important precursors of
secondary organic particulate matter.
Terpenes (and b-pinene, limonene,
carene, etc.) and the sesquiterpenes are
expected to be major contributors to
SOA in areas with significant vegetation
cover, but isoprene is not. Terpenes are
very prevalent in areas with pine
forests, especially in the southeastern
U.S. The rest of the anthropogenic
hydrocarbons (higher alkanes, paraffins,
etc.) have been estimated to contribute
5–20 percent to the SOA concentration
depending on the area.
The contribution of the primary and
secondary components of organic
aerosol to the measured organic aerosol
concentrations remains a complex issue.
Most of the research performed to date
has been done in southern California,
and more recently in central California,
while fewer studies have been
completed on other parts of North
America. Many studies suggest that the
primary and secondary contributions to
total organic aerosol concentrations are
highly variable, even on short time
scales. Studies of pollution episodes
indicate that the contribution of SOA to
the organic particulate matter can vary
from 20 percent to 80 percent during the
same day.
Despite significant advances in
understanding the origins and
properties of SOA, it remains probably
the least understood component of
PM
2.5
. The reactions forming secondary
organics are complex, and the number
of intermediate and final compounds
formed is voluminous. Some of the best
efforts to unravel the chemical
composition of ambient organic aerosol
matter have been able to quantify the
concentrations of hundreds of organic
compounds representing only 10–20
percent of the total organic aerosol
mass. For this reason, SOA continues to
be a significant topic of research and
investigation.
Current scientific and technical
information clearly shows that
carbonaceous material is a significant
fraction of total PM
2.5
mass in most
areas, that certain VOC emissions are
precursors to the formation of secondary
organic aerosol, and that a considerable
fraction of the total carbonaceous
material is likely from local as opposed
to regional sources. However, while
significant progress has been made in
understanding the role of gaseous
organic material in the formation of
organic PM, this relationship remains
complex. We recognize that further
research and technical tools are needed
to better characterize emissions
inventories for specific VOC
compounds, and to determine the extent
of the contribution of specific VOC
compounds to organic PM mass.
In light of these factors, the proposed
rule did not require States to address
VOCs as PM
2.5
attainment plan
precursors and evaluate them for control
measures, unless the State or EPA
makes a finding that VOCs significantly
contribute to a PM
2.5
nonattainment
problem in the State or to other
downwind air quality concerns. Many
PM
2.5
nonattainment areas are also
nonattainment areas for the 8-hour
ozone standard; control measures for
VOCs will be implemented in some of
these areas, potentially providing a co-
benefit for PM
2.5
concentrations.
b. Final Rule
The final rule maintains the same
policy as proposed.
12
States are not
required to address VOC in PM
2.5
implementation plans and evaluate
control measures for such pollutants
unless the State or EPA makes a
technical demonstration that emissions
of VOCs from sources in the State
significantly contribute to PM
2.5
concentrations in a given nonattainment
area. Technical demonstrations are
discussed in section II.A.8 below. If a
State chooses to make a technical
demonstration, it should be developed
in advance of the attainment
demonstration.
c. Comments and Responses
Comment:
One commenter stated that
our understanding of the complexities
of PM
2.5
formation from VOCs is
limited, that speciated PM data are not
available in all areas, and that VOC
reductions will not reduce PM
2.5
in
many areas.
Response:
The EPA acknowledges the
uncertainties regarding the role of VOC
in secondary organic aerosol formation.
For this reason the final rule does not
presumptively include VOC as a
regulated pollutant for PM planning.
However, if available data demonstrates
that control of VOC would reduce PM
2.5
concentrations in an area, the State or
EPA may include VOC as an attainment
plan precursor.
Comment:
One commenter stated that
the rationale that VOC should not be
considered a PM
2.5
attainment plan
precursor because most PM areas are
also ozone areas is not appropriate
because many ozone areas will attain
soon and VOC reductions will still be
needed for PM.
Response:
The primary rationale for
not including VOC as a PM
2.5
attainment
plan precursor in every nonattainment
area is the uncertainty regarding the
contribution of anthropogenic VOCs to
the formation of the organic carbon
portion of fine particles. In certain areas,
EPA expects that VOC control measures
will have some co-benefits in the
reduction of fine particulates. However,
this reason should not be considered the
principal reason for the policy in the
final rule that VOCs presumptively
should not be considered PM
2.5
attainment plan precursors. If a State or
EPA determines that VOCs do
contribute significantly to PM
2.5
concentrations in an area, the State will
be required to evaluate control measures
for VOC as a PM
2.5
attainment plan
12
The policy is the same as proposed, with the
clarification regarding downwind areas discussed
above (Section A.2.b).
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precursor for that area. This approach
will provide for regulation of VOCs in
locations where it is most appropriate.
Comment:
One commenter suggested
that EPA wait for the results of the
pending agricultural emissions study
before requiring control of VOCs in
agricultural areas.
Response:
The $15 million national
CAFO consent agreement study
coordinated by Purdue University will
greatly improve ammonia and VOC
emissions inventories and our
understanding of the impacts of
agricultural emissions on particle
formation. The EPA recognizes that the
agricultural emissions study is expected
to provide data for future planning
purposes, and we expect that some of
the results of the study will not be
available in time to be considered in the
development of PM
2.5
State
Implementation Plans dues in April
2008. However, if a State believes it has
sufficient technical information to
warrant regulation of VOC emissions in
their 2008 implementation plans, it may
include in its plan a demonstration to
reverse the presumption as well as
emission reduction measures. The EPA
will review each submittal on a case-by-
case basis.
5. Policy for NO
X
[Section II.E.2 of November 1, 2005
proposed rule (70 FR 65999); sec.
51.1002 in draft and final regulatory
text.]
a. Background
The sources of NO
X
are numerous and
widespread. The combustion of fossil
fuel in boilers for commercial and
industrial power generation and in
mobile source engines each account for
approximately 30 percent of NO
X
emissions in PM
2.5
nonattainment areas
(based on 2001 emission inventory
information). Nitrates are formed from
the oxidation of oxides of nitrogen into
nitric acid either during the daytime
(reaction with OH) or during the night
(reactions with ozone and water). Nitric
acid continuously transfers between the
gas and the condensed phases through
condensation and evaporation processes
in the atmosphere. However, unless it
reacts with other species (such as
ammonia, sea salt, or dust) to form a
neutralized salt, it will volatilize and
not be measured using standard PM
2.5
measurement techniques. The formation
of aerosol ammonium nitrate is favored
by the availability of ammonia, low
temperatures, and high relative
humidity. Because ammonium nitrate is
semivolatile and not stable in higher
temperatures, nitrate levels are typically
lower in the summer months and higher
in the winter months. The resulting
ammonium nitrate is usually in the sub-
micrometer particle size range.
Reactions with sea salt and dust lead to
the formation of nitrates in coarse
particles. Nitric acid may be dissolved
in ambient aerosol particles.
Based on a review of speciated
monitoring data analyses, it is apparent
that nitrate concentrations vary
significantly across the country. For
example, in some southeastern
locations, annual average nitrate levels
are in the range of 6 to 8 percent of total
PM
2.5
mass, whereas nitrate comprises
40 percent or more of PM
2.5
mass in
certain California locations. Nitrate
formation is favored by the availability
of ammonia, low temperatures, and high
relative humidity. It is also dependent
upon the relative degree of nearby SO
2
emissions because ammonia reacts
preferentially with SO
2
over NO
X
. NO
X
reductions are expected to reduce PM
2.5
concentrations in most areas. However,
it has been suggested that in a limited
number of areas, NO
X
control would
result in increased PM
2.5
mass by
disrupting the ozone cycle and leading
to increased oxidation of SO
2
to form
sulfate particles, which are heavier than
nitrate particles. Because of the above
factors, the proposed rule presumed that
States must evaluate and implement
reasonable controls on sources of NO
X
in all nonattainment areas, but allowed
for the State and EPA to develop a
technical demonstration to reverse this
presumption.
b. Final Rule
The EPA is retaining the proposed
approach in the final rule.
13
Under this
policy, States are required to address
NO
X
as a PM
2.5
attainment plan
precursor and evaluate reasonable
controls for NO
X
in PM
2.5
attainment
plans, unless the State and EPA make a
finding that NO
X
emissions from
sources in the State do not significantly
contribute to PM
2.5
concentrations in the
relevant nonattainment area. This
presumptive policy is consistent with
other recent EPA regulations requiring
NO
X
reductions which will reduce fine
particle pollution, such as the Clean Air
Interstate Rule and a number of rules
targeting onroad and nonroad engine
emissions.
Technical demonstrations that would
reverse the presumption should be
developed in advance of the attainment
demonstration and are discussed in
section II.A.8 below.
13
The policy is the same as proposed, with the
clarification regarding downwind areas discussed
above (Section A.2.b).
c. Comments and Responses
Comment:
Most commenters generally
agreed with the proposed inclusion of
NO
X
as a presumptive PM
2.5
attainment
plan precursor.
Response:
The EPA agrees with these
commenters.
Comment:
Some commenters
requested guidance on what would
constitute an acceptable demonstration
to reverse the presumption that NO
X
is
a PM
2.5
attainment plan precursor.
Response:
Guidance on technical
demonstrations to reverse the
presumptive inclusion of NO
X
in all
state implementation plans is discussed
in section II.A.8 below.
Comment:
One commenter raised
concerns that the proposed policy for
NO
X
would allow a State to find NO
X
to be an insignificant contributor to an
area’s PM
2.5
nonattainment problem and
effectively keep the State from
controlling the area’s NO
X
emissions for
other purposes, such as to address
interstate transport under section 110 of
the CAA. Section 110 requires SIPs to
prohibit emissions within the State that
would contribute significantly to
another State’s nonattainment problem
or interfere with another State’s
maintenance plan.
Response:
The identification of
precursors for regulation under this rule
is for purposes of PM
2.5
nonattainment
and maintenance plans under Part D of
the CAA. The PM
2.5
implementation
rule does not prevent a State from
regulating NO
X
sources under any other
Federal or State rule, including
interstate transport rules under Section
110.
6. Policy for SO
2
[Section II.E.2 of November 1, 2005
proposed rule (70 FR 65999); sec.
51.1002 in draft and final regulatory
text.]
a. Background
Sulfur dioxide is emitted mostly from
the combustion of fossil fuels in boilers
operated by electric utilities and other
industry. Less than 20 percent of SO
2
emissions nationwide are from other
sources, mainly other industrial
processes such as oil refining and pulp
and paper production. The formation of
sulfuric acid from the oxidation of SO
2
is an important process affecting most
areas in North America. There are three
different pathways for this
transformation.
First, gaseous SO
2
can be oxidized by
the hydroxyl radical (OH) to create
sulfuric acid. This gaseous SO
2
oxidation reaction occurs slowly and
only in the daytime. Second, SO
2
can
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dissolve in cloud water (or fog or rain
water), and there it can be oxidized to
sulfuric acid by a variety of oxidants, or
through catalysis by transition metals
such as manganese or iron. If ammonia
is present and taken up by the water
droplet, then ammonium sulfate will
form as a precipitate in the water
droplet. After the cloud changes and the
droplet evaporates, the sulfuric acid or
ammonium sulfate remains in the
atmosphere as a particle. This aqueous
phase production process involving
oxidants can be very fast; in some cases
all the available SO
2
can be oxidized in
less than an hour. Third, SO
2
can be
oxidized in reactions in the particle-
bound water in the aerosol particles
themselves. This process takes place
continuously, but only produces
appreciable sulfate in alkaline (dust, sea
salt) coarse particles. Oxidation of SO
2
has also been observed on the surfaces
of black carbon and metal oxide
particles. During the last 20 years, much
progress has been made in
understanding the first two major
pathways, but some important questions
still remain about the smaller third
pathway. Models indicate that more
than half of the sulfuric acid in the
eastern United States and in the overall
atmosphere is produced in clouds.
The sulfuric acid formed from the
above pathways reacts readily with
ammonia to form ammonium sulfate,
(NH
4
)
2
SO
4
. If there is not enough
ammonia present to fully neutralize the
produced sulfuric acid (one molecule of
sulfuric acid requires two molecules of
ammonia), part of it exists as
ammonium bisulfate, NH
4
HSO
4
(one
molecule of sulfuric acid and one
molecule of ammonia) and the particles
are more acidic than ammonium sulfate.
In certain situations (in the absence of
sufficient ammonia for neutralization),
sulfate can exist in particles as sulfuric
acid, H
2
SO
4
. Sulfuric acid often exists in
the plumes of stacks where SO
2
, SO
3
,
and water vapor are in much higher
concentrations than in the ambient
atmosphere, but these concentrations
become quite small as the plume is
cooled and diluted by mixing.
Because sulfate is a significant
contributor (e.g. ranging from 9 percent
to 40 percent) to PM
2.5
concentrations in
nonattainment areas and to other air
quality problems in all regions of the
country, EPA proposed that States
would be required to address sulfur
dioxide as a PM
2.5
attainment plan
precursor in all areas.
b. Final Rule
The final rule includes the same
policy for sulfur dioxide as in the
proposal. States are required to address
sulfur dioxide as a PM
2.5
attainment
plan precursor and evaluate SO
2
for
possible control measures in all areas.
Sulfate is an important precursor to
PM
2.5
formation in all areas, and has a
strong regional impact on PM
2.5
concentrations. This policy is consistent
with past EPA regulations, such as the
CAIR, the Clean Air Visibility Rule, the
Acid Rain rules, and the Regional Haze
rule, that require SO
2
reductions to
address fine particle pollution and
related air quality problems.
Under the transportation conformity
program, sulfur dioxide is not required
to be addressed in transportation
conformity determinations
before
a SIP
is submitted unless either the state air
agency or EPA regional office makes a
finding that on-road emissions of sulfur
dioxide are significant contributors to
the area’s PM
2.5
problem. Sulfur dioxide
would be addressed
after
a PM
2.5
SIP is
submitted if the area’s SIP contains an
adequate or approved motor vehicle
emissions budget for sulfur dioxide.
EPA based this decision on the
de
minimis
level of sulfur dioxide
emissions from on-road vehicles
currently, and took into consideration
the fact that sulfur dioxide emissions
from on-road sources will decline in the
future due to the implementation of
requirements for low sulfur gasoline
(which began in 2004) and for low
sulfur diesel fuel (beginning in 2006).
For more information, see the May 6,
2005 transportation conformity rule on
PM
2.5
precursors at 70 FR 24283.
c. Comments and Responses
Comment:
Most commenters agreed
with the proposed policy for SO
2
. One
commenter stated, ‘‘* * * requiring
states to address sulfur dioxide in
attainment planning in all areas is
consistent with the science of PM
2.5
formation and essential to effective
implementation of the PM
2.5
NAAQS.’’
Another commenter concluded that
EPA’s proposal ‘‘* * * is justified based
on the fact that SO
2
has been found to
be a significant contributor to PM
2.5
nonattainment in all areas.’’
Response:
The EPA agrees with these
comments.
Comment:
Some commenters believe
States should be able to make a
demonstration that SO
2
not be
addressed as an attainment plan
precursor. The commenters claim that
the urban increment of sulfate is
generally small, and SO
2
control will
not matter in many areas. Commenters
also note that a large percentage of the
SO
2
emission inventory is being
reduced and will be reduced further
through existing programs, and that if
attainment can be demonstrated without
additional SO
2
controls, a State should
be allowed to make that demonstration
in its SIP. One commenter stated that
whether SO
2
emissions from a given
source located in a nonattainment area
in fact contribute significantly to
ambient concentrations of sulfate and
PM
2.5
in that nonattainment area likely
will depend on a range of factors,
including source type, stack height,
location, and meteorology. The
commenter asserted that sulfate forms
over significant geographic distances
from the source of the SO
2
emissions
and may not form significant
concentrations of PM
2.5
in the local
nonattainment area.
Response:
As in the proposal, the
final rule requires SO
2
to be considered
a PM
2.5
attainment plan precursor in all
cases. Sulfate is a significant fraction of
PM
2.5
mass in all nonattainment areas
currently, and although large SO
2
reductions are projected from electric
generating units with the
implementation of the CAIR program,
sulfate is still projected to be a key
contributor to PM
2.5
concentrations in
the future. SO
2
emissions also lead to
sulfate formation on both regional and
local scales. The EPA agrees that the
extent of the contribution from a
particular source in a nonattainment
area to PM
2.5
concentrations in the area
will depend on a number of factors, and
that at times the reaction of SO
2
emissions in the atmosphere to form
sulfate particles may occur less rapidly
and extend over a significant distance.
However, at other times the conversion
of SO
2
to sulfate can occur rapidly and
local impacts from a particular source
can be more significant. States are
required to develop plans to attain as
expeditiously as practicable through the
identification of technically and
economically feasible control measures
from the full range of source categories
contributing to PM
2.5
nonattainment
areas. In developing these plans, each
State will need to consider whether
controls on local SO
2
sources would be
cost-effective and would be needed to
attain expeditiously.
7. Policy for Direct PM
[Section II.E.2 of November 1, 2005
proposed rule (70 FR 65999); sec.
51.1002 in draft and final regulatory
text.]
a. Background
This section addresses inorganic and
organic forms of directly emitted PM.
Although these direct emissions are by
definition not precursors to PM
2.5
, this
section is included to provide
information on the full range of
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components that commonly make up
fine particulate matter.
The main anthropogenic sources of
inorganic (or crustal) particles are:
entrainment by vehicular traffic on
unpaved or paved roads; mechanical
disturbance of soil by highway,
commercial, and residential
construction; and agricultural field
operations (tilling, planting and
harvesting). Industrial processes such as
quarries, minerals processing, and
agricultural crop processing can also
emit crustal materials. While much of
these emissions are coarse PM, the size
distribution can have a tail of particles
smaller than PM
2.5
.
In general, coarse PM is most
important close to the source, and not
generally a significant contributor to
regional scale PM problems. Even so,
during certain high wind events, fine
crustal PM has been shown to be
transported over very long distances.
Emission estimates of mechanically
suspended crustal PM from sources
within the U.S. are often quite high.
However, this PM is often released very
close to the ground, and with the
exception of windblown dust events,
thermal or turbulent forces sufficient to
lift and transport these particles very far
from their source are not usually
present. Thus, crustal material is only a
minor part of PM
2.5
annual average
concentrations.
Primary carbonaceous particles are
largely the result of incomplete
combustion of fossil or biomass fuels.
This incomplete combustion usually
results in emissions of both black
carbon and organic carbon particles.
High molecular weight organic
molecules (i.e., molecules with 25 or
more carbon atoms) are either emitted as
solid or liquid particles, or as gases that
rapidly condense into particle form.
These heavy organic molecules
sometimes are referred to as volatile
organic compounds, but because their
characteristics are most like direct PM
emissions, they will be considered to be
primary emissions for the purposes of
this regulation. Primary organic carbon
also can be formed by condensation of
semi-volatile compounds on the surface
of other particles.
The main combustion sources
emitting carbonaceous PM
2.5
are certain
industrial processes, managed burning,
wildland fires, open burning of waste,
residential wood combustion, coal and
oil-burning boilers (utility, commercial
and industrial), and mobile sources
(both onroad and nonroad). Certain
organic particles also come from natural
sources such as decomposition or
crushing of plant detritus. Most
combustion processes emit more organic
particles than black carbon particles. A
notable exception to this is diesel
engines, which typically emit more
black carbon particles than organic
carbon. Because photochemistry is
typically reduced in the cooler winter
months for much of the country, studies
indicate that the carbon fraction of PM
mass in the winter months is likely
dominated by direct PM emissions as
opposed to secondarily formed organic
aerosol.
Particles from the earth’s crust may
contain a combination of metallic
oxides and biogenic organic matter. The
combustion of surface debris will likely
entrain some soil. Additionally,
emissions from many processes and
from the combustion of fossil fuels
contain elements that are chemically
similar to soil. Thus, a portion of the
emissions from combustion activities
may be classified as crustal in a
compositional analysis of ambient
PM
2.5
. The proposed rule required that
States address the direct emissions of
particulate matter in their PM
2.5
attainment plans. During the comment
period, EPA received several comments
regarding the definition of what should
be regulated as ‘‘direct PM
2.5
.’’
b. Final Rule
This rule defines direct PM
2.5
emissions as ‘‘air pollutant emissions of
direct fine particulate matter, including
organic carbon, elemental carbon, direct
sulfate, direct nitrate, and miscellaneous
inorganic material (i.e. crustal
material).’’ Development of attainment
plans will include direct PM
2.5
emissions and specific PM
2.5
attainment
plan precursors.
c. Comments and Responses
Comment:
A few commenters noted
that 40 CFR 51.1000 of the proposed
rule includes definitions for both
‘‘direct PM
2.5
emissions’’ and for ‘‘PM
2.5
direct emissions.’’ They recommend
including just one definition in the final
rule.
Response:
The EPA acknowledges this
oversight and has included in the final
rule a single definition for ‘‘direct PM
2.5
emissions.’’ It reads: ‘‘Direct PM
2.5
emissions means solid particles emitted
directly from an air emissions source or
activity, or gaseous emissions or liquid
droplets from an air emissions source or
activity which condense to form
particulate matter at ambient
temperatures. Direct PM
2.5
emissions
include elemental carbon, directly
emitted organic carbon, directly emitted
sulfate, directly emitted nitrate, and
other inorganic particles (including but
not limited to crustal material, metals,
and sea salt).’’
8. Optional Technical Demonstrations
for NO
X
, VOC, and Ammonia
[Section II.E.2 of November 1, 2005
proposed rule (70 FR 65999); sec.
51.1002 in draft and final regulatory
text.]
a. Background
The proposed rule required States to
evaluate and consider control strategies
for sources of SO
2
and direct PM
2.5
emissions in all nonattainment areas.
For the precursors NO
X
, VOC, and
ammonia, the proposed rule included
presumptive policies that could be
reversed with an acceptable technical
demonstration by the State or EPA. (The
policy in the proposal presumptively
required that NO
X
emissions must be
addressed in all areas, and that VOC and
ammonia emissions do not need to be
addressed in all areas.) A number of
commenters requested additional
guidance on the criteria for an
acceptable technical demonstration.
b. Final Rule
The final rule retains provisions for
the State or EPA to conduct a technical
demonstration to reverse the
presumptive inclusion of NO
X
or to
reverse the presumptive exclusions of
ammonia and VOC as PM
2.5
attainment
plan precursors. Demonstrations to
reverse the presumptions for ammonia,
VOC, or NO
X
are to be based on the
weight of evidence of available
information, and any demonstration by
the State must be approved by EPA. The
State must demonstrate that based on
the sum of available technical and
scientific information, it would be
appropriate for a nonattainment area to
reverse the presumptive approach for a
particular precursor. The demonstration
should include information from
multiple sources, including results of
speciation data analyses, air quality
modeling studies, chemical tracer
studies, emission inventories, or special
intensive measurement studies to
evaluate specific atmospheric chemistry
in an area.
Because of the variation among
nonattainment areas in terms of such
factors as local emissions sources,
growth patterns, topography, and
severity of the nonattainment problem,
EPA believes that it would not be
appropriate to define a prescriptive set
of analyses that must be included in all
PM
2.5
precursor technical
demonstrations. The key criterion is that
any technical demonstration must fairly
represent available information.
In developing the implementation
plan for a nonattainment area, the State
should use all relevant information
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available (from EPA, the State, or other
sources) to determine the scientifically
most appropriate approach to regulating
NO
X
, ammonia, and VOC emissions in
the area. As required under any State
rulemaking process, the State must
consider and provide a response in the
record to any information or evidence
brought forward by commenters during
the SIP planning, development and
review process which indicates that the
presumption for a precursor should be
reversed. In its review of the
forthcoming State implementation plan
submittal, EPA will review the State’s
proposed precursor policies in light of
all currently available information. If
information brought forward by
commenters or the State in the SIP
development process shows that the
presumption in this rule for ammonia,
VOC or NO
X
is not technically justified
for a particular nonattainment area, the
State must conduct a technical
demonstration to reverse the
presumption. In the case of ammonia or
VOC, the State then would evaluate
control measures and implement those
measures that are technically and
economically feasible and that will
contribute to expeditious attainment of
the standards.
In the section below we suggest
examples of the types of analyses that
would be appropriate to use in
developing such a demonstration. States
are encouraged to consult with EPA in
formulating appropriate technical
demonstrations.
i.
Emission Inventory Information:
An
analysis might show that a precursor
composes a significant fraction of the
emissions inventory in an area and
therefore requires greater consideration.
Example:
Several stationary sources
emitting particular VOCs known to
contribute to SOA formation make up a
significant portion of the area’s VOC
inventory. This analysis may be useful in
conjunction with other analyses included in
a weight of evidence demonstration.
ii.
Speciation Data Information:
Analysis of data from speciation
networks might lead a State to
determine the relative importance of a
precursor to seasonal or yearly average
PM concentrations. Individual
precursors require different approaches.
Collection of new data could be used to
understand the impacts of precursors in
an area.
Example:
Nitrate ion is a large portion of
winter average PM
2.5
mass. Nitrate ion is a
major portion of PM
2.5
mass on the 10 highest
PM
2.5
days in winter in the past 3 years. The
days with the highest mass concentrations
might be indicative of inversion conditions
and/or local impacts, rather than large-scale
transport processes. For these reasons, nitrate
should be addressed in the PM
2.5
attainment
plan.
Example:
Ammonium ion data combined
with total calculated nitrate data indicates
that reductions in ammonia would reduce
PM concentrations without a sharp related
increase in particle acidity. PM speciation
data shows that PM in the area is generally
within 10% of calculated neutralization. In
places for which the needed atmospheric
data are available to determine whether
increased acidity is estimated to lead to
negative environmental effects, analysis
showing that increased acidity of particles
and precipitation would likely result from
ammonia reductions would support the
presumption against ammonia regulation.
Analysis showing that ammonia reductions
would be unlikely to increase the acidity of
particles and precipitation, and that potential
reductions in ammonia would significantly
reduce PM
2.5
levels, would support a
technical demonstration to reverse the
presumption.
iii.
Modeling Information:
Results of
atmospheric modeling may help a State
characterize the impacts of potential
precursor emission reductions on PM
2.5
concentrations in an area.
Example:
Modeling of SO
2
, NO
X
, and VOC
emission reductions result in lower sulfate
and nitrate levels but not lower secondary
organic aerosol levels. This likely indicates
that VOC reductions are not as vital as
reductions of the other precursors.
Example:
Modeled reductions of NO
X
show a potential increase in sulfate formation
through disruption of the ozone cycle. SO
2
reductions may be a better choice than NO
X
reductions.
Example:
Modeled ammonia reductions
show a projected reduction in PM
2.5
concentrations in selected areas. Although
dependant on good quality inventory data,
this type of an analysis would indicate that
the area is ammonia-limited and that
ammonia reductions may be beneficial.
Example:
Modeling shows that reductions
in SO
2
in the absence of NO
X
reductions in
an area will not result in a significant PM
2.5
reduction because more nitrate particles form
when less SO
2
is available for particle
formation. However, PM
2.5
reductions are
significant when both SO
2
and NO
X
are
reduced concurrently. This analysis would
indicate that NO
X
reductions should be
included in the PM
2.5
attainment plan for the
area.
iv.
Monitoring, Data Analysis, or
Other Special Studies:
Could include
monitoring of gases and compounds not
typically monitored under the PM
2.5
speciation network, receptor modeling
analysis, or special monitoring studies.
Example:
Data from specialized monitoring
studies can provide insights about
concentrations of ammonia gas and nitric
acid in an area and whether the area is
ammonia-limited or not. Ammonia
reductions in ammonia-limited areas
typically yield reductions in PM
2.5
concentrations. Specialized monitoring and
laboratory studies can also assess the relative
concentrations of organic compounds and
provide insights into the contributions of
different anthropogenic and biogenic VOCs
to secondary organic aerosol formation.
Example:
Receptor modeling and statistical
analysis PM
2.5
speciation monitoring data
can indicate relative contributions to PM
2.5
mass from sources with different chemical
‘‘fingerprints.’’
Example:
Additional analysis of organic
compounds on filters collected through
speciation monitoring may reveal insights
about the relative degree of carbonaceous
material considered to be from fossil fuel
combustion as opposed to combustion of
‘‘modern’’ material (such as wood or
biomass).
c. Comments and Responses
Comment:
A number of commenters
requested that the final rule include
guidance on acceptable technical
demonstrations.
Response:
The above section includes
examples designed to help States
formulate appropriate demonstrations.
Prescribing specific technical indicators
to be used in all areas would ignore the
scientific uncertainty inherent in the
relationships between precursor
emissions and the responses of
atmospheric concentrations of PM
2.5
.
Therefore, States are encouraged to
review available information and
consult with EPA in formulating
technical demonstrations appropriate to
a particular area.
B. No Classification System
1. No Classification System
a. Background
Section 172 of subpart 1 contains the
general requirements for SIPs for all
nonattainment areas. Section 172(a)(1)
states that on or after the date of
designation, the Administrator may
classify an area for the purpose of
applying an attainment date or for some
other purpose. Thus, a classification
system is allowed under section 172 of
the CAA, but is not required for the
purposes of implementing a national
ambient air quality standard. The CAA
also states that EPA may consider
certain factors in making a decision
concerning classification for areas, such
as the severity of nonattainment in such
areas, and the availability and feasibility
of the pollution control measures that
may be needed to achieve attainment. In
the proposed rule, EPA provided two
implementation approaches for
classifying PM
2.5
nonattainment areas.
Under the first approach, there would
be no classification system. Under the
second approach, a two-tiered
classification system would apply, with
areas classified as either ‘‘moderate’’ or
‘‘serious’’ based on specific criteria.
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For example, the two classification
tiers could be based on the severity of
nonattainment (e.g., serious areas would
be those with a design value above a
specific threshold), or on the attainment
date for the area (e.g., serious areas
would be those with attainment dates
after April 2010). However, any
moderate area that needs an attainment
date longer than 5 years would be
reclassified as serious. This would
ensure that areas with a more persistent
PM
2.5
problem are subject to more
stringent requirements, even if they are
not one of the areas with the highest
current design values. For such areas,
the State would be required to request
reclassification for an area and ensure
that the 2008 attainment SIP submission
for the area includes all measures
needed to meet the serious area
requirements. Under the two tiered
classification approach, we proposed
that serious PM
2.5
nonattainment areas
would be required to meet the more
stringent requirements than moderate
areas that would be defined in this
rulemaking action (e.g., lower
thresholds for RACT, fixed percentage
reduction for RFP, etc.). For serious
areas, the attainment date would be as
expeditious as practicable, but no later
than 10 years after designation,
depending on the year in which the area
would be projected to attain considering
existing control requirements and the
effect of RACM, RACT and RFP.
b. Final Rule
The EPA believes that in the case of
PM
2.5
, the no-classification approach is
the most appropriate approach. An
advantage of this approach is that it
provides a relatively simple
implementation structure for State
implementation of the PM
2.5
standards,
and avoids the need to define a
classification system and determine
classifications for each area. Without
classifications, this rule still requires
that that SIPs include all reasonable
measures that contribute to achieving
attainment as expeditiously as
practicable. (Further detail is provided
in sections D. and F. below.) Because of
differences in the nature and sources of
the PM
2.5
problem in different parts of
the country, EPA did not find it
appropriate to establish a tiered
classification system with increasing
control measure requirements. The no-
classifications approach provides States
with greater flexibility to determine the
control strategies that will be most
effective and efficient in bringing
specific areas into attainment as
expeditiously as practicable. In
addition, EPA believes that States
requesting additional time to attain the
standard beyond the initial 5 year
attainment date, provided for under
Subpart I, will need to adopt additional
or more stringent measures to meet their
obligations for RACT, RACM and
attainment that is as expeditious as
practicable. We believe that this
addresses the main concerns of those
commenters who contend that a two
tiered classification system should be
implemented.
c. Comments and Responses
Comment:
The majority of the
commenters who commented on this
issue stated that they agreed with EPA’s
preferred no classification approach.
These commenters generally stated that
they believed that EPA has the authority
not to establish a classification system
for PM
2.5
nonattainment areas. Some
commenters stated that it would also be
unreasonable, at this point in the
process, for EPA to implement a
classification scheme for the PM
2.5
standard. Many commenters support the
no classification approach because it
provides for a simple implementation
structure and/or allows greater
implementation flexibility to States,
including flexibility to address specific
problems related to individual
nonattainment areas in the most cost-
effective and expeditious manner, rather
than through a one size fits all
approach. Other commenters stated that
they believe that a classification system
is not needed because nonattainment
areas in the Eastern United States are
likely to attain the standard within a
timeframe that is consistent with the
timeframe established under Subpart 1.
Response:
The EPA agrees with these
commenters.
Comment:
Several commenters
disagreed with EPA’s preferred
approach and agreed with the two tiered
classification approach featuring a
‘‘moderate’’ and a ‘‘serious’’ area
classification. These commenters also
stated that the threat of reclassification
or ‘‘bump up’’ to a higher classification
was a powerful incentive for areas to
attain as expeditiously as practicable.
Commenters also indicated that areas
needing more time to attain the standard
should be required to implement more
stringent measures or mandatory
measures.
Response:
The EPA agrees that areas
with more severe nonattainment
problems will need to implement more
stringent measures to attain. However,
EPA does not believe that a
classification system is needed to ensure
that such measures are implemented.
The EPA believes that on balance the no
classification approach is the most
appropriate classification option for the
implementation of the PM
2.5
standard
because of the difference in contributing
sources from area to area.
Comment:
Several commenters stated
that under EPA’s preferred approach,
each State would be required to submit
an attainment demonstration proposing
an attainment date that is ‘‘as
expeditious as practicable’’ for each
area. They asserted that to allow States
to propose their own attainment dates
would invite delay in the process of
cleaning up fine particle pollution.
These commenters further stated that
States would have no incentive to set an
attainment date earlier than the outer
limit set by EPA, even if it would be
practicable to attain the NAAQS sooner.
Response:
Section 172 of the CAA
requires SIPs to demonstrate attainment
as expeditiously as practicable
regardless of whether there is a
classification system, and under this
rule states must justify that their
attainment date is as expeditious as
practicable considering all reasonable
measures. As noted above, EPA believes
that States requesting additional time to
attain the standard beyond the initial 5
year attainment date will need to adopt
additional or more stringent measures to
meet their obligations for RACT and
RACM and to attain as expeditiously as
practicable. More details on the
analytical process required for an
attainment demonstration is included in
section II.F.
Comment:
Several commenters stated
that the CAA requires regulation of the
PM
2.5
standard under Subpart 4 of Part
D. These commenters state that EPA
takes the position that it must regulate
PM
2.5
under Subpart 1 of the CAA,
which applies to nonattainment areas in
general. The commenters state that
section 7513, in Subpart 4 of Part D of
the CAA, contains specific provisions
for classification of particulate matter
nonattainment areas, and that EPA must
therefore regulate PM
2.5
under Subpart
4, which requires a moderate and
serious area classification system. Other
commenters argued that implementation
of the PM
2.5
standard must proceed
under Subpart 1 of Part D of Title I of
the CAA and cannot be governed by
Subpart 4 of Part D, which addresses the
implementation of the PM
10
standard
which is a different pollutant than
PM
2.5
.
Response:
The EPA finds that the
PM
2.5
standard should be implemented
under subpart I of the CAA, which is the
general provision of the CAA related to
NAAQS implementation. Part D of Title
I of the CAA sets forth the requirements
for SIPs needed to attain the national
ambient air quality standards. Part D
also includes a general provision under
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Subpart I which applies to all NAAQS
for which a specific subpart does not
exist. Because the PM
2.5
standards were
not established until 1997, the plan
provisions found in section 172 of
subpart 1 pertaining to plans for
nonattainment areas apply. The EPA
further agrees with comments stating
that subpart 4 on its face applies only
to the PM
10
standard. In general, the
emphasis in subpart 4 on reducing PM
10
concentrations from certain sources of
direct PM
2.5
emissions can be somewhat
effective in certain PM
2.5
nonattainment
areas but not in all. Contributions to
PM
2.5
concentrations are typically from
a complex mix of sources of primary
emissions and sources of precursor
emissions which form particles through
reactions in the atmosphere. PM
2.5
also
differs from PM
10
in terms of
atmospheric dispersion characteristics,
chemical composition, and contribution
from regional transport.
2. Rural Transport Classification Option
a. Background
The 8-hour ozone implementation
program includes a ‘‘rural transport
classification’’ for subpart 1
nonattainment areas. In the proposal for
this rule we discussed whether an area
classification of this type would be
appropriate for the PM
2.5
implementation program in light of the
fact that no currently designated PM
2.5
nonattainment area met the criteria
similar to those that apply to rural
transport areas under the ozone
implementation program.
As addressed in the proposal, a PM
2.5
nonattainment area would qualify for
the ‘‘rural transport’’ classification if it
met criteria similar to those specified for
rural transport areas for the 1-hour
ozone standard under section 182(h).
Section 182(h) defines ‘‘rural transport’’
areas as those areas that do not include,
and are not adjacent to, any part of a
Metropolitan Statistical Area (MSA) or,
where one exists, a Consolidated
Metropolitan Statistical Area (CMSA).
Section 182(h) further limits the
category to those areas whose own
emissions do not make a significant
contribution to pollutant concentrations
in those areas, or in other areas.
As discussed in the preamble to the
proposed rule, potential criteria for a
State to identify an area for a rural
transport classification under the PM
2.5
program could be similar to the criteria
used in the ozone implementation
program: A State with a PM
2.5
‘‘rural
transport’’ area would need to (1)
demonstrate that the area meets the
above criteria, (2) demonstrate using
EPA approved attainment modeling that
the nonattainment problem in the area
is due to the ‘‘overwhelming transport’’
of emissions from outside the area, and
(3) demonstrate that sources of PM
2.5
and its precursor emissions within the
boundaries of the area do not contribute
significantly to PM
2.5
concentrations
that are measured in the area or in other
areas.
An area which qualifies for the ‘‘rural
transport’’ classification would only be
required to adopt local control measures
sufficient to demonstrate that the area
would attain the standard by its
attainment date ‘‘but for’’ the
overwhelming transport of emissions
emanating from upwind States. RFP
requirements under subpart 1 would
still apply to these areas. As with other
nonattainment areas, rural transport
nonattainment areas would be subject to
NSR, transportation conformity, and
general conformity requirements. In the
proposal we solicited comments on
whether it would be appropriate to
establish less burdensome NSR
requirements in the event that a
classification for rural transport areas is
adopted in the final rule. The EPA
requested comment on whether this
type of classification option is needed at
all under the PM
2.5
implementation
program.
b. Final Rule
The final rule does not include a rural
transport classification. This type of
classification was included in the CAA
for purposes of implementing the ozone
standards because of the phenomenon
of the formation of high ozone levels far
downwind in very rural locations,
including on high elevation mountain
peaks. In reviewing the currently
designated PM
2.5
nonattainment areas, it
appears that all areas but one are within
or adjacent to a metropolitan area (
i.e.
core-based statistical area or
consolidated statistical area), and thus
would not meet the criteria discussed
above. Although PM
2.5
concentrations
are greatly affected by long-range
transport of air pollution, it appears that
nonattainment areas typically are
located in urban areas and include
significant local pollutant sources.
c. Comments and Responses
Comment:
Several commenters stated
that they do not support the adoption of
a rural transport classification because it
is not needed. Commenters stated that
given the criteria for the rural transport
classification, which greatly limits its
applicability, few if any PM
2.5
nonattainment areas can qualify for the
option. One commenter stated that EPA
modeled the rural transport
classification after the ‘‘rural transport
areas’’ provision contained in subpart 2
of the CAA, which applies only to the
ozone standard. The commenter further
states that neither Subpart 1 nor 4
contain any statutory authority for such
a classification.
Response:
The EPA believes that it
has sufficient statutory authority under
the CAA to establish a rural transport
classification, but we do not believe that
such a classification is needed.
Comment:
One commenter generally
supported the rural transport concept
and the proposed associated
requirements, with the addition that
data analysis be included as appropriate
in the required technical
demonstrations in addition to modeling.
While no PM
2.5
area currently meets the
requirements for the rural transport
classification option, several
commenters recommended that it be
maintained for potential cases in which
the PM
2.5
standards are made more
stringent, or measured air quality in
areas change in such a way that areas
would qualify for the rural transport
classification at a later date.
Response:
The EPA does not agree
that a rural transport classification is
needed. The EPA will re-evaluate the
need for such a classification as
appropriate.
C. Due Dates and Basic Requirements
for Attainment Demonstrations
a. Background
Part D of Title I of the CAA sets forth
the requirements for SIPs needed to
attain the national ambient air quality
standards. Part D includes a general
subpart 1 which applies to all NAAQS
for which a specific subpart does not
exist. The 1990 CAA Amendments do
not include any subpart for PM
2.5
because the PM
2.5
standards were not
yet established. The EPA has
determined that for PM
2.5
, the
nonattainment area plan provisions
found in section 172 of subpart 1 apply.
Section 172(b) of the CAA requires
that at the time the Agency promulgates
nonattainment area designations, the
EPA must also establish a schedule for
States to submit SIPs meeting the
applicable requirements of section
172(c) and of section 110(a)(2) of the
CAA. Nonattainment area designations
were finalized in December 2004, and a
supplemental notice was issued in April
2005. Consistent with section 172(b) of
the CAA, 40 CFR 51.1002 of the
proposed rule requires the State to
submit its attainment demonstration
and SIP revision within 3 years, or by
April 2008.
Section 51.1006 of the proposed rule
addresses the situation in which an area
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is initially designated as attainment/
unclassifiable but is later designated as
nonattainment based on air quality data
after the 2001–2003 period. Under such
circumstances, the SIP submittal date
would be 3 years from the effective date
of the redesignation, and the attainment
date would be as expeditiously as
practicable but no later than 5 years
from the effective date of the
redesignation.
The section 172(c) requirements that
States are to address under section
172(c) (including RACT, RACM, RFP,
contingency measures, emission
inventory requirements, and NSR) are
discussed in later sections of this
document. Section 110(a)(2) of the CAA
requires all States to develop and
maintain a solid air quality management
infrastructure, including enforceable
emission limitations, an ambient
monitoring program, an enforcement
program, air quality modeling, and
adequate personnel, resources, and legal
authority. Section 110(a)(2)(D) also
requires State plans to prohibit
emissions from within the State which
contribute significantly to
nonattainment or maintenance areas in
any other State, or which interfere with
programs under part C to prevent
significant deterioration of air quality or
to achieve reasonable progress toward
the national visibility goal for Federal
class I areas (national parks and
wilderness areas). In order to assist
States in addressing their obligations
regarding regionally transported
pollution, EPA has finalized the CAIR to
reduce SO
2
and nitrogen oxide
emissions from large electric generating
units.
14
To date, few states have submitted a
SIP revision addressing the section
110(a)(2) requirements for the purposes
of implementing the PM
2.5
standards.
The EPA recognizes that this situation is
due in part to the fact that there were
a series of legal challenges to the PM
standards which were not resolved until
March 2002, at which time the
standards and EPA’s decision process
were upheld (see section I.B. for further
discussion of past legal challenges to the
standards). To address the States’
continuing obligation to address the
requirements of section 110(a), 40 CFR
51.1002 of the proposed rule also
required each State to address the
required elements of section 110(a)(2) of
the CAA as part of the SIP revision
adopting its attainment plan, if it has
not already done so. On March 10, 2005,
EPA entered into a consent decree with
14
More information on the Clean Air Interstate
Rule (CAIR) is available at:
http://www.epa.gov/
cair.
Environmental Defense and American
Lung Association concerning EPA’s
failure to find that States failed to
submit SIPs to address the section
110(a)(2) requirements. As a part of that
consent decree, by no later than October
8, 2008, EPA is required to publish a
notice in the
Federal Register
related to
its determinations of whether each State
has submitted SIPs for PM
2.5
that meet
the requirements as stated under section
110(a)(2) of the CAA.
b. Final Rule
The final rule maintains the
regulatory approach described above.
c. Comments and Responses
There were no comments on this
portion of the proposal.
D. Attainment Dates
1. Background on Statutory
Requirements
Establishing attainment dates. Section
172(a)(2) states that an area’s attainment
date ‘‘shall be the date by which
attainment can be achieved as
expeditiously as practicable, but no later
than 5 years from the date such area was
designated nonattainment * * *, except
that the Administrator may extend the
attainment date to the extent the
Administrator determines appropriate,
for a period no greater than 10 years
from the date of designation as
nonattainment considering the severity
of nonattainment and the availability
and feasibility of pollution control
measures.’’
Since PM
2.5
designations have an
effective date of April 5, 2005, the initial
5-year attainment date for PM
2.5
areas
would be no later than April 5, 2010.
For an area with an attainment date of
April 5, 2010, EPA would determine
whether it had attained the standard by
evaluating air quality data from the
three previous calendar years (i.e. 2007,
2008, and 2009).
For any areas that are granted the full
5 year attainment date extension under
section 172, the attainment date would
be no later than April 5, 2015. For such
areas, EPA would determine whether
they have attained the standard by
evaluating air quality data from 2012,
2013, and 2014. Section 51.1004 of the
proposed regulations addressed the
attainment date requirement. Section
51.1004(b) provided that in their
attainment demonstrations, States
would propose an attainment date
representing attainment as
expeditiously as practicable based upon
implementation of existing Federal and
State measures, and all new reasonable
local and intrastate measures. The EPA
would approve a particular attainment
date based on its review of the
attainment demonstration.
Determining Whether an Area Has
Attained.
The EPA has the
responsibility for determining whether a
nonattainment area has attained the
standard by its applicable attainment
date. Section 179(c)(1) of the Act
requires EPA to make determinations of
attainment no later than 6 months
following the attainment date for the
area. Under section 179(c)(2), EPA must
publish a notice in the
Federal Register
identifying those areas which failed to
attain by the applicable attainment date.
The statute further provides that EPA
may revise or supplement its
determination of attainment for the
affected areas based upon more
complete information or analysis
concerning the air quality for the area as
of the area’s attainment date.
Section 179(c)(1) of the Act provides
that the attainment determination for an
area is to be based upon an area’s ‘‘air
quality data as of the attainment date.’’
The EPA will make the determination of
whether an area’s air quality is meeting
the PM
2.5
NAAQS by the applicable
attainment date primarily based upon
data gathered from the air quality
monitoring sites which have been
entered into EPA’s Air Quality System
(AQS) database. No special or additional
SIP submittal will be required from the
State for this determination.
A PM
2.5
nonattainment area’s air
quality status is determined in
accordance with appendix N of 40 CFR
part 50. To show attainment of the 24-
hour and annual standards for PM
2.5
, the
most recent three consecutive years of
data prior to the area’s attainment date
must show that PM
2.5
concentrations
over a three-year period are at or below
the levels of the standards. A complete
year of air quality data, as described in
part 50, Appendix N, comprises of all 4
calendar quarters with each quarter
containing data from at least 75 percent
of the scheduled sampling days. The
annual standard for PM
2.5
is attained
when the 3-year average annual mean
concentration is less than or equal to
15.05
µ
g/m
3
. The 24-hour standard for
PM
2.5
is met when the average of 98th
percentile values for three consecutive
calendar years at each monitoring site is
less than or equal to 65.5
µ
g/m
3
.
The EPA will begin processing and
analyzing data related to the attainment
of PM
2.5
areas immediately after the
applicable attainment date for the
affected areas. Current EPA policy,
under 40 CFR part 58, sets the deadline
for submittal of air quality data into the
AQS database for no later than 90 days
after the end of the calendar year.
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While EPA may determine that an
area’s air quality data indicates that an
area may be meeting the PM
2.5
NAAQS
for a specified period of time, this does
not eliminate the State’s responsibility
under the Act to adopt and implement
an approvable SIP. If EPA determines
that an area has attained the standard as
of its attainment date, the area will
remain classified as nonattainment until
the State has requested, and EPA has
approved, redesignation to attainment
for the area.
In order for an area to be redesignated
as attainment, the State must comply
with the five requirements listed under
section 107(d)(3)(E) of the Act. This
section requires that:
—EPA has determined that the area has
met the PM
2.5
NAAQS;
—EPA has fully approved the state’s
implementation plan;
—The improvement in air quality is due
to permanent and enforceable
reductions in emissions;
—EPA has fully approved a
maintenance plan for the area;
—The State(s) containing the area have
met all applicable requirements under
section 110 and part D.
2. Establishing Attainment Dates
a. Background
The EPA proposed rule language on
attainment dates that closely tracks the
statutory language. In the preamble,
EPA noted that the attainment date that
is as expeditious as practicable should
reflect the projected impact of existing
national and State programs (e.g. partial
implementation of the CAIR rule, final
Acid Rain Program, motor vehicle tier II
standards and heavy-duty diesel engine
standards, NO
X
SIP call, State
legislation such as Clean Smokestacks
bill in North Carolina) as well as
additional reasonable measures required
for the PM
2.5
nonattainment SIP.
With respect to its authority to extend
an area’s date beyond 5 years, EPA
stated in the preamble that the State can
submit a SIP demonstrating that it is
impracticable to attain by the 5-year
attainment date: ‘‘As stated previously,
under section 172(a)(2)(A), EPA may
grant an area an extension of the initial
attainment date for a period of one to 5
years. States that request an extension of
the attainment date under this provision
of the CAA must submit a SIP by April
5, 2008 that includes, among other
things, an attainment demonstration
showing that attainment within 5 years
of the designation date is impracticable.
It must also show that the area will
attain the standard by an alternative
date that is as expeditious as
practicable, but in no case later than 10
years after the designation date for the
area (i.e. by April 5, 2015 for an area
with an effective designation date of
April 5, 2005). An appropriate extension
in some cases may be only 1 or 2
years—a 5-year extension is not
automatic upon request.
The attainment demonstration must
provide sufficient information to show
that attainment by the initial attainment
date is impracticable due the severity of
the nonattainment problem in the area,
the lack of available control measures,
and any other pertinent information
related to these statutory criteria. States
requesting an extension of the
attainment date must also demonstrate
that all local control measures that are
reasonably available and technically
feasible for the area are currently being
implemented to bring about expeditious
attainment of the standard by the
alternative attainment date for the area.
The State’s plan will need to project the
emissions reductions expected due to
Federally enforceable national
standards, State regulations, and local
measures such as RACT and RACM, and
then conduct modeling to project the
level of air quality improvement in
accordance with EPA’s modeling
guidance. The EPA will not grant an
extension of the attainment date beyond
the initial 5 years required by section
172(a)(2)(A) for an area if the State has
not considered the implementation of
all RACM and RACT local control
measures for the area (see section III.I
for a more detailed discussion of RACT
and RACM). The EPA also will examine
whether the State has adequately
considered measures to address
intrastate transport of pollution from
sources within its jurisdiction. In
attainment planning, States have the
obligation and authority to address the
transport of pollution from one area of
the State to another. Any decision made
by EPA to extend the attainment date for
an area beyond its original attainment
date will be based on facts specific to
the nonattainment area at issue and will
only be made after providing notice in
the
Federal Register
and an opportunity
for the public to comment.’’
b. Final Rule
We are adopting the approach
described above from the proposed rule.
We also wish to clarify language that
was in the preamble to the proposed
rule regarding the criteria for an
extension. The preamble stated that
attainment date extensions would be
based on the two statutory extension
criteria—‘‘the severity of nonattainment,
and the availability and feasibility of
pollution control measures,’’—as well as
‘‘other pertinent information which
shows that additional time is required
for the area to attain the standard.’’ The
CAA does not include this third clause
and the regulatory text for the final rule
does not include this third clause. The
intent of this language in the preamble
to the proposal was that States could
include ‘‘other pertinent information’’
related to the two statutory criteria.
c. Comments and Responses
Comment:
Some commenters
expressed concern that EPA’s preamble
language appeared to assert a new basis
for granting extensions not provided by
the statute. They said EPA has authority
to extend the attainment date under
Section 7502(a)(2) based solely on
consideration of two enumerated
factors: the severity of nonattainment,
and the availability and feasibility of
control measures.
Response:
The EPA agrees that
extensions must be based upon the two
factors in the statute, which are quite
broad. A clarification of the preamble
phrase cited by the commenter is
provided above. The phrase in
question—‘‘any other pertinent
information which shows that
additional time is required for the area
to attain the standard’’—refers to
information that relates to the two
statutory factors.
Comment:
One commenter stated that
an area should qualify for an extension
only if the area will implement stringent
local controls, yet still cannot
practicably attain by the five-year
deadline. The commenter stated that at
a minimum, EPA must require states to
adopt RACM for both mobile and
stationary sources before granting an
extension. Another commenter said that
given the difficulty many areas will
have in meeting the five-year deadline
for attainment of the PM
2.5
NAAQS (and
especially in light of the fact that the
deadline occurs only 2 years after states
are to submit attainment SIPs), EPA
should provide maximum flexibility in
allowing extensions to the full 10-year
period.
Response:
The EPA agrees that
extensions should be granted only if an
area cannot practicably attain within 5
years despite application of all
reasonable measures, including RACM.
Although some measures can be
implemented within a year or two,
many measures require a longer period
for installation of controls or full
program implementation. In light of the
limited time period between the SIP
submittal deadline and the 5-year date,
EPA believes that a significant number
of areas may warrant extensions ranging
from one to 5 years, with the length of
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extension depending on the factors
described above.
Comment:
One commenter advocated
that EPA include in this final rule a
determination of those areas for which
attainment within 5 years is
impracticable. Another commenter
advocated that EPA establish guidance
based on EPA national modeling
conducted last year to establish 2015 as
constituting expeditious attainment for
certain areas.
Response:
The EPA is not determining
in this rulemaking the areas that should
receive extensions or should receive the
maximum 10-year attainment date, for
several reasons. First, EPA did not
propose such an approach. Therefore,
the public has not had the opportunity
to comment on the approach or on the
technical information on which EPA
would make such judgments.
Second, EPA believes that modeling
being conducted by the states, with
updated inventories and finer grids, will
generally provide a more reliable basis
for projecting future PM
2.5
base case
levels than national modeling
conducted by EPA with older
information. State modeling of future
year PM
2.5
levels that has been
conducted to date indicates that some
areas will start closer or farther from the
standard than EPA had projected.
Third, the SIP process provides a
forum for states to identify reasonable
controls and conduct analyses to
determine the appropriate attainment
date for an area. This process provides
for input from expert stakeholders, the
general public, other states which may
share the same multi-State
nonattainment area, and EPA on
decisions regarding controls and
attainment dates. At this time, EPA does
not have the benefit of this process to
inform a judgment as to when areas can
practicably attain. States are responsible
for developing RACM demonstrations;
at this time, EPA lacks the information
to conduct a credible RACM
demonstration for all PM
2.5
nonattainment areas.
Fourth, no State commenter
advocated that EPA attempt to make
these judgments on attainment dates in
advance of the State SIP process. The
statute gives the states the lead in
developing State implementation plans.
Comment:
Another commenter
recommends that an area should receive
an attainment date extension when
collectively the following conditions
have been met:
It is proven through modeling that
the region is adversely effected by
transport of PM
2.5
emissions from up
wind sources beyond that State’s
control;
A State has submitted and
committed to implementing all Federal
PM
2.5
emission reduction requirements
in a timely manner; and,
The extension concept is approved
through the State air agency or through
the MPO Interagency Consultation
Process at the MPO level if applicable.
Response:
This commenter advocates
for attainment date extensions without
any consideration of reasonable local
measures. As stated above, EPA believes
that extensions should be granted only
if an area cannot practicably attain
within 5 years despite application of all
reasonable measures, including RACM.
Although some measures can be
implemented within a year or two,
many measures may require a longer
period for installation of controls or full
program implementation. In light of the
limited time period between the SIP
submittal deadline and the 5-year date,
EPA believes that a significant number
of areas may warrant extensions ranging
from one to 5 years, with the length of
extension depending on the factors
described above.
3. Attainment Dates: 1-Year Extensions
a. Background
Subpart 1 provides for States to
request two 1-year extensions of the
attainment date for a nonattainment area
under limited circumstances. Section
172(a)(2)(C) of the CAA provides that
EPA initially may extend an area’s
attainment date for 1 year, provided that
the State has complied with all the
requirements and commitments
pertaining to the area in the applicable
implementation plan, and provided that
the area has had no more than a
minimal number of ‘‘exceedances’’ of
the relevant standard in the preceding
year. Because the PM
2.5
standards do not
have exceedance-based forms but are
based on 3-year averaging periods, we
interpret the air quality test in 40 CFR
51.1005 to mean that the area would
need to have ‘‘clean data’’ for the third
of the 3 years that are to be evaluated
to determine attainment.
15
By this we
mean that for the third year, the air
quality for all monitors in the area as
analyzed in accordance with Appendix
N to 40 CFR part 50 each must have an
annual average of 15.0
µ
g/m
3
or less,
and a 98th percentile of 24-hour
monitoring values of 65
µ
g/m
3
or less in
order to qualify for a 1-year extension.
(Given the rounding provisions
specified in 40 CFR part 50, Appendix
N, these criteria would be satisfied if the
concentrations before final rounding are
15
See section 51.1005 of the proposed regulation.
less than an annual average of 15.05
µ
g/
m
3
and a 24-hour value of 65.5
µ
g/m
3
.)
For example, suppose an area in
violation of the annual standard has an
attainment date of April 2010, and its
annual average for 2007 was 15.8 and
for 2008 was 15.6. If the annual average
for the area in 2009 is 14.9, then the 3-
year average would be 15.4, and it
would not have attained the standard.
We interpret section 172(a)(2)(C) as
allowing the area to submit a request to
EPA for a 1-year extension of its
attainment date to 2011 (provided the
State has also complied with its
requirements and commitments) since
the 14.9 ambient air quality value in the
third year (2009) met the test of being
at or below 15.0. Section 51.1005(a) of
the proposed regulation addresses the
initial 1-year attainment date extension.
The air quality measured in 2010 in
conjunction with prior data will
determine if the area attains the
standard, qualifies for a second 1-year
extension, or does not attain the
standard. For example, if the area’s
annual average for 2010 is 14.3, then its
3-year average for 2008–2010 would be
14.9 and it would have met the annual
standard.
If the area’s annual average for 2010
is 14.9, however, then its 3-year average
for 2008–2010 would be 15.1. In this
situation the area would not have
attained the standard, but the area
would meet the air quality test for the
second of the 1-year extensions allowed
under section 172(a)(2)(C), because the
2010 annual average was at or below
15.0. Section 51.1005(b) of the proposed
rule addresses the second 1-year
attainment date extension. After
obtaining a second 1-year extension, the
State would evaluate whether the air
quality values in 2011, in conjunction
with 2009 and 2010 data, bring the area
into attainment.
Pursuant to section 172(a)(2)(C),
States must submit additional
information to EPA to demonstrate that
they have complied with applicable
requirements, commitments, and
milestones in the implementation plan.
This information is needed in order for
EPA to make a decision on whether to
grant a 1-year attainment date extension.
The EPA will not be inclined to grant
a 1-year attainment date extension to an
area unless the State can demonstrate
that it has met important requirements
contained in the area’s implementation
plan. States must demonstrate that: (1)
Control measures have been submitted
in the form of a SIP revision and
substantially implemented to satisfy the
requirements of RACT and RACM for
the area, (2) the area has made
emissions reductions progress that
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represents reasonable further progress
(RFP) toward attainment of the NAAQS,
and (3) trends related to recent air
quality data for the area indicate that the
area is in fact making progress toward
attainment of the standard. Any
decision made by EPA to extend the
attainment date for an area will be based
on facts specific to the nonattainment
area at issue, and will only be made
after providing notice in the
Federal
Register
and an opportunity for the
public to comment.
If an area fails to attain the standard
by the attainment date, EPA would
publish a finding to this effect in
accordance with section 179 of the
CAA. The area then would be required,
within 1 year of publication of this
finding, to develop a revised SIP
containing additional emission
reduction measures needed to attain the
standard as expeditiously as practicable.
b. Final Rule
The final rule retains the proposed
criteria for states to receive a 1-year
attainment date extension for a
nonattainment area.
c. Comments and Responses
Comment:
A number of commenters
supported EPA’s ability to grant a 1-year
attainment date extension if monitoring
data indicate that the PM
2.5
levels
during the most recent year were below
15.05
µ
g/m
3
.
Response:
The EPA agrees with these
comments.
Comment:
Some commenters
recommended that a 1-year extension be
provided if the trend line of the area’s
emissions levels or air quality data
projects attainment in the extension
year.
Response:
The EPA believes that
1-year extensions should be based on air
quality data, which can be assessed
quickly after the end of the year. Basing
such extensions solely on emissions
trends would be impractical due to the
longer turnaround time needed to
evaluate emissions changes affecting a
monitor.
Comment:
One commenter believes
the current requirement is overly
stringent and inconsistent with the
statute. The commenter believes that
EPA’s proposed approach incorrectly
defines the statutory language referring
to a ‘‘minimal number of exceedances’’
of the standard in the previous year as
‘‘zero’’ exceedances. Alternatively, the
commenter suggests EPA could
withdraw this provision and provide
more detailed guidance giving the
Agency and states some flexibility to
demonstrate that exceedances were
minimal in a given case since nothing
in the statute requires the rigid
definition of minimal that EPA
proposes.
Response:
The EPA believes the
policy in the final rule is a reasonable
application of the statutory language to
a standard not based on exceedances.
The EPA does not believe it would be
appropriate to provide a 1-year
extension to an area with air quality
data showing it violating the standard
over the 3 years prior to the attainment
year.
4. Achieving ‘‘Clean Data’’
a. Background
Section III.D of the preamble to the
proposed rule describes the incentives
for attaining the standards prior to April
2008, when SIP submittals are due, or
prior to an area’s approved attainment
date. Areas with design values just over
the level of the standard may be able to
achieve reductions in the local area or
in the State so that, when their effect is
considered in combination with
reductions achieved under national
programs, they may be sufficient to
attain the standards before SIPs are due
in 2008. For example, if monitoring in
a nonattainment area shows that the air
quality for 2004–2006 meets the
standards, then the area may be subject
to reduced regulatory requirements and
be redesignated as ‘‘attainment.’’
The EPA issued a ‘‘Clean Data’’ policy
memorandum in December 2004
describing possible reduced regulatory
requirements for areas that attain the
standards, but have not yet been
redesignated as attainment.
16
b. Final Rule
In the proposed rule, EPA indicated
that it had issued this ‘‘Clean Data’’
policy to apply for purposes of the PM
2.5
standards. In this action EPA is
finalizing as a rule the statutory
interpretation that is embodied in the
policy. Section 51.1004(c). The text of
the final rule encapsulates the statutory
interpretation set forth in the policy.
Determinations as to whether individual
areas have attained the PM
2.5
standard
and thus qualify for application of the
new clean data rule will be made in the
context of rulemakings for those
individual areas.
The preamble to the proposed rule
mistakenly stated that if an area
achieved ‘‘clean data,’’ it would be
‘‘relieved of the requirements to
16
Memorandum of December 14, 2004, from
Steve Page, Director, EPA Office of Air Quality
Planning and Standards to EPA Air Division
Directors, ‘‘Clean Data Policy for the Fine Particle
National Ambient Air Quality Standards.’’ This
document is available at:
http://www.epa.gov/
pmdesignations/guidance.htm.
implement the nonattainment NSR
program otherwise required for
nonattainment areas, and instead would
implement the PSD program.’’ The EPA
wishes to clarify that the Clean Data
Policy does not provide for suspension
of the requirements for NSR nor for
RACT. The provisions at issue in the
Clean Data Policy include the
requirements for an attainment
demonstration and other related
requirements, reasonable further
progress, and contingency measures.
c. Comments and Responses
Comment:
One commenter stated that
EPA has absolutely no authority to
waive NSR or any of the CAA’s other
requirements for nonattainment areas
merely because a nonattainment area
has 3 years of clean data, nor does EPA
have authority to waive mandatory
requirements of the CAA such as NSR,
RACT, and RFP merely because EPA or
the State claims they are not needed for
attainment. The commenter believes
that the only way that a nonattainment
area can cease implementing controls
and requirements mandated for such
areas is to seek and obtain redesignation
to attainment, and demonstrate in the
process that the controls and
requirements are not needed for
maintenance of standards. The CAA has
explicit procedures and prerequisites for
redesignating nonattainment areas to
attainment (CAA sections 107(d)(3)(E)
and 175A). The EPA’s ‘‘clean data’’
proposal would illegally circumvent
those requirements.
Response:
The Clean Data policy does
not waive requirements for NSR nor for
RACT. However, EPA believes that
‘‘clean data’’ policies for the ozone and
fine particle programs are based on a
reasonable interpretation of the CAA.
The Clean Data Policy is the subject of
two EPA memoranda setting forth our
interpretation of the provisions of the
Act as they apply to areas that have
attained the relevant NAAQS. The EPA
also finalized the statutory
interpretation set forth in the policy in
a final rule, 40 CFR 51.918, as part of
its Final Rule to Implement the 8-Hour
Ozone National Ambient Air Quality
Standard—Phase 2 (Phase 2 Final Rule).
See discussion in the preamble to the
rule at 70 FR 71645–71646 (November
29, 2005). The legal rationale for the
Clean Data policy is explained in our
Phase 2 Final Rule, in our December 14,
2004 memorandum from Stephen D.
Page entitled ‘‘Clean Data Policy for the
Fine Particle National Ambient Air
Quality Standards’’ (Page Memo), and in
our May 10, 1995 memorandum from
John S. Seitz, entitled ‘‘Reasonable
Further Progress, Attainment
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Demonstration, and Related
Requirements for Ozone Nonattainment
Areas Meeting the Ozone National
Ambient Air Quality Standard’’ (Seitz
memo). We adopt and reiterate those
explications here.
The EPA has also explained its
rationale for applying the Clean Data
policy in rulemaking actions associated
with nonattainment areas for the PM
10
and 1-hour ozone standards. For
rulemaking actions applying the Clean
Data policy to the PM
10
standards, see
71 FR 27440 (May 11, 2006) (Weirton,
WVA), 71 FR 13021 (March 14, 2006)
(Yuma, AZ), 71 FR 6352 (February 8,
2006) (Ajo, AZ). For a discussion of the
legal rationale supporting rulemaking
actions applying the Clean Data policy
to the 1-hour ozone standards, see, for
example, 67 FR 49600 (July 31, 2002);
65 FR 37879 (June 19, 2000) Cincinnati-
Hamilton, Ohio-Kentucky); 61 FR 20458
(May 7, 1996) (Cleveland Akron-Lorain,
Ohio); 66 FR 53094 (October 19, 2001)
(Pittsburgh-Beaver Valley,
Pennsylvania); 61 FR 31832 (June 21,
1996 (Grand Rapids, Michigan); 60 FR
36723 (July 18, 1995) (Salt Lake and
Davis Counties, Utah); 68 FR 25418
(May 12, 2003) (St Louis, Missouri); 69
FR 21717 (April 22, 2004) (San
Francisco Bay Area).
The EPA has further elaborated on its
legal rationale for the Clean Data Policy
in briefs filed in the 10th, 7th, and 9th
Circuits, and hereby incorporates those
briefs insofar as relevant here. See
Sierra
Club
v.
EPA,
No. 95–9541 (10th Cir.),
Sierra Club
v.
EPA,
No. 03–2839, 03–
3329 (7th Cir.),
Our Children’s Earth
Foundation
v.
EPA,
No. 04–73032 (9th
Cir.). As stated in the policy, the
attainment demonstration, RFP
requirements, and contingency measure
requirement are designed to bring an
area into attainment. Once this goal has
been achieved, it is appropriate to
suspend the obligation that States
submit plans to meet these goals, so
long as the area continues to attain the
relevant standard. The Tenth, Seventh
and Ninth Circuits have all upheld EPA
rulemakings applying the Clean Data
Policy. See
Sierra Club
v.
EPA,
99 F. 3d
1551 (10th Cir. 1996);
Sierra Club
v.
EPA,
375 F. 3d 537 (7th Cir. 2004);
Our
Children’s Earth Foundation
v.
EPA,
No.
04–73032 (9th Cir. June 28, 2005
(Memorandum Opinion).
The EPA has explained in its
memoranda on the Clean Data Policy for
PM
2.5
and for ozone that it is reasonable
to interpret the provisions regarding
RFP and attainment demonstrations,
along with certain other related
provisions, as not requiring further
submissions to achieve attainment for so
long as the area is in fact attaining the
standard. Under the policy, EPA is not
granting an exemption from any
applicable requirement under Part D.
Rather, EPA has interpreted these
requirements as not applying for so long
as the area remains in attainment with
the standard. This is not a waiver of
requirements that by their terms apply;
it is a determination that certain
requirements are written so as to be
operative only if the area is not attaining
the standard.
CAA section 172(c)(2) provides that
SIP provisions in nonattainment areas
must require ‘‘reasonable further
progress.’’ The term ‘‘reasonable further
progress’’ is defined in section 171(1) as
‘‘such annual incremental reductions in
emissions of the relevant air pollutant as
are required by this part or may
reasonably be required by the
Administrator for the purpose of
ensuring attainment of the applicable
NAAQS by the applicable date.’’ Thus,
by definition, the ‘‘reasonable further
progress’’ provision requires only such
reductions in emissions as are necessary
to attain the NAAQS. If an area has
attained the NAAQS, the purpose of the
RFP requirement will have been
fulfilled, and since the area has already
attained, showing that the State will
make RFP towards attainment will
‘‘have no meaning at that point.’’ The
EPA’s General Preamble for the
Implementation of Title I of the Clean
Air Act Amendments of 1990 (General
Preamble) 57 FR 13498, 13564 (April 16,
1992).
CAA section 172(c)(1), the
requirement for an attainment
demonstration, provides in relevant part
that SIPs ‘‘shall provide for attainment
of the [NAAQS].’’ The EPA has
interpreted this requirement as not
applying to areas that have reached
attainment. If an area has attained the
standard, there is no need to submit a
plan demonstrating how the area will
reach attainment. In the General
Preamble (57 FR 13564), EPA stated that
no other measures to provide for
attainment would be needed by areas
seeking redesignation to attainment
since ‘‘attainment will have been
reached.’’ See also Memorandum from
John Calcagni, ‘‘Procedures for
Processing Requests to Redesignate
Areas to Attainment,’’ September 4,
1992, at page 6.
CAA section 172(c)(9) provides that
SIPs in nonattainment areas ‘‘[S]hall
provide for the implementation of
specific measures to be undertaken if
the area fails to make reasonable further
progress, or to attain the [NAAQS] by
the attainment date applicable under
this part. Such measures shall be
included in the plan revision as
contingency measures to take effect in
any such case without further action by
the State or [EPA].’’
This contingency measure
requirement is inextricably tied to the
reasonable further progress and
attainment demonstration requirements.
Contingency measures are implemented
if reasonable further progress targets are
not achieved, or if attainment is not
realized by the attainment date. Where
an area has already achieved attainment
by the attainment date, it has no need
to rely on contingency measures to
come into attainment or to make further
progress to attainment. As EPA stated in
the General Preamble:
‘‘The section 172(c)(9) requirements for
contingency measures are directed at
ensuring RFP and attainment by the
applicable date.’’ 57 FR 13564. Thus these
requirements no longer apply when an area
has attained the standard.
It is important to note that should an
area attain the PM
2.5
standards based on
three years of data, its obligation to
submit an attainment demonstration is
not waived but is only suspended. If the
area then has air quality concentrations
in the following year such that the area
exceeds the standard for years 2 through
4, then the area’s obligation to submit an
attainment demonstration is back in
effect.
The determination of attainment
contemplated by the Clean Data Policy
does not purport to be a redesignation,
and thus the requirements for
redesignation under section 107(d) are
not applicable. Nor does the Clean Data
Policy avoid or illegally circumvent the
redesignation requirements of section
107 of the CAA. All of the requirements
for redesignation remain in effect and
must be satisfied for an area to be
redesignated.
Sierra Club
v.
EPA
, 99
F.3d at 1557–1558. The Clean Data
Policy is simply an interpretation of
certain provisions of the CAA, whose
express purpose is to achieve attainment
of the standard, as not requiring SIP
revisions to be made by the State for so
long as the area continues to attain the
standard. The policy does not purport to
exempt areas from requirements that are
inapplicable only if an area is
redesignated to attainment. It interprets
certain provisions which are written in
such a way as to impose requirements
only upon areas that are not attaining
the NAAQS, regardless of whether they
have been redesignated to attainment.
The EPA has not provided for any
waiver from statutory requirements that
was not provided by Congress. The area
at issue remains designated
nonattainment, and is subject to the risk
that if a violation occurs it will have to
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adopt and implement reasonable further
progress requirements, contingency
measures, and an attainment
demonstration, unless it is redesignated
to attainment. In order to be
redesignated to attainment, however,
the area will have to satisfy all of the
requirements of section 107(d)(3)(E),
including the requirement for a long-
term maintenance plan.
While a determination of attainment
is not equivalent to a redesignation to
attainment, nothing in the Act compels
EPA to wait until an area meets all the
requirements for redesignation before
EPA makes a determination that the area
is in attainment with the standard,
thereby suspending the requirements for
certain provisions related to attainment.
Indeed, section 179(c) of the Act
requires EPA to make an attainment
determination within six months after
an area’s applicable attainment date
whether or not the EPA has made a
finding with respect to redesignation.
The EPA’s interpretation of the Act’s
provisions not to require, once
attainment has been reached, certain
plan submissions whose purpose is to
assure attainment, is not at odds with
the requirements for redesignation. Nor
does EPA’s construction of the statute
adversely impact planning for
maintenance. An area that is monitoring
attainment, but is still designated as a
nonattainment area, retains strong
incentives to seek redesignation to
attainment, and remains subject to the
requirement to demonstrate
maintenance in order to be
redesignated. For a detailed discussion
of the relationship of redesignation
requirements and attainment
determinations, see the discussions in
the EPA briefs in
Our Children’s Earth
Foundation
v.
EPA
, supra at pp. 43–60.,
Sierra Club
v.
EPA
No. 95–9541 (10th
Cir.) at 29–43, and
Sierra Club
v.
EPA
Nos. 03–2839, 03–3329 (7th Cir.) at 33–
44 which are contained in the docket for
this rulemaking.
Comment:
A commenter noted that
EPA’s proposal suggested that areas
attaining the standard would be subject
to reduced regulatory requirements. The
commenter believed that EPA’s
interpretation should be codified in
regulatory form, in order to assure that
areas legally meeting the current PM
2.5
standard and those requesting
redesignation be enabled to be
redesignated and to benefit from the
interpretation through regulation, rather
than by guidance or policy.
Response:
The EPA has adopted the
commenter’s suggested approach of
codifying its Clean Data Policy
interpretation for PM
2.5
in regulatory
form. Section 51.1004(c). As it did for
ozone in its Phase II Ozone
Implementation Rule, EPA is including
in this rulemaking a regulation that
encapsulates the statutory interpretation
that is embodied in its Clean Data Policy
for PM
2.5
, set forth above. As noted in
the response to comment above,
determinations as to whether individual
areas have attained the PM
2.5
standard
and thus qualify for application of the
rule will be made in the context of
rulemakings for those individual areas.
The EPA believes, however, that
encapsulating its interpretation in
regulatory form will lend clarity and
consistency to the process of applying
its interpretation.
E. Modeling and Attainment
Demonstrations
1. Background
[Section III.F.1 of November 1, 2005
proposed rule (70 FR 66007); sec
51.1007 in draft and final regulatory
text]
As noted in the proposal, Section
172(c) requires States with
nonattainment areas to submit an
attainment demonstration. An
attainment demonstration consists of:
(1) Technical analyses that locate,
identify, and quantify sources of
emissions that are contributing to
violations of the PM
2.5
NAAQS; (2)
analyses of future year emissions
reductions and air quality improvement
resulting from already-adopted national
and local programs, and from potential
new local measures to meet the RACT,
RACM, and RFP requirements in the
area; (3) adopted emission reduction
measures with schedules for
implementation; and (4) contingency
measures required under section
172(c)(9) of the CAA.
a. Final Rule
The requirements from the proposal
are unchanged. Each State with a
nonattainment area will be required to
submit a SIP with an attainment
demonstration that includes analyses
supporting the State’s proposed
attainment date. States must show that
the area will attain the standards as
expeditiously as practicable and it must
include an analysis of whether
implementation of reasonably available
measures will advance the attainment
date.
2. Areas That Need To Conduct
Modeling
[Section III.F.2 of November 1, 2005
proposed rule (70 FR 66007)]
a. Background
All nonattainment areas need to
submit an attainment demonstration,
but in some cases, States may not need
new, local-scale modeling analyses. In
the proposed rule, EPA proposed that
States may use in a PM
2.5
attainment
demonstration certain local, regional
and/or national modeling analyses that
have been developed to support Federal
or local emission reduction programs,
provided the modeling meets the
attainment modeling criteria set forth in
EPA’s modeling guidance. The proposal
also stated that nonattainment areas for
which local, regional, or national scale
modeling demonstrates the area will not
attain the standard within 5 years of
designation would be required to submit
an attainment demonstration SIP that
includes new modeling showing
attainment of the standards as
expeditiously as practicable.
b. Final Rule
In the final rule, EPA is reaffirming
the potential use of national and/or
regional modeling as part of an
attainment demonstration. We are also
clarifying the types of modeling
analyses that may be useful as a
‘‘primary’’ modeling analysis and as a
‘‘supplemental’’ analysis. The proposal
suggested that it may be appropriate, in
certain circumstances, for a State to
submit regional or national modeling as
the sole (primary) modeling analysis in
its attainment demonstration. This
implies that the State would not need to
conduct local modeling analyses. We
wish to further define the differences
between ‘‘national’’, ‘‘regional’’, and
‘‘local’’ modeling analyses. In this
context, national analyses are generally
those conducted by EPA in support of
national or regional rules. Regional and
local modeling analyses are generally
those conducted by the RPOs and/or
States for the purpose of developing
State Implementation Plans (SIPs). EPA
has conducted national scale modeling
for a variety of rules and analyses.
Additionally, the RPOs and many States
are conducting regional and/or local
scale modeling of PM
2.5
and regional
haze across the country. The national
scale of the EPA modeling analyses
requires basic assumptions concerning
local model inputs. Compared to
regional or local modeling done by the
States and/or RPOs, EPA modeling may,
in some cases, use coarser grid
resolution, use inventories that are not
as refined, and model performance may
be highly variable from area to area. For
these reasons, national scale modeling
may not always be appropriate for local
area attainment demonstrations.
Therefore, we believe that regional or
local modeling conducted by the States
or RPOs is best suited as the primary
modeling analysis for a modeled
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attainment demonstration. The local
modeling is more likely to meet the
recommendations contained in EPA’s
modeling guidance. However, some
areas having design values close to the
standard may be projected to come into
attainment within five years based on
modeling analyses of national and
regional emission control measures (e.g.
CAIR) that are scheduled to occur
through 2009. Regional scale modeling
for national rules such as the Tier II
motor vehicle standards, the Heavy-duty
Engine standards, the Nonroad Engine
standards, and CAIR indicate major
reductions in PM
2.5
by 2010. A portion
of these benefits will occur in the 2006–
2009 PM
2.5
attainment timeframe.
Experience with past ozone
attainment demonstrations has shown
that the process of performing detailed
photochemical grid modeling to develop
an attainment demonstration can be
very resource intensive for States. The
EPA believes that it would be
appropriate for States to leverage
resources by collaborating on modeling
analyses to support SIP submittals, or by
making use of recent modeling analyses
that are completed prior to the SIP
submittal date. For this reason, EPA
recognizes that States may use in a
PM
2.5
attainment demonstration certain
local, regional and/or national modeling
analyses that have been developed to
support Federal or local emission
reduction programs, provided the
modeling meets the attainment
modeling criteria set forth in EPA’s
modeling guidance (described below).
As with all SIPs under subpart 1, the
State must demonstrate that the area
will attain the PM
2.5
standards as
expeditiously as practicable. The
judgment of whether the modeling is
appropriate for an area should be made
by the State(s) and their respective EPA
regional office on a case-by-case basis.
c. Comments and Responses
Comment:
There were many
commenters that agreed that States
should be able to use EPA modeling or
other national or regional modeling as a
modeled attainment demonstration. One
commenter recommended that the final
rule require States to show that the
existing modeling incorporates realistic
assumptions, accurately reflects local
emissions and trends, and provides
adequate model performance for the
local nonattainment area.
Response:
We agree that national and
regional modeling may be used as part
of an attainment demonstration as long
as it is shown to be applicable to the
local area. This is consistent with the
proposal where we said that existing
modeling should ‘‘meet the attainment
modeling criteria set forth in EPA’s
modeling guidance.’’ Part of the analysis
to determine if existing modeling meets
the criteria in the modeling guidance is
to assess whether the modeling
incorporates realistic assumptions,
accurately reflects local emissions and
trends, and provides adequate model
performance for the local nonattainment
area.
Comment:
Some commenters thought
States should be able to use EPA
modeling in the absence of an analysis
of the applicability of the modeling for
a local nonattainment area. One
commenter said that EPA should
determine that States should not have to
do any additional modeling analyses if
the CAIR modeling showed they were
expected to attain the NAAQS by 2010.
Response:
While we acknowledge
there may be some circumstances in
which national or regional modeling
would be appropriate to use without
local modeling and allow for such use,
we disagree that national modeling
should be used in support of an
attainment demonstration without
further analysis of the modeling
assumptions for a particular area.
National scale modeling may not always
be appropriate for local areas. Most
often, national scale EPA modeling is
best suited for use as a supplemental
analysis or as part of a ‘‘weight of
evidence’’ demonstration. The modeling
guidance recommends supplemental
analyses for all attainment
demonstrations. The guidance
specifically recommends the
examination of other modeling studies
as a supplemental analysis. The EPA
modeling as well as other ‘‘non-local’’
modeling can be used for this purpose.
The ‘‘weight’’ of this alternative
modeling in an attainment
demonstration should be guided by how
well the modeling system is suited for
the local nonattainment area. States
should consult with their EPA regional
offices for further guidance and
recommendations. As such, we do not
believe it to be appropriate to determine
a priori that CAIR or any other modeling
analyses are appropriate to use in a local
attainment demonstration for any or all
nonattainment areas.
Comment:
Several commenters
believe that States should be able to use
existing EPA modeling (such as CAIR),
as the basis for an extension of the area’s
attainment date, if it shows that the
nonattainment area may not be able to
attain the NAAQS by 2010. They believe
that the State should not have to do
additional modeling to show that they
need an attainment date extension.
Response:
We disagree with this
comment. The CAIR modeling included
national controls that are expected to be
in place by 2010 (including the CAIR
rule itself), as well as existing state and
local controls reflected in the inventory
used in the CAIR analysis. It did not
include any additional local controls
that could be implemented under RACT
and RACM requirements for the 1997
standards that may bring the area into
attainment sooner. Nonattainment areas
are required to attain the NAAQS as
expeditiously as practicable. Therefore,
updated modeling of existing controls as
well as additional local controls is
needed before an attainment date
extension can be granted. Additional
information on attainment dates and
extensions is contained in the preamble
to the final rule, section II.D., and
additional information on RACT and
RACM requirements is contained in
section II.F.
Comment:
Several commenters noted
an apparent inconsistency in the
language concerning who would be
required to perform ‘‘new’’ local-scale
modeling. First, there are potentially
conflicting statements in the proposal
when EPA states that areas with an
attainment date of 2010 will need to
conduct local-scale modeling to project
the estimated level of air quality
improvement in accordance with EPA’s
modeling guidance. This conflicts with
the proposed ability for States to use
existing national or regional modeling
as their modeled attainment
demonstration. Second, a portion of a
sentence was removed from the
Federal
Register
version of the notice which
differs from the pre-
Federal Register
version. The published version implies
that all nonattainment areas would be
required to submit new modeling.
Response:
We agree that there are
inconsistencies in the proposal
preamble text. To clarify, new local-
scale modeling is required for areas that
are not expected to come into
attainment by 2010. For other areas,
there may be national or regional
modeling which may be applicable to
the area which shows they are likely to
come into attainment. As noted earlier,
national scale modeling is best suited
for use as a supplemental analysis, but
in some cases may be acceptable
evidence that an area will attain by
2010.
Additionally, the preamble language
in the
Federal Register
contained an
error. A portion of a sentence was
mistakenly removed, which led to some
confusion. The language in the FR
notice (FR page 66008) stated
‘‘Nonattainment areas would be
required to submit an attainment
demonstration SIP that includes new
modeling showing attainment of the
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standards as expeditiously as
practicable. The new modeling will
need to include additional emissions
controls or measures in order to
demonstrate attainment.’’ The language
should have read, ‘‘Nonattainment areas
for which local, regional, or national
scale modeling demonstrates the area
will not be in attainment of the NAAQS
within 5 years of designation
would be
required to submit an attainment
demonstration SIP that includes new
modeling showing attainment of the
standards as expeditiously as
practicable. The new modeling will
need to include additional emissions
controls or measures in order to
demonstrate attainment.’’ This should
clarify that States that cannot show
attainment within 5 years will need to
develop new modeling analyses which
contain additional control strategies
which show how and when they expect
to attain the PM
2.5
NAAQS.
Comment:
One commenter
maintained that relying on large-scale
regional modeling alone may allow for
PM
2.5
hot spots (i.e. small unmonitored
areas projected to exceed the standard)
to exist past the attainment date.
Response:
We agree that
nonattainment areas with potential
hotspot issues (relatively high
concentrations and/or gradients of
primary PM
2.5
) should not rely
exclusively on regional modeling. The
EPA’s attainment demonstration
modeling guidance attempts to address
several aspects of hotspot issues in both
monitored and unmonitored areas
17
.
The modeled attainment tests contained
in EPA’s modeling guidance are
primarily monitor based tests. Ambient
data is combined with the model
predicted relative change in PM
components to determine if attainment
of the standards is likely in the future.
There are several aspects of the
attainment test. In most cases, States
will run a photochemical grid model to
determine the future year predicted
PM
2.5
concentrations at monitors. The
modeling guidance generally
recommends that for urban scale PM
2.5
modeling, the State performs modeling
analyses at 12 kilometer grid resolution
or finer. There is an additional
component to the attainment test for
areas that have measured relatively high
concentrations and/or gradients of
primary PM
2.5
at monitors. In these
cases, we recommend running a
Gaussian dispersion model for potential
primary PM sources, to determine the
17
The recommendations contained in the
modeled attainment demonstration guidance are
separate from the Agency’s future hot-spot
modeling guidance for transportation conformity
purposes.
local impact of changes in primary PM
emissions (from the modeled sources)
on predicted concentrations at the
monitor(s).
In addition, we describe an
‘‘unmonitored area analysis’’ which
uses interpolated ambient data
combined with gridded model outputs
to examine whether potential violations
of the NAAQS may occur in
unmonitored areas. If potential
violations are indicated, we recommend
further analysis of the problem through
additional local modeling. Options for
State action to address such a situation
could include imposition of reasonably
available control technology to reduce
emissions, or the deployment of an air
quality monitor to further characterize
the problem.
We believe that the combination of
these model-based tests will adequately
determine whether attainment of the
standards is likely by the attainment
date. We also believe that these tests
address the issue of hotspots by
recommending a combination of
photochemical modeling, dispersion
modeling of local sources, and
additional monitoring and/or emissions
controls.
3. Modeling Guidance
[Section III.F.3 of November 1, 2005
proposed rule (70 FR 66008)]
a. Background
Section 110(a)(2)(K)(i) states that SIPs
must contain air quality modeling as
prescribed by the Administrator for the
purpose of predicting the effect of
emissions on ambient air quality. The
procedures for modeling PM
2.5
as part of
an attainment SIP are contained in
EPA’s ‘‘Guidance for Demonstrating
Attainment of Air Quality Goals for
PM
2.5
and Regional Haze.’’ The proposal
summarized several of the chapters in a
draft version of the modeling guidance.
b. Final Rule
A draft of the PM
2.5
attainment
demonstration and regional haze
modeling guidance has now been
revised (September 2006) and is
available at
http://www.epa.gov/ttn/
scram/guidance
_
sip.htm.
The draft
PM
2.5
attainment demonstration and
regional haze guidance has been
incorporated into the ozone modeling
guidance and is now called ‘‘Guidance
on the Use of Models and Other
Analyses for Demonstrating Attainment
of Air Quality Goals for the 8-Hour
Ozone and PM
2.5
NAAQS and Regional
Haze’’. The final version of the
modeling guidance will be available at
the same location in the near future.
The revised draft PM
2.5
modeling
guidance document is very similar to
the previous draft version, although
there were several changes and updates.
Among them are new methods in
treating PM
2.5
species components as
part of the PM
2.5
attainment test; new
methods for determining potential
future year violations in unmonitored
areas; new procedures for handling
potential PM
2.5
‘‘hotspots’’; and an
increased reliance on supplemental
analyses, including ‘‘weight of
evidence’’ analyses. The EPA notes that
the PM
2.5
attainment demonstration
modeling guidance that we have
released is separate from the Agency’s
future hot-spot modeling guidance for
transportation conformity purposes.
18
The modeling guidance describes how
to estimate whether a control strategy to
reduce emissions of particulate matter
and its precursors will lead to
attainment of the annual and 24-hour
PM
2.5
NAAQS. Part I of the guidance
describes a ‘‘modeled attainment test’’
for the annual and 24-hour PM
2.5
NAAQS. Both tests are similar. The
output of each is an estimated future
design value consistent with the
respective forms of the NAAQS. If the
future design value does not exceed the
concentration of PM
2.5
specified in the
NAAQS, then the primary modeled test
is passed. The modeled attainment test
applies to locations with monitored
data.
A separate test is recommended to
examine projected future year PM
2.5
concentrations in unmonitored
locations.
19
Interpolated PM
2.5
ambient
data, combined with modeling data, is
used to predict PM
2.5
concentrations in
unmonitored areas. The goal of this
analysis is to identify areas without
monitors that may be violating the PM
2.5
NAAQS, often due to high levels of
primary PM
2.5
(both now and in the
future). The details of the analysis are
contained in the final modeling
guidance.
The guidance also discusses modeling
PM
2.5
at monitors where high
concentrations of primary PM
2.5
are
measured. In these cases, it may be
beneficial to model the primary
component of the PM
2.5
with a Gaussian
dispersion model. Dispersion models
are better able to capture the influence
18
In the March 10, 2006, final transportation
conformity rule (71 FR 12468), EPA committed to
develop PM
2.5
and PM
10
quantitative hot-spot
modeling guidance for transportation conformity
determinations for highway and transit projects of
local air quality concern.
19
Application of the unmonitored area analysis is
limited to locations which are appropriate to allow
the comparison of predicted PM
2.5
concentrations to
the NAAQS, based on PM
2.5
monitor siting
requirements and recommendations.
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of primary PM sources where large
concentration gradients may exist. Grid
models spread out the PM emissions to
the size of the grid (typically 4 or 12
km). This makes it difficult to judge the
benefits of control strategies that may
affect primary PM sources. The final
modeling guidance recommends
procedures for applying dispersion
models in these situations.
The guidance also recommends the
submittal of supplemental analyses as
part of all attainment demonstrations.
Supplemental analyses are modeling,
emissions, and/or ambient data analyses
that are submitted as part of a SIP, in
addition to the primary modeled
attainment test. The evaluation of
supplemental analyses when the
predicted concentrations in the primary
attainment test are close to the NAAQS
(slightly above or slightly below) is
called a weight-of-evidence (WOE)
analysis. This is simply a collection of
evidence that aims to show that
attainment of the standard is likely. The
final version of the modeling guidance
puts more emphasis on the submittal of
supplemental analyses than in previous
versions.
Part II of the guidance describes how
to apply air quality models to generate
results needed by the modeled tests for
attainment. This includes developing a
conceptual description of the problem
to be addressed; developing a modeling/
analysis protocol; selecting an
appropriate model to support the
demonstration; selecting appropriate
meteorological episodes or time periods
to model; choosing an appropriate area
to model with appropriate horizontal/
vertical resolution; generating
meteorological and air quality inputs to
the air quality model; generating
emissions inputs to the air quality
model; evaluating performance of the air
quality model; and performing
diagnostic tests. After these steps are
completed, the model is used to
simulate the effects of candidate control
strategies.
Comment:
Several commenters were
supportive of the weight of evidence
concept. They said that PM
2.5
modeling
is inherently more uncertain than
previous ozone modeling and the
modeling guidance should reflect that.
One commenter noted that weight of
evidence demonstrations should be
‘‘unbiased’’, meaning that States should
use all relevant analyses and not only
information that helps their case.
Response:
The EPA agrees with these
comments. The final modeling guidance
recommends supplemental analyses
(including weight of evidence) for all
attainment demonstrations. All States
should submit modeling, ambient data,
and emissions analyses in addition to
the primary modeling demonstration. A
weight of evidence analysis is needed if
the predicted future year PM
2.5
concentrations are slightly higher or
slightly lower than the NAAQS.
We also agree that a weight of
evidence demonstration should include
all relevant information, including
analyses which support attainment and
those that do not. The idea of the
analysis is to ‘‘weigh’’ the evidence,
both good and bad. That cannot be fairly
done if some evidence is not presented.
Comment:
Several commenters
suggested that a modeled attainment
demonstration should not be
specifically required. Instead they
suggest that all demonstrations should
be weight of evidence demonstrations.
This would include different analyses of
ambient data, trends, and modeling. But
due to the uncertainties in the current
PM
2.5
models and emissions data,
modeling would be but one part of a
broader weight of evidence approach.
Response:
We disagree with this
comment. Model results should be the
primary analysis of an attainment
demonstration. Regardless of current
uncertainties in the PM
2.5
models and
emissions, models are the only tool that
can predict future concentrations of
PM
2.5
. The uncertainties in the model
inputs and formulation should be taken
into account when evaluating the
results. We agree that a broad analysis
of modeling, ambient data and
emissions trends should be part of the
attainment demonstration. This is
reflected in the final modeling guidance.
4. Modeled Attainment Test
[Section III.F.4 of November 1, 2005
proposed rule (70 FR 66008)]
a. Background
The proposal described the nature of
the attainment tests for the annual
average and 24-hour average PM
2.5
NAAQS contained within the modeling
guidance. Both tests use monitored data
to estimate current air quality. The
attainment test for a given standard is
applied at each monitor location within
or near a designated nonattainment area
for that standard. There is also an
additional attainment test to be
performed in unmonitored areas.
Models are used in a relative sense to
estimate the response of measured air
quality to future changes in emissions.
Future air quality is estimated by
multiplying current monitored values
times modeled responses to changes in
emissions. Because PM
2.5
is a mixture of
chemical components, the guidance
recommends using current observations
and modeled responses of major
components of PM
2.5
to estimate future
concentrations of each component. The
predicted future concentration of PM
2.5
is the sum of the predicted component
concentrations.
b. Final Rule
The nature of the PM
2.5
attainment
tests is unchanged. The final modeling
guidance recommends refinements to
the test and discusses the treatment of
individual PM
2.5
species. The speciated
modeled attainment test (SMAT) that
was used to estimate future PM
2.5
concentrations for CAIR has been
(mostly) implemented in the final
guidance. Among the new
recommendations is to better account
for the known differences between the
PM
2.5
Federal Reference Method (FRM)
measurements and the PM
2.5
speciation
measurements. For example, it is
recommended to account for the
volatilization of nitrate from the FRM
filters and to account for uncertainties
in organic carbon measurements by
employing an ‘‘organic carbon by mass
balance’’ technique. This assumes that
all remaining mass not accounted for by
other species is organic carbon mass.
Additional details are contained in the
modeling guidance.
The guidance also recommends,
where necessary, to spatially interpolate
PM
2.5
species data to estimate the
species concentrations at FRM sites. It is
necessary to estimate species
concentrations when there are no
species measurements at FRM sites.
Several techniques can be used to
estimate species concentrations. Spatial
interpolation techniques may be useful
in many areas. In other cases, it may be
adequate to assume that data from a
speciation monitor may be
representative of multiple FRM
monitors. It is particularly important to
develop credible techniques to estimate
species concentrations at the locations
of the highest FRM monitors.
The guidance lists several techniques
that can be used. The EPA will provide
software which will apply the modeled
attainment test, using ambient data and
model outputs. Additionally, the
software will interpolate the PM
2.5
species data to allow application of
SMAT for all FRM monitors. The
software will be available at the same
location as the final modeling guidance
(
http://www.epa.gov/scram001/
guidance
_
sip.htm
).
Ultimately, it is up to the States to
determine the best method to represent
the PM
2.5
species concentrations, subject
to EPA’s review and approval. These
estimates are needed to perform the
modeled attainment test.
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c. Comments and Responses
Comment:
Several commenters were
concerned that interpolation of PM
2.5
species concentrations may not be
appropriate in certain areas or
situations. The concentrations can vary
significantly between urban and rural
areas and even between nearby urban
areas. One commenter suggested that it
might be useful to use older field study
measurements to derive current species
concentrations. Another commenter
suggested that it might be reasonable to
assume that speciation measurements
were representative of nearby FRM sites.
Response:
We agree that
interpolations of species data may not
always be the best way to estimate
species concentrations at FRM sites. The
modeling guidance lists several different
possible techniques. States should
review their data and situation and
choose the most reasonable
methodology to estimate species
concentrations. Nonattainment areas
that don’t have speciation
measurements at the highest FRM site(s)
need to be especially careful. The result
of the speciated attainment test can be
heavily influenced by the assumed
species concentrations at the highest
FRM sites. The attainment test will be
more straightforward in areas with
speciation monitors at the highest FRM
sites. States are also encouraged to place
speciation monitors at the highest FRM
sites. This will aid in future assessments
of attainment and ambient trends.
5. Multi-Pollutant Assessments
[Section III.F.5 of November 1, 2005
proposed rule (70 FR 66009)]
a. Background
The formation and transport of PM
2.5
is in many cases closely related to the
formation of both regional haze and
ozone. There is often a positive
correlation between measured ozone
and secondary particulate matter. Many
of the same factors affecting
concentrations of ozone also affect
concentrations of secondary particulate
matter. For example, similarities exist in
sources of precursors for ozone and
secondary particulate matter. Emissions
of NO
X
may lead to formation of nitrates
as well as ozone. Sources of VOC may
be sources or precursors for both ozone
and organic particles. Presence of ozone
itself may be an important factor
affecting secondary particulate
formation. The proposal recommended
multi-pollutant assessments for PM
2.5
attainment demonstrations. A multi-
pollutant assessment, or one-
atmosphere modeling, is conducted
with a single air quality model that is
capable of simulating transport and
formation of multiple pollutants
simultaneously. This type of model
simulates the formation and deposition
of PM
2.5
, ozone, and regional haze
components, and it includes algorithms
simulating gas phase chemistry,
aqueous phase chemistry, aerosol
formation, and acid deposition.
b. Final Rule
The recommendation to conduct
multi-pollutant assessments remains
unchanged. It is recommended to model
the impacts of future year control
strategies on PM
2.5
, ozone, and regional
haze. It may not always be possible or
convenient to do so, but it can be
beneficial to the strategy development
process.
PM
2.5
control strategies will have an
impact on regional haze, and will
possibly impact ozone. Even if high
ozone and high PM
2.5
concentrations
don’t typically occur during the same
time of the year, controls that affect
precursors to PM
2.5
may also affect
ozone (e.g. NO
X
). The SIP submittal
dates for PM
2.5
, ozone, and regional haze
do not currently line up. The PM
2.5
SIPs
are due almost 1 year later than ozone.
But States can still do modeling
analyses that can provide information
for multiple pollutants. States can use
one-atmosphere models that are capable
of simulating both ozone and PM
2.5
.
They can also try to use consistent
meteorological fields and emissions
inventories so that the same control
strategies are relatively easy to evaluate
for both ozone and PM
2.5
. Modeling the
same future year(s) for PM
2.5
and ozone
can also make it easier to evaluate the
impacts of controls on both pollutants.
It should be noted that there are no
specific modeling requirements other
than the recommendation to try to
harmonize the ozone, PM
2.5
, and
regional haze analyses whenever
possible.
c. Comments and Responses
Comment:
One commenter suggests
that multi-pollutant assessments may
not be beneficial because their area
experiences winter PM
2.5
exceedances
and summer ozone exceedances.
Response:
We disagree with the
comment. Even in situations where high
PM
2.5
and ozone don’t occur during the
same time of year, multi-pollutant
assessments may be helpful. NO
X
controls that may be needed to reduce
nitrates in the winter are likely to have
an impact on ozone in the summer. As
well, changes in VOCs may have an
impact on both PM
2.5
and ozone.
Running potential control strategies
through the same modeling platform for
ozone, PM
2.5
, and regional haze may
allow the development of optimized
strategies.
6. Which Future Year(s) Should Be
Modeled?
[Section III.F.6 of November 1, 2005
proposed rule (70 FR 66009)]
a. Background
Modeling analyses consist of base
year modeling and future year
modeling. The attainment test examines
the change in air quality between the
base and future years. The proposal
recommended, where possible, future
modeling years should be coordinated
so that a single year can be used for both
PM
2.5
and ozone modeling. This
coordination will help to reduce
resources expended for individual
modeling applications for PM
2.5
and
ozone and will facilitate simultaneous
evaluation of ozone and PM impacts.
Although there is some flexibility in
choosing the future year modeling time
periods, unless the State believes it
cannot attain the standards within 5
years of the date of designation and
must request an attainment date
extension, the choice of modeling years
for PM
2.5
cannot go beyond the initial 5
attainment period. Attainment date
extensions will only be granted under
certain circumstances. Among other
things, the State must submit an
attainment demonstration showing that
attainment within 5 years of the
designation date is impracticable.
b. Final Rule
Further information is now known
concerning the modeling years for
ozone. Moderate nonattainment areas
are presumed to be modeling 2009. This
is consistent with the last year of the 5
year period allowed under Subpart I for
PM
2.5
. Therefore, it is logical to presume
that areas that are able to attain the
PM
2.5
NAAQS within 5 years will model
a future year of 2009. Areas that won’t
be able to attain the standard in 5 years
will need to request an attainment date
extension (of up to 5 additional years).
The NAAQS must be attained as
expeditiously as practicable. Therefore,
attainment date extensions must contain
modeling analyses to justify the
extension. Details of the required
analyses are contained in the RACT and
RACM sections of the final rule. See
section F for more details.
F. Reasonably Available Control
Technology and Reasonably Available
Control Measures
This section of the preamble discusses
the final rule requirements for RACT
and RACM. In order to explain EPA’s
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approach in the final rule more clearly,
we first discuss the statutory and
regulatory background for the RACT and
RACM requirements, and we then
explain the key options and
interpretations upon which we took
comment in the proposal. Thereafter, we
discuss significant comments we
received on the proposal and provide
brief responses to those comments.
[Additional comments and responses
appear in the RTC for this final rule
located in the docket.] Most of the
comments received on this topic
addressed the three options EPA
proposed for the RACT requirement, the
relationship between the RACT
requirement and EPA’s Clean Air
Interstate Rule (CAIR), and the control
measures to be required or considered
for RACT and RACM.
1. Background on Statutory
Requirements for RACT and RACM
Subpart 1 of Part D of the CAA
(sections 171–179B) applies to all
designated nonattainment areas. Section
172 of this subpart includes general
requirements for all attainment plans.
Notably, Congress provided EPA and
States a great deal of deference for
determining what measures to include
in an attainment plan. Specifically,
Section 172(c)(1) requires that each
attainment plan ‘‘provide for the
implementation of all reasonably
available control measures as
expeditiously as practicable (including
such reductions in emissions from
existing sources in the area as may be
obtained through the adoption, at a
minimum, of reasonably available
control technology), and shall provide
for attainment of the national primary
ambient air quality standards.’’ By
including language in Section 172(c)(1)
that only ‘‘reasonably available’’
measures be considered for RACT/
RACM, and that implementation of
these measures need be applied only ‘‘as
expeditiously as practicable,’’ Congress
clearly intended that the RACT/RACM
requirement be driven by an overall
requirement that the measure be
‘‘reasonable.’’ Thus, the rule of ‘‘reason’’
drives the decisions on what controls to
apply, what should be controlled, by
when emissions must be reduced, and
finally, the rigor required in a State’s
RACT/RACM analysis. For example, we
previously stated that the Act ‘‘does not
require measures that are absurd,
unenforceable, or impractical’’ or result
in ‘‘severely disruptive socioeconomic
impacts’’ 55 FR 38327. Moreover, we
interpret the term ‘‘reasonably
available’’ to allow States to consider
both the costs and benefits of applying
the measure, and whether the measure
can be readily and effectively
implemented without undue
administrative burden. 66 FR 26969.
We also interpret the ‘‘reasonably
available control measures’’ in these
provisions as referring to measures of
any type that may be applicable to a
wide range of sources, whereas the
parenthetical reference to ‘‘reasonably
available control technology’’ refers to
measures applicable to stationary
sources. RACM can apply to mobile
sources, areas sources and stationary
sources not already subject to PM
2.5
RACT requirements. Thus, RACT is a
type of RACM specifically designed for
stationary sources. As noted above,
States are required to implement RACM
and RACT ‘‘as expeditiously as
practicable’’ as part of attainment plans
designed to attain the standards.
20
Section 172 does not include any
specific applicability thresholds to
identify the size of sources that States
and EPA must consider in the RACT
and RACM analysis. Nor, does Section
172 specifically indicate which
pollutant(s) or precursor(s) must be
subject to RACM or RACT measures to
attain the NAAQS. Other pollutant-
specific provisions of the CAA do
include applicability thresholds
pertaining to attainment plan
requirements for NAAQS and precursor
pollutants. For example, subpart 2 of
part D, which establishes additional
requirements for ozone nonattainment
areas, establishes thresholds ranging
from 100 to 10 tons per year for
requirements applicable to ‘‘major
sources’’ or ‘‘major stationary sources,’’
depending on the area’s classification or
level of nonattainment. Subpart 4 of part
D, which provides additional plan
requirements for PM
10
nonattainment
areas, establishes thresholds of 100 and
70 tons per year for requirements
applicable to a ‘‘major source’’ or ‘‘major
stationary source.’’
Moreover, subpart 1, unlike subparts
2 and 4, does not identify specific
source categories for which EPA must
issue control technology documents or
guidelines, or identify specific source
categories for State and EPA evaluation
during attainment plan development.
For ozone, subpart 2 contains a list of
specific requirements for control
techniques guidelines (CTGs) and
alternative control techniques (ACT)
documents. For PM
10
, section 190 of the
CAA (in subpart 4) places particular
emphasis on specific sources of area
emissions, but does not identify specific
20
Under the Tribal Air Rule (TAR), requirements
for RACT and RACM may be considered to be
severable elements of implementation plan
requirements for Tribes.
stationary source categories for which
RACT guidance must be issued. Section
190 requires EPA to develop RACM
guidance documents for residential
wood combustion, silvacultural and
agricultural burning, and for urban
fugitive dust control.
2. What Is the Overall Approach To
Implementing RACT and RACM in the
Final Rule?
a. Background for RACT
Since the 1970s, EPA has interpreted
RACT to mean ‘‘the lowest emissions
limitation that a particular source is
capable of meeting by the application of
control technology that is reasonably
available considering technological and
economic feasibility’’ as well as other
considerations.
21
Presumptive RACT
has been described as the norm
achievable by the source category.
22
Section 110 of the 1970 Clean Air Act
required States to develop SIPs
providing for attainment of the NAAQS
by 1975 or 1977. A number of areas
were having difficulty with developing
attainment plans, particularly for the
ozone standard. In response to the
implementation needs of this time
period, EPA introduced the term
‘‘RACT’’ in a 1976 memorandum from
Roger Strelow, Assistant Administrator
for Air and Waste Management to
Regional Administrators, ‘‘Guidance for
Determining Acceptability of SIP
Regulations in Non-attainment Areas’’
(Dec. 9, 1976). In this early guidance
relating to the acceptability of SIP
regulations, we indicated that our
overriding concern in approving SIPs
was attaining the particular NAAQS as
expeditiously as practicable through
reasonably available control technology
and other reasonably available control
measures. ‘‘The basis for fully approving
state-submitted SIP regulations
continues to be demonstrated
attainment and maintenance of all
national ambient air quality standards
as expeditiously as practicable,’’ the
memo stated.
The 1977 Clean Air Act amendments
added Part D to Title I of the Act, and
for the first time the Act specifically
called for EPA to designate
nonattainment areas and for SIPs to
require RACT and RACM in those
nonattainment areas. In a 1979
Federal
21
See, 44 FR 53782, September 17, 1979, and
1976 memorandum from Roger Strelow, Assistant
Administrator for Air and Waste Management to
Regional Administrators, ‘‘Guidance for
Determining Acceptability of SIP Regulations in
Non-attainment Areas’’ (Dec. 9, 1976).
22
See e.g. Workshop on Requirements for Non-
attainment Area Plans—Compilation of
Presentations (OAQPS No. 1.2–103, revised edition
April 1978).
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notice, EPA noted its view that
Congress adopted EPA’s pre-existing
conception of RACT in the 1977
amendments. (44 FR 53782, September
17, 1979). Also during the late 1970s,
EPA developed a number of new control
techniques guideline (CTG) documents
as directed in the 1977 amendments.
These CTGs provided States with
information on controls for a number of
categories of sources emitting VOCs,
and recommended a ‘‘presumptive
norm’’ for State RACT determinations
based on the control levels achievable
by sources in a given industry. CTGs
reduced the burden on States by
eliminating the need for each State to
develop its own technical support for
implementing the RACT requirement.
Since the CTG-recommended controls
were based on general capabilities of an
industry, EPA in the 1979 guidance (44
FR 53782) urged States in setting RACT
to judge the feasibility of the
recommended controls on particular
sources, and to adjust accordingly.
As noted above, EPA’s early guidance
related to the RACT requirement
indicated that our overriding concern in
approving State RACT requirements was
attaining the particular NAAQS. We
initially required States to apply RACT
to qualify for attainment extensions, and
in some cases, for plans that could not
demonstrate attainment.
During the 1980s, EPA implemented
the RACT requirements with a number
of CTGs and guidance documents.
These materials were aimed at
addressing the attainment deadlines of
1982 and 1987 under the 1977 Clean Air
Act amendments. During this time, EPA,
for pollutants other than ozone,
considered RACT to be dependent upon
reductions needed for attainment as
expeditiously as practicable. For ozone,
where the State performed
photochemical grid modeling, the
approach was the same, but where the
State used less sophisticated tools, we
considered RACT to be independent of
whether the controls were needed to
reach attainment as expeditiously as
practicable. We took this alternate
approach because of concerns related to
the precision of modeling techniques. In
other words, in those cases, we required
that a stationary source of the requisite
type and size be subject to RACT,
whether or not such controls were
actually demonstrated to be necessary
for the area to attain by its specified
date. (44 FR 20375–20376, April 4,
1979)
Congress followed a similar approach
in the 1990 amendments to the CAA for
purposes of the ozone NAAQS in the
subpart 2 provisions added at that time.
For example, section 182(b)(2) requires
the imposition of RACT controls for all
VOC source categories covered by a CTG
and for all other major stationary
sources of VOC located within certain
nonattainment areas. Thus, Congress
required these controls without
allowing for an area-specific
demonstration by the State that the area
needed the controls for attainment as
expeditiously as practicable. Extensive
discussion of this requirement appeared
in the 1992 general preamble (57 FR
13541), in which EPA provided
guidance for implementation of the
ozone NAAQS.
Notably, Congress did not
significantly amend the generally
applicable provisions for nonattainment
areas that appear in subpart 1 of Part D
in 1990. This indicates that Congress
intended that the Agency retain the
authority to interpret the generally
applicable nonattainment area plan
requirements of section 172(c),
including the RACT and RACM
requirements, in the way that is most
appropriate for new NAAQS that are
subject to subpart 1. As discussed
below, EPA has determined that an
approach to the RACT requirement in
which RACT varies in different
nonattainment areas based on the
reductions needed for attainment as
expeditiously as practicable, is
appropriate for implementation of the
PM
2.5
NAAQS. We believe that the
improved ability to model air quality
impacts of emissions controls allows for
this approach.
b. Proposed Options for RACT
The EPA proposed and requested
comment on three alternative
approaches for interpretation of the
RACT requirement of section 172(c)(1)
for implementation of the PM
2.5
NAAQS. The EPA proposed these
approaches in order to evaluate which
method would best ensure that States
consider and adopt RACT measures for
stationary sources in a way that is
consistent with the overarching
requirement to attain the standards as
expeditiously as practicable, while
providing flexibility for States to focus
regulatory resources on those sources of
emissions that contribute most to local
PM
2.5
nonattainment.
Under the first proposed alternative,
EPA would require States to conduct a
RACT analysis and to identify and
require reasonably available controls for
all affected stationary sources in the
nonattainment area, comparable to the
implementation of RACT provided in
subpart 2 governing implementation of
the 1-hour ozone NAAQS. Under this
option, covered sources would be
required to apply reasonable available
controls considering technical and
economic feasibility, and there would
be no opportunity for States to excuse
stationary sources from control on the
basis that the emissions reductions from
those controls would not be necessary to
meet RFP requirements or to reach
attainment. Under this alternative, EPA
proposed to limit the universe of
sources for which States must conduct
a RACT analysis and impose RACT
controls, by providing an applicability
threshold based upon the amount of
emissions potentially emitted by the
sources. Under this first option, EPA
requested comment on a number of
alternative emissions applicability
thresholds.
Under the second proposed
alternative, EPA would require States to
conduct a RACT analysis and to identify
reasonably available controls for all
affected stationary sources. Under this
option, however, States could thereafter
determine that RACT does not include
controls that would not otherwise be
necessary to meet RFP requirements or
to attain the PM
2.5
NAAQS as
expeditiously as practicable.
23
Under
this approach, RACT would be
determined as part of the broader RACM
analysis and identification of all
measures—for stationary, mobile, and
area sources—that are technically and
economically feasible, and that would
collectively contribute to advancing the
attainment date.
24
Because RACT and
RACM are considered together under
this alternative, we did not propose
emissions threshold options for
evaluation of stationary source RACT. In
addition, consistent with existing
policies, States would be required to
evaluate the combined effect of
reasonably available measures to
determine whether application of such
measures could advance the attainment
date by at least one year.
25
The third proposed alternative, EPA’s
preferred option in the proposal,
combined the first two options and is
similar to the RACT approach adopted
in the final implementation rule for the
8-hour ozone program. Under the third
option, EPA would require States to
conduct a RACT analysis and to require
reasonably available controls for all
affected stationary sources in
23
Under the Tribal Air Rule (TAR), requirements
for RACT and RACM may be considered to be
severable elements of implementation plan
requirements for Tribes.
24
In
Sierra Club
v.
EPA
, 294 F.3d 155 (D.C. Cir.
2002), the court stated in upholding EPA’s statutory
interpretation of RACM that the Act does not
compel a state to consider a measure without regard
to whether it would expedite attainment.
25
In this notice, where we use the shorthand
phrase ‘‘advance the attainment date,’’ it means
‘‘advance the attainment date by one year or more.’’
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nonattainment areas with attainment
dates more than 5 years from the date
of designation. For areas with an
attainment date within 5 years of
designation (e.g. by April 5, 2010 for
areas with an effective date for
designation of April 5, 2005), EPA
would require RACT as under the
second proposed alternative, in which
RACT would be determined as part of
the broader RACM analysis. For these
areas, States could determine that RACT
does not include controls that would
not otherwise be necessary to meet RFP
requirements or to attain the PM
2.5
NAAQS as expeditiously as practicable.
The same proposed suboptions with
respect to the size of sources for
consideration under the first alternative
were also included under this
alternative.
c. Proposed Approach for RACM
The EPA proposed and asked for
comment on one approach for
interpreting the RACM requirement for
PM
2.5
. The EPA based the proposal on
the approach that we adopted for other
NAAQS implementation programs.
Under this approach, a State provides a
demonstration in its SIP that it adopted
all reasonably available measures
needed to meet RFP requirements and to
attain the standard as expeditiously as
practicable and that no reasonably
available additional measures would
advance the advance the attainment
date by at least 1 year or would be
necessary to meet the RFP requirement
for the area.
26
Under section 172(a)(2), the state
implementation plan must provide for a
nonattainment area to attain as
expeditiously as practicable, but no later
than 5 years after the effective date of
designation of the area (e.g., no later
than April 2010 for the final
designations effective April 2005). The
statute thus creates a presumption for
attainment within 5 years of designation
unless certain statutory criteria are met
for an extension of the attainment date.
Under the proposed approach to RACM
for PM
2.5
, each State would evaluate
available measures for sources of PM
2.5
or its regulatory precursors in the area
to determine if reasonable measures
were needed to meet the RFP
requirement or to achieve attainment as
expeditiously as practicable. If modeling
of all RACM and other state, regional
26
In the context of the PM
10
NAAQS, EPA has
concluded that ‘‘advancement of the attainment
date’’ should mean an advancement of at least one
calendar year.
See
State Implementation Plans;
General Preamble for the Implementation of Title I
of the CAA Amendments of 1990, 57 FR 12498
(April 16, 1992).
See also Sierra Club
v.
EPA,
294
F.3d 155 (D.C. Cir. 2002).
and federal measures indicates that the
State will not be able to demonstrate
attainment within 5 years after
designation based upon the severity of
nonattainment in that area or the
availability or feasibility of
implementing controls in that area, then
the State may request an attainment date
extension. We proposed that under
these circumstances, the EPA could
extend the attainment date for a period
of 1 to 5 years, when the State shows
that it will implement all RACT and
RACM as expeditiously as practicable,
has met its obligation to address
intrastate pollution transport from
sources within its jurisdiction, and still
needs additional time to attain.
In the proposed rule, the EPA also
took comment on the following overall
steps for implementing the statutory
requirement for RACM.
(1)
Identification of measures.
The
State would begin the process of
determining RACM by identifying all
available control measures for all
sources of PM
2.5
and its precursors in
the nonattainment area. The RACM can
apply to mobile sources, area sources,
and stationary sources.
(2)
Evaluation of measures.
After the
State identifies the universe of available
measures for the sources in the area, the
State would evaluate them to determine
whether implementation of such
measures is technically and
economically feasible, and whether the
measure will contribute to advancing
the attainment date.
(3)
Adoption of measures.
The State
would adopt all reasonably available
measures for the area consistent with
meeting the applicable RFP
requirements and attaining the NAAQS
as expeditiously as practicable, in
accordance with applicable policy and
guidance for attainment demonstrations.
We would then approve or disapprove
the State’s plan through notice and
comment rulemaking. We also noted
that in reviewing the State’s selection of
measures for RACM, or determining that
certain measures are not RACM, EPA
may independently supplement the
rationale of the State or provide an
alternative reason for reaching the same
conclusion as the State.
c. Final Rule
The EPA carefully considered our
interpretation of section 172(c)(1) for the
PM
2.5
NAAQS. Because of the variable
nature of the PM
2.5
problem in different
nonattainment areas, which may require
States to develop attainment plans that
address widely disparate circumstances
(e.g., different source types and mixes,
different precursors and mixes of
precursors, and different meteorological
conditions), we determined that the
regulations implementing the PM
2.5
NAAQS should provide for a great
degree of flexibility with respect to the
RACT and RACM controls.
Selected approach to RACT and
RACM.
The final rule reflects EPA’s
decision to select option 2 for RACT and
to require a combined approach to
RACT and RACM. Under this approach,
RACT and RACM are those measures
that a State finds are both reasonably
available and contribute to attainment
as expeditiously as practical in the
specific nonattainment area.
By definition, measures that are not
necessary either to meet the RFP
requirement, or to help the area attain
the NAAQS as expeditiously as
practicable, are not required RACT or
RACM for such area. The EPA believes
that this approach provides the greatest
flexibility to a State to tailor its SIP
control strategy to the needs of a
particular PM
2.5
nonattainment area, but
it may require the State to conduct a
more detailed analysis to identify the
most effective RACT/RACM strategy to
attain the NAAQS.
During the comment period,
commenters raised concerns that this
approach may be overly burdensome on
States because of the number of
potential control measures a State
would need to consider. Today, we
clarify that although the State must
conduct a thorough analysis of
reasonably available measures, States
need not analyze every conceivable
measure, as explained in the guidance
below. Instead, ‘‘reason’’ should drive
States identification of potential
measures, but States should remain
mindful of the public health risks of
PM
2.5
. As long as a State’s analysis is
sufficiently robust in considering
potential measures to ensure selection
of all appropriate RACT and RACM, and
the State provides a reasoned
justification for its analytical approach,
we will consider approving that State’s
RACT/RACM strategy.
Guidance on State analysis to identify
RACT, RACM and appropriate
attainment date.
A State must consider
RACT and RACM for all of its
nonattainment areas. However, EPA
believes that if the State projects that an
area will attain the standard within 5
years of designation as a result of
existing national measures (i.e.
projected to have a design value of 14.5
or lower), then the State may conduct a
limited RACT and RACM analysis that
does not involve additional air quality
modeling. A limited analysis of this
type would involve the review of
reasonably available measures, the
estimation of potential emissions
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reductions, and the evaluation of the
time needed to implement these
measures. If the State could not achieve
significant emissions reductions during
2008 due to time needed to implement
the potential measures or other relevant
factors, then the State and EPA could
conclude that there are no further
reasonably available control measures
for that area that would advance the
attainment date by one year or more
relative to the presumptive outer limit
for attainment dates, i.e., 5 years from
designation. In lieu of conducting air
quality modeling to assess the impact of
potential RACT and RACM measures,
States may consider existing modeling
information to determine the magnitude
of emissions reductions that could
significantly affect air quality and
potentially result in attaining prior to
2010 (e.g. in 2009 based on 2006–8 air
quality data). If the State, in
consultation with EPA, determines from
this initial, limited RACT and RACM
analysis that the area may be able to
advance its attainment date through
implementation of reasonable measures,
then the State would conduct a more
detailed RACT and RACM analysis,
including appropriate air quality
modeling analyses, to assess whether it
can advance the attainment date.
In general, the combined approach to
RACT and RACM in the final rule
includes the following steps: (1)
Identification of potential measures that
are reasonable; (2) modeling to identify
the attainment date that is as
expeditious as practicable; and (3)
selection of RACT and RACM.
Identification of potential measures.
The State’s review of potential measures
must be sufficient to identify all
appropriate RACT and RACM. As stated
previously, inherent to RACT/RACM is
the basic requirement that the measure
be ‘‘reasonable.’’ A State need not
evaluate measures in its RACM/RACT
analysis that it determines are
unreasonable such as measures that are
‘‘absurd, unenforceable, or impractical’’
or that would cause ‘‘severely disruptive
socioeconomic impacts, (e.g. gas
rationing and mandatory source
shutdowns); such measures are not
required by the Act. 55 FR 38327.
As we also stated earlier, a State’s
RACT/RACM analysis not only involves
an assessment about what emissions
sources to control and to what level, but
also a judgment as to when it is
reasonable to require a sector to comply
with a given measure. Accordingly, if
the State or Federal rules already
heavily regulate a given sector, it is
reasonable for the State to first look to
unregulated parts of the sector for
RACT/RACM measures, especially, in
light of costs already realized by the
regulated sector. A State may conclude
that it is unreasonable to further
regulate the industry, or that it is only
reasonable to impose measures in the
latter years of the attainment plan.
Finally, the State should use reason in
the extent of its efforts to identify
potential control measures. For
example, if a review of monitoring data
and modeling studies indicates that
reductions in SO
2
are much more
effective in reducing ambient PM
2.5
than
reductions in other pollutants, we
expect that the State will more
vigorously identify RACT/RACM
measures for SO
2
than for other
pollutants. Conversely, if reductions in
a given pollutant, even in large
quantities, would have trivial impacts
on PM
2.5
, less rigor is needed in the
State’s assessment of controls for that
pollutant, because such controls could
not contribute to advancing the
attainment date. Likewise, where
reducing emissions of a pollutant is
effective in reducing ambient PM
2.5
, if
the emissions inventory for that
pollutant is dominated by a given type
of emissions source, then it would be
appropriate to focus the analysis on
measures for that segment of the
inventory. No RACT/RACM analysis is
needed for pollutants that are not
attainment plan precursors for a
particular PM
2.5
nonattainment area.
As supporting information for
identification of RACT and RACM, the
State ordinarily provides data on
technologically feasible control
measures:
—A list of all emissions source
categories, sources and activities in
the nonattainment area (for multi-
State nonattainment areas, this would
include source categories, sources and
activities from all states which make
up the area)
—For each source category, source, or
activity, an inventory of direct PM
2.5
and precursor emissions;
—For each source category, source, or
activity, a list of technologically
feasible emission control technologies
and/or measures
27
27
The EPA believes that it is not necessary to
identify every possible variation of every type of
control measure, or all possible combinations of
technologies and measures that would apply to a
given source or activity if the State has properly
characterized the potentially available emissions
reductions and their costs. For example, EPA
believes that the State can conduct a thorough
analysis of VMT reduction measures without
including every possible level or stringency of
implementation of certain possible measures or
combinations of measures for reducing VMT, so
long as those measures would not affect the overall
assessment of VMT reduction capabilities and the
associated costs.
—For each technologically feasible
emission control technology or
measure, the State should provide the
following information: (1) The control
efficiency by pollutant; (2) the
possible emission reductions by
pollutant; (3) the estimated cost per
ton of pollutant reduced; and (4) the
date by which the technology or
measure could be reasonably
implemented.
Based on this and other relevant
information, the State will identify the
reasonable measures (potential RACT
and RACM) to be included in air quality
modeling. (At its option, the State may
prefer not to make a judgment on
whether certain measures are
technically and economically feasible, if
it believes they will not contribute to
earlier attainment. In that case, the State
could include those measures in the
modeling, and later exclude them from
RACT and RACM by showing that all
the excluded measures together would
not advance the attainment date by at
least 1 year.) As previously mentioned,
in determining the attainment date that
is as expeditious as practicable, the
State should consider impacts on the
nonattainment area of intrastate
transport of pollution from sources
within its jurisdiction, and potential
reasonable measures to reduce
emissions from those sources.
Modeling to determine the attainment
date that is as expeditious as
practicable.
Second, for purposes of
determining the attainment date that is
as expeditious as practicable, the State
will need to conduct modeling to show
the combined air quality impact of all of
the potential measures identified in the
first step with a modeling analysis for
the year 2009. A base case scenario for
the year 2009 would project future air
quality given implementation of existing
measures (Federal, State and local). If
this base case scenario demonstrates
attainment by 2010, then the State must
demonstrate why attainment could not
be achieved in an earlier year. (As noted
above, given the April 2008 due date for
SIP submissions, it may be difficult to
achieve earlier attainment in many
cases).
If the base case scenario does not
demonstrate attainment, then a control
case scenario (described below) is
needed to examine whether the
reasonable, technically and
economically feasible measures
identified by the State would result in
attainment in 2009. The control case
scenario would add potential SIP
measures—e.g. potential RACT/RACM,
plus any candidate intrastate transport
measures that the State has identified
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and would be feasible to implement by
that year. States in multi-State
nonattainment areas are strongly
encouraged to collaborate on their
modeling analyses. This modeling,
along with other information known as
weight of evidence considerations,
would inform a judgment as to whether
reasonable measures could lead to
attainment of the standards within 5
years after designation. If the analysis
does not demonstrate attainment by
April 2010 (2009 analysis year), then the
analysis would serve as the technical
basis for the State to seek an extension
of the attainment date for that area.
Further analysis would then be
necessary and is required to identify the
specific attainment date.
The choice of future years to model
beyond 2010 may vary from area to area.
Often, modeling potential controls in
two different future years may be
necessary to support a judgment that a
projected attainment year is as
expeditious as practicable. If the area is
projected to remain over the standard in
the early projection year (e.g., 2009)
despite the emission reductions from
the modeled control measures, but is
projected to be well below the standard
in the later projection year (e.g., 2012),
interpolation and emission inventory
analysis could identify an intermediate
year as the appropriate attainment date.
There may be cases in which modeling
a single year is sufficient because
modeling of all technically and
economically feasible controls results in
attainment by a narrow margin in that
year.
For many areas, EPA modeling
analysis for CAIR and other modeling
analyses that have been performed
suggest a number of nonattainment
areas will have a modest amount (in
some cases only a few tenths of a
microgram) of needed reductions in
ambient levels after 2010 to reach
attainment. For any such area, and for
areas otherwise expected to attain
relatively soon after 2010 (for example,
due to substantial reductions in a
dominant local source), EPA believes
that this analysis should be for a year no
later than 2012. A later date (e.g., 2014)
may be appropriate for areas with very
high PM
2.5
levels that face difficulty
attaining within 10 years.
The EPA believes that it is not
reasonable to require States to model
each and every year between 2009 and
2014 to determine the appropriate
attainment date. Modeling future year
inventories is a time consuming and
resource intensive process. Multiple
models and pre-processors are needed
in order to generate year specific
emissions for the various emissions
sectors (e.g. mobile, non-road, non-EGU
point, EGU point, etc.). Because it is not
reasonable to model every year, a logical
choice often may be to model a year in
the middle of the period. As such, we
recommend modeling an emissions year
no later than 2012 as the initial
extension date (which translates to a
2013 attainment date). If this modeling
indicates that the area can reach
attainment by 2012, then the State can
further analyze emissions and strategies
to determine if the attainment date can
be advanced to an earlier year. If the
modeling indicates that the area cannot
reach attainment by 2012, then the
modeling will serve as further
justification for granting a longer
attainment date extension (e.g.,
attainment date of 2015 with modeling
for 2014). In that case, additional
modeling of 2014 with further emissions
controls would be required in order to
show attainment. Again, the State
should then further analyze emissions
and strategies to determine if the
attainment date can be advanced to an
earlier year between 2012 and 2015.
Additionally, in the discussion of air
quality modeling issues in section II.E
above, we discuss the benefits of
addressing control strategies for
multiple pollutants. Part of the
challenge of multi-pollutant modeling is
coordinating the future modeling years
for different pollutants in order to
minimize the number of required future
year model runs. As part of the
requirements of the 8-hour ozone
implementation rule, States are
currently working on modeling analyses
for 2009 and in some cases for 2012
(serious nonattainment areas). For an
area that cannot attain the PM
2.5
NAAQS by 2010, this may be reason to
select 2012 as the year to model, so that
the State could conduct the modeling
for both ozone and PM
2.5
in tandem.
This would, in some cases, allow the
pooling of resources (e.g., inventories,
model runs, etc.) and provide for faster
development of a PM
2.5
attainment
demonstration.
It may also be possible for the State
to look at 2009 and 2014 only. In this
instance, the State may find sufficient
data to interpolate results for the years
in between based on estimated changes
in emissions.
We emphasize that when a State
models later years, that this analysis
must take into account potential
controls that the State may have
determined would not be RACT or
RACM for an earlier year. For example,
some measures that are impractical to
implement by 2009 could be reasonable
if implemented by 2010, 2011 or 2012.
Thus, when the State models later years,
the list of potential controls should be
expanded to include technically and
economically feasible measures that can
be implemented by the analysis year.
Selection of RACT & RACM.
Based on
this analysis, the State should make
decisions on RACT, RACM, intrastate
measures, and the attainment date that
is as expeditious as practicable. Because
EPA is defining RACT and RACM as
only those reasonable, technically and
economically feasible measures that are
necessary for attainment as
expeditiously as practicable, the State
need not adopt all feasible, reasonable
measures. The State may exclude those
reasonable measures that, considered
collectively, would not advance the
attainment date.
Comments and Responses
Comment:
A number of commenters
generally supported EPA’s second
proposed alternative to RACT (option
2). Most of these commenters expressed
concern that the other options would
require the imposition of controls
whether or not they were needed to
attain the PM
2.5
standards as
expeditiously as practicable. Some State
and local commenters also urged EPA to
select option 2 as the best interpretation
of the RACT requirement for PM
2.5
because they believe that it will be the
most appropriate approach for designing
attainment strategies for their particular
nonattainment area or areas.
Response:
The EPA agrees that these
two points are important considerations.
After carefully considering the options,
we concluded that Option 2 was the
most suitable approach for the PM
2.5
NAAQS. Options 1 and 3 do not reduce
the States’ burden to analyze potential
control measures as the States would
still be required to look beyond the
mandated RACT for reasonably
available control measures (RACM).
Moreover, Options 1 and 3 could
require imposition of controls on some
sources that would not strictly be
necessary to attain the NAAQS as
expeditiously as practicable. Given the
nature of the PM
2.5
nonattainment
problem, EPA concluded that an
interpretation that provides the
maximum flexibility is a better
approach.
Comment:
Some commenters
recommended that EPA modify
proposed option 2 to include a tons-per-
year threshold. Under such an
approach, the States and EPA would
only require RACT for sources whose
emissions were above the threshold.
Most of these comments recommended
a RACT threshold of 100 tons per year.
These commenters expressed concern
that if option 2 were implemented
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without such a threshold, States would
be burdened with conducting RACT
analyses for very small sources or
source categories with low emissions.
Response:
The EPA believes that
under the approach chosen for the final
rule in which RACT is considered to be
a part of the overall RACM process, it
would be difficult to define a threshold
that would apply for all types of sources
and for all types of control measures in
all nonattainment areas. It has not been
common practice under past EPA policy
to establish or use an emissions
threshold when considering sources for
possible emission reductions as part of
a RACM analysis to show attainment as
expeditiously as practicable. Indeed,
many of the control technique
guidelines for VOC RACT do not
recommend an emissions threshold. A
state needing significant emission
reductions to attain the standards in a
given area even by 2015 would likely
conclude that controls should be
considered on smaller sources. In
contrast, a State with an area that
exceeds the standard by only a few
tenths of a microgram per cubic meter
may not need to consider controls on
smaller source to reach attainment as
expeditiously as practicable. The EPA
has selected option 2 for interpretation
of the RACT requirement for PM
2.5
, in
part, specifically because that approach
contemplates that States will conduct an
appropriate analysis of the spectrum of
source categories and potential controls
available. To cut off such analysis at a
set emissions-based cut point for all
sources and all areas would undermine
one of the key benefits of the approach.
Accordingly, EPA disagrees with
comments that option 2 should include
a nationally-defined threshold for the
size of sources or source categories that
require RACT analyses.
Comment:
A number of commenters
supported EPA’s first and third
proposed alternative approaches to
RACT (option 1 and option 3).
Commenters supporting these two
options used similar reasoning.
Commenters cited the statutory
language in section 172(c)(1) requiring
that the attainment plan provide for ‘‘at
a minimum’’ the adoption of RACT.
Accordingly, these commenters argued
that RACT is an independent, minimum
requirement of attainment plans
irrespective of the attainment
demonstration and that option 2, which
would not require the adoption of RACT
for all sources, has no policy or legal
justification. Other commenters noted
that option 1 would be much easier to
implement, because RACT would be
defined according to technical
reasonableness and would not hinge on
complicated determinations involving
attainment demonstrations. Some
commenters argued that option 1
provides for greater equity, because
similar measures would be required for
similar sources for all nonattainment
areas. Finally, some commenters
believed that it is inherently
inconsistent to assert that plans have
met the requirement for attainment ‘‘as
expeditiously as practicable’’ without
applying RACT to all major sources.
Response:
The EPA disagrees with
these comments. The EPA believes that
option 2 is fully consistent with section
172(c)(1). Section 172(c)(1) requires that
attainment plans must provide for the
implementation of RACM as
expeditiously as practicable (including
such reductions in emissions from
existing sources in the area as may be
obtained through the adoption, at a
minimum, of RACT). Contrary to the
commenters’ assertions, this language
does not demonstrate that RACT is
required for all sources, independent of
RACM and attainment demonstrations.
Moreover, this provision does not
require RACT whether or not imposition
of technology would advance the
attainment date. Instead, section
172(c)(1) explicitly provides that RACT
is included within the definition of
RACM, and EPA has previously
determined that the CAA only requires
such RACM as will provide for
attainment as expeditiously as
practicable. (See 57 FR 13498, 13560).
The courts have deferred to this
interpretation and concluded that EPA
interprets RACM as a collection of
reasonable measures that would
advance the attainment date. See
Sierra
Club
v.
EPA
, 294 F.3d 155, 162 (D.C.
Cir. 2002); see also
Sierra Club
v.
EPA
,
314 F.3d 735, 744 (5th Cir. 2002). The
CAA does not ‘‘compel [ ] a State to
consider whether any measure is
‘reasonably available’ without regard to
whether it would expedite attainment in
the relevant area.’’
Sierra Club
v.
EPA
,
294 F.3d at 162. The EPA concludes that
because section 172(c)(1) establishes
that RACT is a part of RACM, EPA is
reasonably applying the same
interpretation to the RACT requirement
for PM
2.5
. The RACT is a part of the
collection of measures that are
necessary to reach attainment as
expeditiously as practicable. It is thus
directly related to what a specific area
needs to attain the NAAQS, and States
need not implement reasonably
available measures that would not
advance the attainment date as part of
the PM
2.5
RACT requirement.
The EPA also finds that option 2 is
consistent with the statutory language
providing that a State must apply RACT
to existing sources, ‘‘at a minimum,’’ to
meet its requirement to apply RACM.
We interpret the ‘‘at a minimum’’ clause
to mean that when a State determines
that control of a specified existing
stationary source(s) is necessary to
attain, the State must apply RACT to
that source. Further, EPA believes this
requirement for RACT applies to
stationary sources as a group, and not to
each stationary source.
The EPA finds sound policy reasons
for choosing option 2. While an
approach that provided for application
of the same controls in all areas would
provide for more equity across areas,
EPA emphasizes that equity is only one
of many factors considered by EPA
when deciding between options 1, 2 and
3. The EPA believes that it is also
important to ensure that control
strategies focus on the most effective
measures with the greatest possibility
for significant air quality improvements.
In addition, while EPA agrees that
options 1 and 3 could provide for
greater ease of implementation, this is
also only one of the factors EPA
considered when deciding between the
proposed options. Under option 2,
States have a greater burden and
responsibility to identify the local
strategy that is tailored to their
particular air quality problem. At the
same time, the States have the ability to
identify the sources with the greatest
impact on nonattainment and to identify
a sound strategy that achieves
attainment in the most sensible manner.
The EPA believes that approaching
RACT and RACM in this manner is
consistent with the overall philosophy
imbedded in the SIP program since its
inception in the late 1960s and early
1970s.
Comment:
Some commenters believed
that the proposed RACM requirement
was too broad. These commenters
believed that the requirement to analyze
the entire ‘‘universe’’ of possible
measures was too burdensome for
States. Commenters felt this was
especially true in light of the lack of
federally issued CTG and ACT
documents for PM
2.5
and its precursors
for all potential source categories.
Response:
As explained earlier, States
should apply ‘‘reason’’ in identifying
measures to evaluate as potential
RACM/RACT. We recognize that States
are implementing the PM
2.5
standard for
the first time, and do not have the long
history and experience in implementing
PM
2.5
as they have in implementing the
PM
10
and ozone standards. Accordingly,
we expect that both the States and EPA
will expend extra effort in developing
and evaluating attainment plans that
contain appropriate controls. A number
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of resources exist to provide States with
information on potential control
measure costs and emissions reductions.
We intend to facilitate the sharing of
information through a control measure
website and other efforts, and expect
that States will develop screening
methods to reduce the burden of
analysis.
Comment:
One commenter asserted
that EPA should not require the analysis
for, or implementation of, RACT and
RACM for sources throughout the entire
nonattainment area, and should permit
States to focus only on sources located
in smaller specific ‘‘problem areas’’
within the nonattainment area.
Response:
The EPA designated areas
nonattainment based upon analysis of
the geographic area with sources that
‘‘contribute’’ to the violation of the
NAAQS in the area, in accordance with
section 107(d). These designations are
based upon, among other things, a
network of monitors that the State and
EPA previously agreed represented the
ambient air concentrations throughout
the area. Additional analysis of
information during the designation
process indicated those areas that
contributed to the violations at the
violating monitor because of, among
other things, the amount of emissions in
such adjoining areas. Accordingly, the
State in which a nonattainment area is
located must evaluate the full range of
sources of PM
2.5
and its precursors
throughout the designated
nonattainment area during the
development of the SIP. The EPA agrees
that there are some nonattainment areas
where one or a few large emissions
sources may be causing localized
concentrations at a monitor that are
much higher than those within the
remainder of the nonattainment area.
For such areas, the nonattainment
strategy will likely not succeed without
addressing those sources. The EPA does
not, however, believe it is acceptable
that the nonattainment strategy focus
only on those sources, because
additional reductions within the
nonattainment area would still have the
potential to advance the attainment
date. Exempting portions of the
nonattainment area could expose a
portion of the public residing
downwind in the area to exposure to
levels of PM
2.5
that exceed the NAAQS
for longer than necessary, and the health
detriments from such exposure, merely
to minimize the impact of having to
impose control strategies on sources
upwind. Moreover, to the extent that
monitoring in one portion of a
nonattainment area indicates violations
in multiple portions of the area, a
strategy that solely focused upon the
sources in the immediate vicinity of the
monitor might fail to assure that the
NAAQS is achieved throughout the
area. Because NAAQS violations
generally reflect a combination of
regional scale, metropolitan scale, and
local scale impacts, and all three scales
must be addressed, EPA requires RACT/
RACM submittals to address sources
throughout the nonattainment area.
Comment:
Some commenters agreed
with EPA’s view that State’s RACM
analysis must address those measures
that a State declines to adopt and must
show whether the combined measures
would cumulatively advance the
attainment date by at least 1 year. One
commenter questioned the legal basis
for EPA’s determination that the only
controls necessary to attain the PM
2.5
NAAQS as expeditiously as practicable
are those that would cumulatively
advance an area’s projected attainment
date by at least one calendar year. The
commenter suggested that control
measures that would advance
attainment by a smaller increment
‘‘would meet the criteria endorsed in
Sierra Club [Sierra Club v. EPA, 294
F.3d 155 (D.C. Cir 2002)] by
‘expedit[ing] attainment in the relevant
area.’ ’’
Response:
The EPA has consistently
interpreted RACM as a collection of
measures that would advance the
attainment date by at least 1 year, and
the courts have determined that the
statutory RACM requirement is
ambiguous and deferred to EPA’s
interpretation of the requirement. See
Sierra Club
v.
EPA
, 314 F.3d 735, 744
(5th Cir. 2002); see also
Sierra Club
v.
EPA
, 294 F.3d, 155 162 (D.C. Cir. 2002).
Contrary to the commenter’s suggestion,
the court in
Sierra Club
v.
EPA
, did not
endorse specific criteria for identifying
control measures that expedite
attainment, but instead deferred to
EPA’s interpretation of an ambiguous
statutory term. The courts deferred to
EPA’s interpretation after reviewing
EPA’s approval of State SIP
submissions. The EPA conducts such
reviews consistent with its
determination that the CAA only
requires such RACM as will provide for
attainment as expeditiously as
practicable, and its belief that it would
be unreasonable to require
implementation of measures that would
not in fact advance attainment. See 57
FR 13498, 13560 (April 15, 1992); see
also 44 FR 20372, 20374 (April 4, 1979).
In considering whether a collection of
measures would advance the attainment
date of an area, EPA has previously
interpreted the phrase ‘‘advance the
attainment date’’ as meaning that the
attainment date would be advanced by
at least 1 year. See e.g., 66 FR 57160,
57182 (Nov. 14, 2001) (approval of
Houston SIP); 66 FR 586 (Jan 3. 2001)
(approval of DC area SIP). Further,
EPA’s use of a one-year increment in
determining whether a collection of
measures would advance the attainment
date is reasonable and consistent with
the fact that all areas will be designing
attainment demonstrations for the
annual PM
2.5
standard. Section
172(a)(2)(C) statute uses 1 year as the
increment by which attainment date
extensions can be granted. Thus,
requiring evaluation of whether control
measures would advance attainment by
an increment of 1 year is a reasonable
approach for the PM
2.5
NAAQS.
Comment:
Some commenters
recommended that EPA consider not
requiring a RACM analysis for areas
projected to attain the standards within
5 years of designation, i.e., by April
2010 for the areas currently designated
nonattainment. One commenter
suggested that practical considerations
would make it impossible for any State
projected to attain by 2010 to advance
the attainment date by a year. This
commenter noted that because measures
to provide for attainment by 2010 must
be implemented by the beginning of
2009, and SIPs are not submitted until
April 2008, it would impossible to
advance the implementation of
measures by 1 year (that is, the
beginning of 2008).
Response:
The EPA generally agrees
that given the time constraints it will be
difficult for States with areas currently
designated nonattainment to devise,
adopt, and implement RACM measures
to advance the attainment date before
2010. At the same time, however, we
note that nothing precludes States from
taking early action and we encourage
States to take actions to reduce PM
2.5
concentrations where feasible even
before the SIPs are submitted. RACM is
required by the CAA and thus EPA
cannot waive the requirement for the
analysis. At the same time, EPA
recognizes that a streamlined analysis
may be appropriate given the short time
periods involved.
3. Observations and Considerations in
Determining RACT and RACM
a. Background
The preamble to the proposed rule
included a discussion of general
considerations for RACT (70 FR 66020
and 66021, latter part of section III.I.6)
and RACM (70 FR 66028, section
III.1.15). The preamble to the final rule
retains this discussion with some
modifications and restructuring to
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reflect the combined approach to RACT
and RACM
b. Final Rule
General considerations.
Once the
State has identified measures and
technologies that are available for
implementation in the nonattainment
area, then it must evaluate those
measures to determine whether
implementation of such measures are
reasonable, and would collectively
advance attainment. Many of the factors
that the State should take into
consideration in determining whether a
measure is ‘‘reasonable’’ are related to
the measure’s technical and economic
feasibility. Since RACM applies to area
and mobile sources as well as stationary
sources, the State should consider other
factors as well in conducting its RACM
analysis. For example, in many cases
obtaining emissions reductions from
area and mobile sources is achieved not
by adding control technology to a
specific emissions source, but by
reducing the level of activity of a fleet
of vehicles or by modifying a type of
commercial process. In these situations,
the State should also consider local
circumstances such as infrastructure,
population, or workforce and the time
needed to implement the measure in
light of the attainment date.
The EPA believes that while areas
projected to attain within 5 years of
designation as a result of existing
national measures should still be
required to conduct a RACT and RACM
analysis, such areas may be able to
conduct a limited RACT and RACM
analysis that does not involve additional
air quality modeling. A limited analysis
of this type could involve the review of
available reasonable measures, the
estimation of potential emissions
reductions, and the evaluation of the
time needed to implement these
measures. If the State could not achieve
significant emissions reductions by the
beginning of 2008 due to time needed to
implement reasonable measures or other
factors, then it could be concluded that
reasonably available local measures
would not advance the attainment date.
In lieu of conducting air quality
modeling to assess the impact of
potential RACT and RACM measures,
existing modeling information could be
considered in determining the
magnitude of emissions reductions that
could significantly affect air quality and
potentially result in earlier attainment.
If the State, in consultation with EPA,
determines from this initial, more
limited RACT and RACM analysis that
the area may be able to advance its
attainment date through implementation
of reasonable measures, then the State
would conduct a more detailed RACT
and RACM analysis.
Observations on control
opportunities. The implementation of
the PM
2.5
NAAQS is in its initial stages,
and many of the designated PM
2.5
nonattainment areas are not current or
former PM
10
nonattainment areas. Thus,
some existing stationary sources in
these areas may currently be
uncontrolled or undercontrolled for
PM
2.5
or PM
2.5
precursors. Further, to
this point in time, emissions controls for
existing sources in these areas may have
focused primarily on particulate matter
that is filterable at stack temperatures
and thus may not adequately control
condensable emissions. In addition,
States should bear in mind that the
controlled sources may have installed
emission controls 15 years ago or more,
and there may now be cost-effective
opportunities available to reduce
emissions further through more
comprehensive and improved emissions
control technologies, or through
production process changes that are
inherently lower in emissions.
Moreover, improved monitoring
methods may enhance the ability of
sources to maintain the effectiveness of
installed emissions controls and to
reduce emissions by detecting
equipment failures more quickly. For
example, State imposition of
requirements for more frequent
monitoring (e.g., continuous opacity
monitors, PM continuous emissions
monitors, etc.) may provide greater
assurance of source compliance and
quicker correction of inadvertent upset
emissions conditions than existing
approaches.
Even in former or current PM
10
nonattainment areas, existing
requirements for controlling direct PM
emissions (e.g., with a baghouse or
electrostatic precipitator) may not have
been revised significantly since the
1970’s. When EPA established the PM
10
standards in 1987, we stated in the
preamble that it was reasonable to
assume that control technology that
represented RACT and RACM for total
suspended particulates (TSP) should
satisfy the requirement for RACT and
RACM for PM
10
. 52 FR 24672 (July 1,
1987). The basis for EPA’s belief was
that controls for PM
10
and TSP would
both focus on reducing coarse
particulate matter, and specifically that
fraction of particulate matter that is
solid (rather than gaseous or
condensable) at typical stack
temperatures. However, emission
controls to capture coarse particles in
some cases may be less effective in
controlling PM
2.5
. For this reason, there
may be significant opportunities for
sources to upgrade existing control
technologies
28
and compliance
monitoring methods to address direct
PM emissions contributing to fine
particulate matter levels with
technologies that have advanced
significantly over the past 15 years.
Precursor Controls.
It will be
important for States to conduct RACT
and RACM determinations for stationary
sources of PM
2.5
precursors as well as
direct PM
2.5
emissions although, as
noted above, the known atmospheric
chemistry of the area may dictate the
necessary rigor of this analysis. A
significant fraction of PM
2.5
mass in
most areas violating the standards is
attributed to secondarily-formed
components such as sulfate, nitrate, and
some organic PM, and EPA believes that
certain stationary sources of precursors
of these components in nonattainment
areas currently may be poorly
controlled. Accordingly, to address
these precursors, States should review
existing sources for emission controls or
process changes that could be
reasonably implemented to reduce
emissions from activities such as fuel
combustion, industrial processes, and
solvent usage.
Multi-State Nonattainment Areas
.
States in multi-State nonattainment
areas will need to consult with each
other on appropriate level of RACT and
RACM for that area. We anticipate that
States may decide upon RACT and
RACM controls that differ from State to
State, based upon the State’s
determination of the most effective
strategies given the relevant mixture of
sources and potential controls in the
relevant nonattainment areas. So long as
each State can adequately demonstrate
that its chosen RACT and RACM
approach will provide for meeting RFP
requirements and for attainment of the
NAAQS as expeditiously as practicable
for the nonattainment area at issue, we
anticipate approving plans that may
elect to control a somewhat different
mix of sources or to implement
somewhat different controls as RACT
and RACM. Nevertheless, States should
consider RACT and RACM measures
developed for other areas or other
States. EPA may consider such
measures in assessing the approvability
of a State’s SIP.
c. Comments and Responses
Comment:
In the proposed rule, EPA
indicated that States could consider the
‘‘social acceptability’’ of measures as a
28
For example, see past EPA guidance on PM
2.5
control technologies: Stationary Source Control
Techniques Document for Fine Particulate Matter
(EPA–452/R–97–001), EPA Office of Air Quality
Planning and Standards, October 1998.
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factor in the determination of what
constitutes RACM in a given area. A
number of commenters recommended
that EPA eliminate use of this factor.
Some commenters questioned whether
States or EPA had the legal authority to
exclude measures from consideration
based on social acceptability or
popularity, if the measures are
technically and economically available,
and are needed to attain the NAAQS for
protection of public health. Others
expressed concerns that inclusion of
such a factor would inevitably result in
the elimination of controls for area and
mobile sources and for this reason
would unfairly focus emissions
reduction strategies on industrial
sources of PM
2.5
and precursors.
Response:
The EPA believes that in
developing RACM measures, it is
important that States not rely unduly on
measures that would be very difficult to
enforce in practice. We discourage
States from relying on measures that on
paper may seem reasonably available
but in practice might fail to achieve
benefits due to the problems and costs
of effectively enforcing these measures.
However, we recognize that the CAA
does not identify ‘‘social acceptability’’
as a factor in the definition of what may
constitute RACT or RACM, and more
generally the CAA does not establish a
preference for measures that affect
industrial sources instead of the general
public and are therefore more likely to
be ‘‘socially acceptable.’’ Therefore,
given the concerns raised by
commenters that establishment of
‘‘social acceptability’’ as a factor in the
RACM analysis is without basis in the
CAA and might result in inappropriate
skewing of control strategies, we have
removed this term from the final rule.
We reiterate, however, that capability of
effective implementation and
enforcement are relevant considerations
in the RACM analysis, even though
public ‘‘unpopularity’’ is not. Moreover,
in assessing the efficacy of measures
and the credit they should be given in
the context of attainment
demonstrations or RFP calculations,
EPA believes that such considerations
are important.
4. What Factors Should States Consider
in Determining Whether an Available
Control Technology or Measure Is
Technically Feasible?
a. Background
The following provides guidance for
States to consider in determining
whether an available control technology
is technologically feasible.
b. Final Rule
The technological feasibility of
applying an emission reduction method
to a particular source should consider
factors such as the source’s process and
operating procedures, raw materials,
physical plant layout, and any other
environmental impacts such as water
pollution, waste disposal, and energy
requirements. For example, the process,
operating procedures, and raw materials
used by a source can affect the
feasibility of implementing process
changes that reduce emissions and the
selection of add-on emission control
equipment. The operation and longevity
of control equipment can be
significantly influenced by the raw
materials used and the process to which
it is applied. The feasibility of
modifying processes or applying control
equipment also can be influenced by the
physical layout of the particular plant.
The space available in which to
implement such changes may limit the
choices and will also affect the costs of
control.
Reducing air emissions may not
justify adversely affecting other
resources by increasing pollution in
bodies of water, creating additional
solid waste disposal problems or
creating excessive energy demands. An
otherwise available control technology
may not be reasonable if these other
environmental impacts cannot
reasonably be mitigated. For analytic
purposes, a State may consider a PM
2.5
control measure technologically
infeasible if, considering the availability
(and cost) of mitigating adverse impacts
of that control on other pollution media,
the control would not, in the State’s
reasoned judgment, provide a net
benefit to public health and the
environment. However, in many past
situations, States and owners of existing
sources have adopted PM
2.5
control
technologies with known energy
penalties and some adverse effects on
other media, based on the reasoned
judgment that installation of such
technology would result in a net benefit
to public health and the environment.
States should consider this in
determining technical feasibility. The
costs of preventing adverse water, solid
waste and energy impacts should be
included in assessing the economic
feasibility of the PM
2.5
control
technology.
One particular cross-media issue
relates to concentrated animal feeding
operations (CAFOs). Should a State
determine that reductions of direct
PM
2.5
or PM
2.5
precursors from CAFOs
are necessary for attainment in a
nonattainment area, EPA strongly
suggests that the State address these
reductions from a cross-media
perspective. Since 2003, EPA and many
stakeholders have been interested in
developing a framework to enable
CAFOs to pursue superior
environmental performance across all
media. We are aware that today some
CAFOs voluntarily conduct whole-farm
audits to evaluate releases of pollutants
to all media through Environmental
Management Systems, self-assessment
tools, performance track, ISO 14001
certification, and State-approved trade
offs in meeting regulatory thresholds
between air and water that accomplish
the best overall level of environmental
protection given State and local
conditions. The EPA continues to
believe the development of new and
emerging technologies offers the
potential to achieve equivalent or
greater pollutant reductions than
achieved solely by effluent guidelines
and standards. Many of these are
superior from a multimedia perspective,
and EPA would like to encourage
superior multimedia solutions. SIPs
which need to address ammonia may
provide a unique opportunity to
encourage multimedia approaches at
CAFOs. For example, the addition of
animal by-products provides a valuable
source of nutrients for crops, improves
soil structure which enhances soil
permeability, and adds valuable organic
matter that improves soil health.
However, inappropriate application can
lead to air and water quality concerns or
the improvement of one media at the
cost of another. Optimal application
technologies and rates reduce potential
air and water quality standards
violations. The EPA does not want to
discourage approaches that are superior
from a cross media perspective.
The EPA recommends that States
evaluate alternative approaches to
reducing emissions of particulate matter
by reviewing existing EPA guidance
29
and other sources of control technology
information. The EPA’s 1998 guidance
presents information on topics such as
the design, operation and maintenance
of general particulate matter control
systems such as electrostatic
precipitators, fabric filters, and wet
scrubbers. The filterable particulate
matter collection efficiency of each
system is discussed as a function of
particle size. The guidance document
also provides information concerning
29
Stationary Source Control Techniques
Document for Fine Particulate Matter (EPA–452/R–
97–001), EPA Office of Air Quality Planning and
Standards, October 1998. See also: Controlling SO
2
Emissions: A Review of Technologies (EPA/600/R–
00/093), EPA Office of Research and Development,
November 2000.
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other relevant considerations such as
energy and environmental
considerations, procedures for
estimating costs of particulate matter
control equipment, and evaluation of
secondary environmental impacts.
Because control technologies and
monitoring approaches are constantly
being improved, the State should also
consider more updated or advanced
technologies not referenced in this 1998
guidance when conducting a RACT
determination. Emissions reductions
may also be achieved through the
application of monitoring and
maintenance programs that use critical
process and control parameters to verify
that emission controls are operated and
maintained so that they more
continuously achieve the level of
control that they were designed to
achieve.
30
c. Comments and Responses
Comment:
One commenter noted that
the guidance for ‘‘technical feasibility’’
implies that States look at individual
sources with a BACT-like case-by-case
analysis. The commenter recommended
that source owners conduct such a site-
specific analysis and submit the
analysis to the State through the
permitting process.
Response:
While the analytical
analysis to identify RACT is similar to
BACT, as noted above, EPA in the past
has issued CTGs that describe the
presumptive norm for RACT controls for
a given industry, but that allow for case-
by-case considerations for a given
source. Where States wished to require
source owners to conduct such a site-
specific analysis as part of the control
technology review, EPA supports this
type of process. On the other hand, EPA
does not believe it would be appropriate
to require all RACT-eligible sources to
conduct such an analysis, given that
States have the primary responsibility
for identifying and analyzing measures
for such sources.
5. What Factors Should States Consider
in Determining Whether an Available
Control Technology or Measure Is
Economically Feasible?
a. Background
The follow provides guidance for
States to consider in determining
whether an available control technology
is economically feasible for purposes of
identifying reasonably available control
measures. This guidance is slightly
modified from our proposal.
30
See EPA’s Web site for more information:
http://www.epa.gov/ttn/emc/monitor.html.
b. Final Rule
Economic feasibility encompasses
considerations such as whether the cost
of a potential measure is reasonable
considering attainment needs of the area
and the costs of other measures, and
whether the cost of a measure is
reasonable for the regulated entity to
bear, in light of benefits.
While many States generally establish
RACT requirements for a category of
sources, the Act does not require the
same level of control on all sources in
a category, nor does the Act require that
each source be controlled individually.
Similar sources may have different
marginal costs, profit margins and
abilities to pass costs through to the
consumer. These factors are appropriate
to consider in determining whether a
given level of control is appropriate for
an individual source or category of
sources. Accordingly, there is no
presumption that a given source must
bear a cost similar to any other source.
States should consider the capital
costs, annualized costs, cost
effectiveness of an emissions reduction
technology, and effects on the local
economy in determining whether a
potential control measure is reasonable
for an area or State. One available
reference for calculating costs is the
EPA Air Pollution Control Cost
Manual,
31
which describes the
procedures EPA uses for determining
these costs for stationary sources. The
above costs should be determined for all
technologically feasible emission
reduction options if such measure is
inherently ‘‘reasonably available’’ (e.g.,
not absurd or clearly impractical). States
may give substantial weight to cost
effectiveness in evaluating the economic
feasibility of an emission reduction
technology. The cost effectiveness of a
technology is its annualized cost ($/
year) divided by the emissions reduced
(i.e., tons/year) which yields a cost per
amount of emission reduction ($/ton).
Cost effectiveness provides a value for
each emission reduction option that is
comparable with other options and
other facilities. Where multiple control
options exist for a given source or
source category, States should consider
both the cost effectiveness (dollars per
ton) of each option, and the incremental
cost effectiveness per ton between the
options (incremental increase in cost
between options divided by the
incremental tons reduced).
In determining whether a given
measure is reasonable, States may
31
EPA Air Pollution Control Cost Manual—Sixth
Edition
(EPA 452/B–02–001), EPA Office of Air
Quality Planning and Standards, Research Triangle
Park, NC, Jan 2002.
consider costs per ton of other measures
previously employed to reduce that
pollutant, but similar costs are not
conclusive. As discussed above, States
may evaluate equity considerations in
weighing the economic feasibility of
imposing a measure on a given source
or source category.
We anticipate that States may decide
upon RACT and RACM controls that
differ from State to State, based on the
State’s determination of the most
effective strategies given the relevant
mixture of sources and potential
controls in the relevant nonattainment
areas, and differences in the difficulty of
reaching attainment.
In considering what level of control is
reasonable, EPA is not proposing a fixed
dollar per ton cost threshold for RACT,
consistent with the views of multiple
commenters. Areas with more serious
air quality problems typically will need
to obtain greater levels of emissions
reductions from local sources than areas
with less serious problems. Where
essential reductions are more difficult to
achieve (e.g., because many sources are
already controlled), the cost per ton of
control may necessarily be higher.
It is not appropriate to assume that
the same cost per ton range is
reasonable for direct PM
2.5
and different
precursors, because an equal amount of
emission reduction in different
pollutants has a different impact on
PM
2.5
ambient levels. For example, in a
given nonattainment area, reductions of
direct PM
2.5
emissions may prove more
expensive than reductions of NO
X
emissions, but the resulting benefits of
reductions of direct PM
2.5
might warrant
the higher costs. A State should
consider this differential impact on
ambient PM
2.5
in considering RACT for
controlling different pollutants. During
the SIP process, States and regional
planning organizations typically
conduct sensitivity modeling that can
provide this information. Also, the PM
NAAQS RIA provides information on
the differential impact of PM
2.5
and PM
precursor reductions on ambient PM
2.5
levels in various areas.
32
One of the factors that could affect
estimated compliance costs of an
emission reduction measure is the
timing of its implementation.
Hypothetically, if a short compliance
period were contemplated for a set of
sources, and if the short compliance
32
See: U.S. EPA 2006.
Regulatory Impact
Analysis for the Particulate Matter National
Ambient Air Quality Standards.
Air Benefits and
Cost Group, Office of Air Quality Planning and
Standards, Research Triangle Park, NC, October 6,
2006. Appendix A provides an analysis of estimated
benefits and costs of attaining the 1997 PM NAAQS
standards in 2015.
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period resulted in high demand for a
limited supply of labor or other
resources, compliance costs could be
higher than if the same measure were
implemented by a later compliance
date. In such a case it may be reasonable
for the State to find that the measure is
reasonable only if implemented by the
later date.
If a source contends that a source-
specific RACT level should be
established because it cannot afford the
technology that appears to be RACT for
other sources in its source category, the
source can support its claim with such
information as:
—Fixed and variable production costs
($/unit)
—Product supply and demand
elasticity,
—Product prices (cost absorption vs.
cost pass-through),
—Expected costs incurred by
competitors,
—Company profits once the technology
or measure is in operation
(considering the annualized costs and
the marginal costs of alternative
technologies and measures),
—Employment costs, and
—Any other unique factor(s) particular
to the individual source.
Finally, the EPA clarifies that if the
State demonstrates through economic
analysis that the imposition of the
measure would cause unacceptable
economic disruption for the local
economy, that is, a plant shutdown or
a severe curtailment in plant
employment or output, a State may
reject the measure as not reasonable to
reach attainment as expeditiously as
practicable.
c. Comments and Responses
Comment:
Some commenters agreed
with EPA’s proposal not to establish
presumptive cost-effectiveness
thresholds.
Response:
The EPA agrees with the
commenters.
Comment:
A number of commenters
expressed concerns over the references
to health benefits as a consideration in
whether measures are technically or
economically available. Some
commenters believed this is a
consideration not authorized by the
CAA. Others believed that consideration
of benefits, in combination with EPA’s
estimates of benefits per ton, would
have the effect of converting RACT to
more stringent LAER levels. Some
commenters expressed concerns
whether States had the resources or
expertise to conduct cost-benefit
analyses for this purpose.
Response:
The EPA wishes to clarify
that the reference to health benefits does
not mean that a cost-benefit, or a
detailed health benefits assessment, is a
necessary part of a control strategy
demonstration. We also wish to clarify
that EPA is not requiring that the costs
of all technologies and measures for
PM
2.5
and precursors be deemed
acceptable at any dollar/ton levels at or
below the calculated monetized benefits
per ton of reduction. We do, however,
continue to believe that the significant
benefits associated with PM
2.5
ambient
reductions is a relevant consideration in
control strategy development. The EPA
disagrees that this limited consideration
of benefits would convert the RACT
process to the equivalent of LAER.
Comment:
One commenter objected to
EPA’s proposed requirement that States
consider competitive factors such as
production costs, demand elasticity,
product prices, and cost incurred by
competitors in the determination of
RACT. The commenter believed that
this information is generally not
accessible to States or industrial facility
owners, and is not necessary for a RACT
determination.
Response:
The EPA generally
disagrees that this type of information is
unavailable. For example, EPA
calculates or reviews this type of data
on a regular basis as part of our work on
MACT, NSPS, and other emissions
standards. A document that describes
these types of analyses and the data
used to prepare them is the OAQPS
Economic Resource Manual found at
http://www.epa.gov/ttn/ecas/
analguid.html.
EPA believes that this
issue is most relevant to category-wide
RACT rules where a source seeks a case-
by-case exemption. Further, EPA
believes most RACT determinations will
be developed through case-by-case
analyses rather than rules affecting
entire source categories. Accordingly,
this analysis likely will be relevant in
few cases.
6. What Specific Source Categories and
Control Measures Should a State
Evaluate When Determining RACT and
RACM for a Nonattainment Area?
a. Background
Section 172 does not provide a
specific list of source categories and
control measures that must be evaluated
for RACT and RACM for PM
2.5
.
However, section 172(c)(3) indicates
that the attainment plan must include a
‘‘comprehensive, accurate, current,
inventory of actual emissions from all
sources of the relevant pollutant.’’ This
indicates that States should look
broadly at the different types of sources
in the nonattainment area. We recognize
that PM
2.5
is a new NAAQS without a
long history of implementation as with
ozone. Therefore, we included a list of
potential RACM measures in the
preamble to the proposed rule, based
upon a review of information about the
contribution of various sources to
emissions inventories and a review of
potential control measures for such
sources. We requested comment on the
specific sources and potential control
measures recommended for RACM
analysis on this list. Based on comments
received and additional information
available to EPA since the proposal, we
have made some changes to the list. We
also refer to this list of potential ‘‘RACT
and RACM’’ measures for the combined
approach to RACT and RACM in the
final rule.
In the preamble to the proposed rule,
EPA indicated that due to the short time
available, it does not plan to develop
new control techniques guidance (CTG)
or ACT documents specifically for
purposes of PM
2.5
implementation. The
EPA indicated that other information
was available on control technologies,
and EPA also indicated its intention to
maintain an updated list of references
for new PM
2.5
control technology
information.
b. Final Rule
Emission reduction measures
constituting RACM should be
determined on an area-by-area basis. We
believe that a State should consider
each of the measures listed in this
section to determine if each measure is
reasonably available in the applicable
nonattainment area. However, we do not
presume that each of these measures is
reasonably available in each
nonattainment area.
We recommend that each State use
the list of source categories in this
section as a starting point for identifying
potentially available control strategies
(regulatory and voluntary) for a
nonattainment area. States are
encouraged and expected to add other
potentially available measures to the list
based on its knowledge of the particular
universe of emissions sources in the
area and comments from the general
public. We expect that, depending on
the potential measure being analyzed,
the State’s degree of evaluation will vary
as appropriate. Detailed information on
emission control technologies is
available from a number of sources.
33
The EPA intends to maintain a website
with links to sources of information for
33
There are a number of sources of information
on technologies for reducing emissions of PM
2.5
and
its precursors. Links are provided to a number of
national, state and local air quality agency sites
from EPA’s PM
2.5
Web site:
http://www.epa.gov/
pm/measures.html.
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controlling emissions of direct
particulate matter and PM precursors.
As discussed in section II.J.5. above,
EPA recognizes that control technology
guidance for certain source categories
has not been updated for many years.
Section 183(c) of the CAA, which
addresses control technologies to
address ozone nonattainment problems,
requires EPA to ‘‘revise and update such
documents as the Administrator
determines necessary.’’ As new or
updated information becomes available
States should consider the new
information in their RACT
determinations. A State should consider
the new information in any RACT
determinations or certifications that
have not been issued by the State as of
the time such updated information
becomes available.
Stationary Source Measures
—Stationary diesel engine retrofit,
rebuild or replacement, with
catalyzed particle filter
—New or upgraded emission control
requirements for direct PM
2.5
emissions at stationary sources (e.g.,
installation or improved performance
of control devices such as a baghouse
or electrostatic precipitator; revised
opacity standard; improved
compliance monitoring methods)
—Improved capture of particulate
emissions to increase the amount of
PM
2.5
ducted to control devices, and
to minimize the amount of PM
2.5
emitted to the atmosphere, for
example, through roof monitors
—New or upgraded emission controls
for PM
2.5
precursors at stationary
sources (e.g., SO
2
controls such as wet
or dry scrubbers, or reduced sulfur
content in fuel; desulfurization of
coke oven gas at coke ovens;
improved sulfur recovery at refineries;
increasing the recovery efficiency at
sulfuric acid plants)
—Energy efficiency measures to reduce
fuel consumption and associated
pollutant emissions (either from local
sources or distant power providers)
—Measures to reduce fugitive dust from
industrial sites
Mobile Source Measures
—Onroad diesel engine retrofits for
school buses,
34
trucks and transit
buses using EPA-verified technologies
34
See Clean School Bus USA program at
http://
www.epa.gov/cleanschoolbus/.
See also: ‘‘What You
Should Know About Diesel Exhaust and School Bus
Idling,’’ (June 2003, EPA420–F–03–021) at
http://
www.epa.gov/otaq/retrofit/documents/f03021.pdf.
—Nonroad diesel engine retrofit, rebuild
or replacement, with catalyzed
particle filter
35
—Diesel idling programs for trucks,
locomotive, and other mobile
sources
36
—Transportation control measures
(including those listed in section
108(f) of the CAA as well as other
TCMs), as well as other transportation
demand management and
transportation systems management
strategies
37
—Programs to reduce emissions or
accelerate retirement of high emitting
vehicles, boats, and lawn and garden
equipment
—Emissions testing and repair/
maintenance programs for onroad
vehicles
—Emissions testing and repair/
maintenance programs for nonroad
heavy-duty vehicles and equipment
38
—Programs to expand use of clean
burning fuels
39
—Low emissions specifications for
equipment or fuel used for large
construction contracts, industrial
facilities, ship yards, airports, and
public or private vehicle fleets
—Opacity or other emissions standards
for ‘‘gross-emitting’’ diesel equipment
or vessels
Area Source Measures
—New open burning regulations and/or
measures to improve program
effectiveness such as programs to
reduce or eliminate burning of land
clearing vegetation
—Programs to reduce emissions from
woodstoves and fireplaces including
outreach programs, curtailments
during days with expected high
ambient levels of PM
2.5
, and programs
to encourage replacement of
woodstoves when houses are sold
—Controls on emissions from
charbroiling or other commercial
cooking operations
—Reduced solvent usage or solvent
substitution (particularly for organic
compounds with 7 carbon atoms or
more, such as toluene, xylene, and
trimethyl benzene)
35
See EPA’s voluntary diesel retrofit program
Web site at
http://www.epa.gov/otaq/retrofit/
overfleetowner.htm.
36
See EPA’s voluntary diesel retrofit program
Web site at
http://www.epa.gov/otaq/retrofit/
idling.htm.
37
See EPA’s Web site on transportation control
measures at
http://www.epa.gov/otaq/transp/
traqtcms.htm.
38
See EPA’s Web site on nonroad engines,
equipment, and vehicles at
http://www.epa.gov/
otaq/nonroad.htm.
39
Fuels adopted in SIPs must be consistent with
the Energy Policy Act of 2005 and EPA guidance
on SIP-approved boutique fuels at 71 FR 78192
(December 28, 2006).
Category-Specific Guidelines on
innovative approaches.
The EPA has
issued a number of category specific
guidelines on approaches to taking into
account innovative approaches to
emissions reductions for purposes of
SIPs. Categories currently covered by
these guidelines include: (1) Electric-
sector Energy Efficiency and Renewable
Energy Measures; (2) Long Duration
Switch Yard Locomotive Idling; (3)
Long Duration Truck Idling; (4) Clean
Diesel Combustion Technology; and (5)
Commuter Choice Programs. See
http://
www.epa.gov/ttn/airinnovations/
measure
_
specific.html.
c. Comments and Responses
Comment:
Some commenters
recommended that EPA provide new
CTGs or other control technology review
documents for purposes of assisting
States to address PM
2.5
and its
precursors, because the information in
some current documents is out-dated.
Response:
The EPA recognizes that
issuance of new or updated CTGs
specifically tailored for PM
2.5
would be
useful. Unfortunately, limitations on
time and resources preclude EPA from
developing such CTGs in advance of the
SIP submission date. The EPA cannot
delay the statutorily specified outer date
for SIP submission. However, EPA
believes that there are already many
sources of information and guidance on
key source categories. To the extent that
States need to examine potential control
measures for sources never addressed
before in any area or other context for
a previous NAAQS, EPA anticipates that
it will work closely with States during
the process of plan development and
approval to ensure an appropriate
approach.
Comment:
A number of commenters
expressed concerns with references to
the STAPPA and ALAPCO
Menu of
Options
document. Some commenters
believed that this document must be
subject to formal review and comment
to ensure appropriate stakeholder input.
Response:
The language in the final
preamble has been changed to refer to
a Web site EPA maintains that provides
access to a variety of information
sources regarding control technologies
that may be useful to States to consider
in developing their PM
2.5
SIPs. These
links include evaluations developed by
government and nongovernment
organizations. One such source with
potentially useful information is the
STAPPA and ALAPCO
Menu of
Options.
However, EPA is not
specifically endorsing any of the
specific evaluations as being
appropriate in any specific situation.
Rather, we think documents such as the
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Menu of Options
provide potentially
useful ideas. Specifically, States would
need to assess which items on the menu
are applicable in their areas, and will
have to assess the costs of applying
controls locally. Accordingly, there
would be ample opportunity for public
review of the State’s analysis of the local
cost and air quality impacts of any
measure listed in the document which
is included in a State’s SIP. The EPA is
not requiring that States adhere to the
list of measures in the
Menu of Options.
The EPA does not in any way mean to
imply that the measures in the
Menu of
Options
are presumed to be RACM,
merely that they are potential controls
for areas to consider. The
Menu of
Options
has no regulatory significance
and thus need not be issued through
notice-and-comment rulemaking. The
EPA notes, however, that the
Menu of
Options
does provide a broad list of
potential sources and measures that can
help inform States in the development
of their plans. Similarly, our own list of
potential measures is not intended to be
a categorical list of measures which
States must adopt, rather it is intended
to provide guidance about the types of
sources and measures that States can
consider in constructing their
attainment plans. The EPA emphasizes
that whether a source category or
potential measure is or is not on this list
is simply not conclusive as to whether
a given measure is appropriate to
consider in the RACT and RACM
analysis. That can be determined only
through the State’s development of the
attainment plan, and EPA’s evaluation
of such plan.
Comment:
A commenter representing
the paper industry interpreted the
proposed rule as requiring electrostatic
precipitator and tighter sulfur-in-fuel
requirements for the forest products
industry. The commenter believed that
EPA was creating limits for such sources
without adequate rulemaking process.
Response:
The EPA disagrees that the
listing of control technologies in the
table in the rule creates a ‘‘rebuttable
presumption.’’ Rather, the table
identifies potential opportunities for
emissions reductions which should be
reviewed in light of technical and
economic feasibility, and which a State
should consider in a list of possible
RACT and RACM measures for purposes
of attaining the standards as
expeditiously as practicable. The EPA is
currently conducting a sector-based
approach to the paper industry. One of
the goals of the sector initiative on pulp
and paper is to work with the industry
to identify reductions in SO
2
and PM
2.5
that will assist us in meeting the
NAAQS, considering facility locations,
magnitude of emissions, emission
stream characteristics, and cost
effectiveness of controls.
Comment:
A number of commenters
believed that EPA should develop not
only a list of measures to consider for
RACM, but should develop a list of
mandatory measures that States should
include, particularly for areas with
attainment dates more than 5 years after
designation.
Response:
See discussion in section
II.D.3 regarding rule requirements for
attainment date extensions and the issue
of whether certain measures should be
mandatory in order for an area to
receive an extension.
Comment:
Some commenters believed
that the list of possible measures was
deficient in not including sources of
PM
2.5
and PM
2.5
precursors from
agricultural sources. One commenter
believed the list is incomplete without
identifying the contribution of ammonia
emissions associated with livestock,
poultry, and crop fertilizers.
Response:
As we indicated in the
proposal, we included a list of potential
RACM measures in the preamble to the
proposed rule, based upon a review of
information about the contribution of
various sources to the emissions
inventories and a review of potential
control measures for such sources. We
did not identify emissions from
agricultural sources in this review.
Because ammonia is not presumed to be
a PM
2.5
precursor unless identified for a
specific area by the State or EPA,
regulation of ammonia emissions from
agricultural sources may not be
necessary.
We also note that the agricultural
industry presents unique challenges to
regulators given the nature of relevant
emissions sources. Moreover, we
currently lack good methods to quantify
agricultural emissions, and we do not
fully understand their contribution to
nonattainment problems. We have
entered into an agreement with several
animal producer sectors to monitor
animal feeding operations to develop
better tools to assess emissions from this
industry. Hopefully, these tools will
enhance our knowledge of agricultural
emissions and their contribution to
nonattainment problems. Until
emissions from these sources are better
understood, States should be judicious
in determining whether any specific
measure is RACT/RACM for this
industry.
The EPA recognizes that the United
States Department of Agriculture
(USDA) has been working with the
agricultural community to develop
conservation systems and activities to
control coarse particle emissions. Based
on current ambient monitoring
information, these USDA-approved
conservation systems and activities have
proven to be effective in controlling
these emissions in areas where coarse
particles emitted from agricultural
activities have been identified as a
contributor to a violation of the PM
10
NAAQS. The EPA has found that where
USDA-approved conservation systems
and activities have been implemented,
these systems and activities have
satisfied the Agency’s reasonably
available control measure and best
available control measure requirements
for areas needing to attain the PM
10
standards.
The EPA believes that in the future,
certain USDA-approved conservation
systems and activities that reduce
agricultural emissions of fine particles
may be able to satisfy the requirements
of applicable sources to implement
reasonably available control measures
for purposes of attaining the PM
2.5
NAAQS. The EPA will work with States
to identify appropriate measures to meet
their RACM requirements, including
site-specific conservation systems and
activities. The EPA will continue to
work with USDA to prioritize the
development of new conservation
systems and activities; demonstrate and
improve, where necessary, the control
efficiencies of existing conservation
systems and activities; and ensure that
appropriate criteria are used for
identifying the most effective
application of conservation systems and
activities.
Comment:
Some commenters raised
concerns about a statement in the
proposal that ‘‘[i]n addressing a
nonattainment area having military
training, testing and operational
activities occurring within it, the State
should not need to target these activities
for emission reductions.’’ Some
commenters interpreted this statement
as an exemption from any emission
reduction requirements for military
sources.
Response:
The statement in the
proposal was not intended as an
exemption for all military activities.
Emissions potentially contributing to
PM
2.5
concentrations at military
installations originate from a variety of
sources: basic operational activities
(such as power generation, other fuel
combustion, and transportation to and
from residences, offices, and schools);
and from field training and testing
activities (such as personnel training,
obscurants used in training, operation of
nonroad vehicles and equipment, and
related prescribed burning operations).
The EPA believes that in evaluating
emissions for a specific nonattainment
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area having military activities occurring
within it, the State should consult with
DOD for information on the nature of
these activities and their associated
emissions.
With regard to military training
activities specifically, such activities are
periodic in nature, and when they do
occur, the principal type of emissions
generated by these activities is dust (i.e.
inorganic direct PM emissions) from
field operations. Other pollutants may
be emitted to a lesser degree from
certain onroad and nonroad motor
vehicles. While military training
activities may contribute some degree of
primary PM
2.5
emissions to certain
nonattainment area inventories, the
fugitive dust generated from military
training activities is predominantly
composed of coarse PM rather than fine
PM.
Based on data from the PM
2.5
speciation monitoring network operated
by EPA and the States, the contribution
of inorganic dust to total PM
2.5
mass on
an annual average basis is relatively low
in most nonattainment areas, on the
order of 0.5 to 1.5 micrograms per cubic
meter (generally 10% or less of total
PM
2.5
mass). Dust from military training
activities would be a subset of these
levels. Depending on the available
information and specific circumstances
for a particular area, a State could find
in its SIP development analyses that
direct PM
2.5
emissions from military
training activities do not significantly
contribute to PM
2.5
concentrations in the
nonattainment area, and therefore
would not need to target military
training activities for emission
reductions in its attainment plan.
40
7. How Should States Consider EGU
Reductions for CAIR in Meeting RACT/
RACM Requirements?
a. Background
In section III.I.11 of the preamble to
the proposed rule, we discussed the
nature of the SO
2
and NO
X
RACT
obligations of electric generating unit
(EGU) sources in states subject to the
CAIR emission reduction requirements.
40
Windblown dust from agricultural tilling
activities also can be a periodic source of inorganic
PM in some areas. In some cases such dust would
be expected to be predominantly composed of
coarse PM rather than fine PM. Depending on the
available information and specific circumstances
for a particular area, it is possible that a State could
find in its SIP development analyses that direct
PM
2.5
emissions from agricultural tilling activities
do not significantly contribute to annual average
PM
2.5
concentrations in the nonattainment area, and
therefore would not need to require emission
reductions from agricultural tilling activities in the
plan for attaining the annual standard. However,
States should be mindful of the contribution of
these sources to 24-hour fine particle
concentrations.
The CAIR rulemaking was finalized in
March 2005 and published at 70 FR
25221 (May 12, 2005). CAIR requires 28
states and the District of Columbia to
significantly reduce emissions of SO
2
and/or NO
X
. The 26 jurisdictions in the
CAIR PM
2.5
region are required to
reduce annual emissions of SO
2
and
NO
X
, and the 26 jurisdictions in the
CAIR ozone region are required to
reduce seasonal emissions of NO
X
.
These jurisdictions also have the option
of participating in EPA-administered
annual SO
2
, annual NO
X
, and seasonal
NO
X
cap-and-trade programs (the CAIR
trading programs) to meet these
emission reduction requirements. In
addition, in March 2006, EPA
promulgated a Federal implementation
plan (FIP) to implement CAIR in these
jurisdictions until they have EPA
approved CAIR SIPs in place (71 FR
25328, April 28, 2006). The FIP adopts,
as the control measure, the CAIR trading
programs slightly modified to allow for
Federal instead of State implementation.
When fully implemented, CAIR will
reduce SO
2
emissions in these
jurisdictions by over 70 percent and
NO
X
emissions by over 60 percent from
2003 levels. This will result in $85 to
$100 billion in health benefits and
nearly $2 billion in visibility benefits
per year by 2015 and will substantially
reduce premature mortality in the
eastern United States. The benefits will
continue to grow over time as the
program is fully implemented (i.e., the
SO
2
emission bank is depleted and the
final cap is met), and as growth in
populations and the aging of the
population continues (which increases
the susceptible population).
Sources subject to cap-and-trade
programs such as the CAIR trading
programs generally have the option of
installing emissions control technology,
adopting some other strategy to reduce
emissions, or purchasing emissions
allowances and thereby effectively
paying other sources covered by the cap
to reduce emissions. In the proposal, we
noted that a number of EGUs expected
to be covered by the CAIR trading
programs are located in nonattainment
areas. Based on emissions projections
for 2010 and 2015 using the Integrated
Planning Model (IPM), some of these
EGUs are expected to comply with CAIR
by purchasing allowances under the
trading program and some are expected
to comply by installing emission
controls.
The proposal also described our past
experience with the implementation of
the NO
X
SIP Call and our belief that
many power companies will develop
their strategies for complying with CAIR
based, in part, on consultations with
State and local air quality officials in
order to address local PM
2.5
and ozone
attainment planning needs. The EPA
suggested that consultations on location
of CAIR controls would be timely
during State development of the CAIR
SIP, which is due in 2006, prior to the
April 2008 deadline for submitting
PM
2.5
nonattainment area SIPs.
The EPA proposed a determination
that in States that fulfill their CAIR SO
2
emission reductions entirely through
EGU emission reductions (i.e. without
reductions from non-EGU sources or
allowing non-EGU sources to opt-in to
the CAIR SO
2
trading program),
participation in the CAIR SO
2
trading
program would satisfy the SO
2
RACT
requirement for the EGU sources. The
EPA also proposed that in states that
fulfill their CAIR NO
X
emission
reductions entirely through EGU
emission reductions, CAIR would
satisfy NO
X
RACT for the EGU sources,
provided that those sources with
existing selective catalytic reduction
(SCR) emission control technology
installed on their boilers operate that
technology on a year-round basis
beginning in 2009. Note that direct
PM
2.5
emissions are not addressed by
the CAIR program, and EPA did not
propose any determination that
compliance with CAIR would satisfy
RACT for direct PM
2.5
emissions. The
proposal included a discussion of the
rationale for these proposed
determinations for SO
2
and NO
X
, and
requested comments on the issue.
b. Final Rule
As discussed in section II.F.2 on our
overall policy for RACT and RACM, we
consider an area’s obligation to
implement RACT to be part of the area’s
overall RACM obligation—to adopt
those reasonably available measures
needed to reach PM
2.5
attainment as
expeditiously as practicable. The final
rule also reflects this combined RACT/
RACM approach regarding EGU control
obligations under CAIR and the extent
to which meeting CAIR also satisfies a
source’s RACT and RACM requirements
for attainment.
Specifically, the final rule includes a
presumption that in States that fulfill
their CAIR SO
2
emission reduction
requirements entirely through EGU
emission reductions (i.e. without
reductions from non-EGU sources or
allowing non-EGU sources to opt in to
the CAIR SO
2
trading program),
compliance by EGU sources with an
EPA-approved CAIR SIP or a CAIR FIP
would satisfy their SO
2
RACT/RACM
requirements for attaining the fine
particle NAAQS. This section also
includes a presumption that in States
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that are subject to CAIR annual NO
X
emission reduction requirements and
fulfill these requirements entirely
through EGU emission reductions (i.e.
without reductions from non-EGU
sources or allowing non-EGU sources to
opt in to the CAIR annual NO
X
trading
program), compliance by EGU sources
with an EPA-approved CAIR SIP or a
CAIR FIP would satisfy the NO
X
RACT/
RACM requirement for the PM
2.5
NAAQS, provided that the sources with
existing selective catalytic reduction
(SCR) emission control technology
installed on their boilers operate that
technology on a year-round basis
beginning in 2009. This final position is
based on a number of factors identified
in the proposal and discussed below.
Many PM
2.5
nonattainment areas are
projected to achieve significant SO
2
and
NO
X
reductions under the CAIR
program. We do not believe that
requiring source-specific RACT/RACM
controls on specified EGUs in
nonattainment areas would reduce total
SO
2
and NO
X
emissions from sources
covered by CAIR below the regionwide
levels that will be achieved under CAIR
alone. Nor do we believe that ‘‘beyond
CAIR’’ EGU controls for SO
2
and NO
X
are ‘‘reasonably available’’ control
measures for most areas within the
CAIR Region. Accordingly, most States
need not evaluate additional control
measures on EGUs to satisfy RACT/
RACM requirements as explained above.
As discussed previously, we are not
requiring that States impose RACT on
any specific size or type of source.
Instead, States must conduct a RACT/
RACM analysis considering measures
that are ‘‘reasonably available’’ to meet
the overarching requirement to attain
the standards as expeditiously as
practicable. Thus, the final rule imposes
no specific requirement on States to
impose RACT/RACM on EGUs.
Nonetheless, in evaluating RACT/
RACM for EGUs, EPA believes it is
appropriate for States (states that
achieve all reductions from EGUs) to
consider the special attributes of that
group of facilities including the unique
interrelated nature of the power supply
network, and their participation in the
CAIR program. For EGUs in the CAIR
region, based upon the presumption
explained here, States may define
RACT/RACM as the CAIR level of
control on the collective group of
sources in the region rather than impose
a specific level of control on an
individual source. This approach is
similar to the Agency’s past ‘‘bubble’’
policy, as discussed in section (c)
addressing comments on the proposal.
As discussed more fully in the CAIR
final rulemaking notice, EPA has set the
2009 and 2010 CAIR caps for SO
2
and
NO
X
at a level that will require EGUs to
install emission controls on the
maximum total capacity on which it is
feasible to install emission controls by
those dates. The EPA concluded that the
CAIR compliance dates represent an
aggressive schedule that reflects the
limitations of the labor pool, and
equipment/vendor availability, and
need for electrical generation reliability
for installation of emission controls.
Although the actual SO
2
cap does not
become effective until 2010, we
designed banking provisions in CAIR so
that covered EGUs will begin to reduce
their SO
2
emissions almost immediately
after CAIR is finalized, and will
continue steadily to reduce their
emissions in anticipation of the 2010
cap and the more stringent cap that
becomes effective in 2015. The 2015
SO
2
and NO
X
caps are specifically
designed to eliminate all SO
2
and NO
X
emissions from EGUs that are highly
cost effective to control (the first caps
represent an interim step toward that
end).
Moreover, we predicted that the
majority of large coal-fired utilities will
install advanced control technologies
under CAIR because the larger and
higher emitting source offer an
opportunity to obtain more cost-
effective emissions reductions. We
expect that the largest-emitting sources
will be the first to install SO
2
and NO
X
control technology and that such control
technology will gradually be installed
on progressively smaller-emitting
sources until the ultimate cap is
reached. As a result, few, if any coal-
fired units with greater than 600 MW of
operating capacity should operate in
PM
2.5
nonattainment areas without
advanced control after full
implementation of CAIR. Of the
remaining units operating without
advanced pollution controls, a great
many of these units will have operating
capacities below 300 MW. We predict
that these units ‘‘will be utilized less
often,’’ and ‘‘typically have baghouses
and electrostatic precipitators for
particulate control, have combustion
controls for NO
X
control, and burn low-
sulfur coal.’’ See ‘‘Contributions of
CAIR/CAMR/CAVR to NAAQS
Attainment: Focus on Control
Technologies and Emission Reductions
in the Electric Power Sector,’’ Office of
Air and Radiation, U.S. Environmental
Protection Agency, April 18, 2006
(available at
http://www.epa.gov/
airmarkets/cair/analyses/
naaqsattainment.pdf
). In light of these
expected results, we generally believe
that the cost to install additional
controls on these smaller units would be
unreasonable.
We are also concerned that if States
require specific EGUs to install
advanced pollution control measures, it
could interfere with the market-based
incentives inherent in the cap and trade
program. This could increase the cost of
compliance and shift the location of the
units that would otherwise opt to install
advanced emissions controls. Such a
result may be counterproductive to that
State’s attainment efforts, as the State
may forego a larger quantity of more
beneficial reductions in transported
pollutants, in exchange for a smaller
quantity and less beneficial reduction in
local emissions. Moreover, it may
reduce the benefits expected in other
nonattainment areas as well.
Accordingly, even if a State found the
cost to control an individual unit
acceptable on a cost per ton basis, the
potential overall disbenefit of control
may nonetheless make imposition of the
control not ‘‘reasonably available.’’
The EPA finds that the control
installations projected to result from
CAIR NO
X
and SO
2
caps in 2009 and
2010 are as much as feasible from EGUS
across the CAIR Region by those dates.
In fact, if states chose to require smaller-
emitting sources in nonattainment areas
to meet source-specific RACT
requirements by 2009, they would likely
use labor and other resources that
would otherwise be used for emission
controls on larger sources. Because of
economies of scale, more boiler-makers
may be required per megawatt of power
generation for smaller units than larger
units. In this case, the imposition of
source-specific RACT/RACM on smaller
emitting sources by 2009 could actually
reduce the amount of banking that
would otherwise occur and result in
higher SO
2
emissions in 2009 as
compared to the level that would result
from implementation of CAIR alone.
In any event, the imposition of
source-specific control requirements on
a limited number of sources also
covered by a cap-and-trade program
would not reduce the total regionwide
emissions from sources subject to the
program. Under a cap-and-trade
program such as CAIR, a given number
of allowances are issued in order to
achieve a given emission level. Source-
specific control requirements within the
CAIR program may affect the temporal
distribution of emissions (by reducing
banking and thus delaying early
reductions) or the spatial distribution of
emissions (by moving them around from
one place to another), but they would
not affect total regional emissions under
the program. If source-specific
requirements were targeted at the units
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that could be controlled most cost-
effectively, then the imposition of
source-specific controls would likely
achieve the same result as the cap-and-
trade program. If not, however, the
imposition of source-specific
requirements would make any given
level of emission reduction more costly
than it would be under the cap-and-
trade program alone. Thus, the
imposition of source-specific RACT on
EGUs covered by CAIR would not
reduce total regionwide emissions, but
would likely achieve emission
reductions under the program in a more
costly way.
Given the considerations described
above, we think that in many areas
additional controls on EGUs generally
would not be ‘‘reasonably available.’’
Notwithstanding these conclusions, we
recognize that States are in the best
position to determine how best to
achieve attainment with the PM
2.5
NAAQS in light of local needs and
conditions. As we acknowledged in our
proposed rule, power plant operators
typically have ongoing relationships
with the State and local officials
involved in air quality planning. We
expect that power plants will continue
to collaborate with State officials to
determine how best to address multiple
air quality goals, and which plant
locations to control under CAIR,
considering local PM
2.5
and ozone
attainment needs.
The EPA expects States and local air
agencies to identify reasonably available
control measures that are necessary and
reasonable to attain the standards as
expeditiously as practicable; and that
after consulting with power companies,
the State may conclude that establishing
additional ‘‘beyond CAIR’’ emission
control requirements on specific sources
in nonattainment areas is warranted to
provide for attainment as expeditiously
as practicable. Nevertheless, in
preparing the overall attainment
demonstration, States should be aware
of the expected benefits of the market-
based incentives of the CAIR program,
the cost effectiveness of control,
feasibility of implementation, and any
disbenefits that would result from
requiring ‘‘beyond CAIR’’ controls on
any specific EGU before concluding that
additional controls on EGUs are
‘‘reasonably available’’ and necessary to
satisfy RACT/RACM requirements.
Year-round NO
X
controls. In the CAIR
final rulemaking notice, EPA found that
the operation of existing SCRs on a year-
round basis, instead of operating them
only during the ozone season, could
achieve NO
X
reductions at low cost
relative to other available NO
X
controls.
The EPA projected that power
generators would employ this control
measure to comply with CAIR SIPs.
Based on this control opportunity, EPA
estimated the average cost of non-ozone-
season NO
X
control at $500/ton. These
considerations support a finding that
RACT should include year-round
operation of existing SCRs that are
located in PM
2.5
nonattainment areas.
Because all PM
2.5
nonattainment areas
violate the annual form of the PM
2.5
standard and public health can be
affected by high PM
2.5
levels in the
winter as well as the summer, we
believe that year-round operation of
existing SCR that are located in
nonattainment areas where NO
X
is an
attainment plan precursor will provide
additional health benefits for relatively
low dollar cost per ton of pollutant
reduced.
In the proposal notice, EPA proposed
to define ‘‘existing’’ SCRs as those units
that were in place by the date of the
proposed rule (November 1, 2005). We
selected this date rather than the final
date to avoid creating an incentive to
delay installation of new SCR. Today,
we finalize our proposed approach with
one clarification. To avoid confusion
over the proper interpretation of the
phrase ‘‘in place,’’ we are clarifying that
an existing SCR is one which is fully
installed and capable of operation by
November 1, 2005.
We also proposed that these existing
SCR begin year-round operations no
later than January 1, 2009 to qualify as
RACT/RACM under our presumptive
approach. We noted that year round
operation of existing SCR involves little
to no alteration of existing equipment,
and that EGUs could conduct any
required work during normal outages.
Today, after taking these factors into
account, we finalize our proposed rule.
The year-round operation requirement,
however, will not be federally
enforceable to individual EGUs until
EPA approves a State’s SIP including
the requirement.
c. Comments and Responses
Comment:
Some commenters
supported the proposed determination
described in section (a) that in States
that fulfill their CAIR SO
2
emission
reduction requirements entirely through
EGU emission reductions (i.e. without
reductions from non-EGU sources or
allowing non-EGU sources to opt in to
the CAIR SO
2
trading program),
compliance by EGU sources with an
EPA-approved CAIR SIP or a CAIR FIP
would satisfy the SO
2
RACT
requirement for the sources; and in
States that are subject to CAIR annual
NO
X
emission reduction requirements
and fulfill these requirements entirely
through EGU emission reductions (i.e.
without reductions from non-EGU
sources or allowing non-EGU sources to
opt in to the CAIR annual NO
X
trading
program), compliance by EGU sources
with an EPA-approved CAIR SIP or a
CAIR FIP would satisfy the NO
X
RACT
requirement for the sources, provided
that the sources with existing selective
catalytic reduction (SCR) emission
control technology installed on their
boilers operate that technology on a
year-round basis beginning in 2009. One
commenter supported EPA’s approach
so long as States may pursue additional
reductions from EGUs if needed for
attainment as expeditiously as
practicable. A number of other
commenters opposed the proposed
determination regarding RACT for EGUs
based on a number of issues.
Response:
Based on the rationale
described in the sections above, the
final rule includes a presumption that
compliance with CAIR satisfies SO
2
and
NO
X
RACT/RACM requirements for
EGUs in many areas. Nonetheless, States
can require ‘‘beyond CAIR’’ EGU
controls if a State determines that it is
a necessary and reasonable means to
attain the PM
2.5
standards. Comments
opposing this approach are addressed in
more detail below.
Comment:
A number of commenters
objected to the proposed determination,
arguing that it would result in greater
control requirements and economic
burden on non-EGU sources located in
nonattainment areas. These commenters
urged EPA to adopt a final rule that
provides for implementing the most
cost-effective controls necessary to
attain the standard. They assert that
with the proposed finding that
compliance with CAIR satisfies RACT
for EGUs, the proposed rule would not
provide for the most cost-effective
approach to attainment. They argue EPA
and States should develop cost-
effectiveness guidance that includes all
stationary source control measures and
they should develop SIPs based on the
most economic means to attain the
standard. They make several arguments
to support this position. The
commenters asserted that if an EGU
control is more cost-effective than a
non-EGU control, the EGU should be
subject to ‘‘beyond-CAIR’’ controls.
They also asserted that if EPA chooses
to consider the CAIR rule as satisfying
SO
2
and NO
X
RACT for EGUs, then
other sources should not be subjected to
control costs greater than those found
reasonable under CAIR (i.e., $800/ton).
They believe it would be inequitable to
require smaller sources to pay a higher
cost for emissions reductions than larger
sources, which are a more significant
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contributor to the problem and which
may be able to make more cost-effective
emission reductions. One commenter
also suggested that EPA should
authorize a presumption that emissions
reductions required on electric utilities
under the CAIR will be equivalent to
RACT only if a particular source in a
CAIR State has installed controls that
achieve the average level of control that
EPA has projected will occur for the
particular pollutant under the CAIR
requirements.
Response:
The EPA has determined
that implementation of the CAIR trading
program represents highly cost-effective
controls that will achieve widespread
regional SO
2
and NO
X
emissions
reductions from EGUs and will provide
significant air quality benefits for ozone
and PM
2.5
nonattainment areas. In
developing attainment SIPs and
identifying RACM, States will need to
consider additional cost-effective and
reasonable controls to reach attainment
as expeditiously as practicable. The EPA
does not agree with the commenter’s
argument that controls on non-EGUs
should be no more than the projected
cost of EGU controls under CAIR. The
EPA expects that in order to achieve
attainment as expeditiously as
practicable, some States may need to
adopt control measures for some sources
which cost more per ton but which still
are considered to be reasonable and
cost-effective.
In addition, States must consider the
economic feasibility of implementing a
given control measure. Because of
facility-specific factors, EPA believes it
would be inappropriate to establish a
threshold of control effectiveness (e.g.
dollars per ton) based on control of
EGUs and apply this threshold to all
source categories. The ability of a source
to cost-effectively reduce emissions is
dependent on case-specific factors,
including the ability of the given source
to sustain the cost of control, and
prevailing costs in the specific
geographical location. A direct
correlation between the size of an
emissions source and the economic
feasibility of controls for that source and
location does not necessarily exist.
We also disagree with the commenter
who suggests that RACT requirements
should only be satisfied if a source
achieves an average level of control that
EPA projects to occur under CAIR. The
EPA maintains that the presumption
that CAIR satisfies SO
2
and NO
X
RACT/
RACM for EGUs in most areas is an
appropriate policy. As discussed further
below, we have always recognized that
States could determine RACT for a
single source or group of sources.
Comment:
A number of commenters
opposed the proposed determination
that CAIR would satisfy the SO
2
and
NO
X
RACT requirement for EGUs. The
commenters argued that this
determination is unlawful, that it does
not comply with section 172(c)(1) of the
CAA which requires RACT (i.e. controls
that are technologically and
economically feasible) ‘‘at a minimum’’
for all existing sources in the
nonattainment area, that it would allow
very large stationary sources to escape
cost-effective controls entirely, and that
it is largely based on the legally-
irrelevant contention that CAIR will
reduce emissions more cost-effectively
than RACT. They claim that EPA has no
authority to displace the
Congressionally-mandated RACT
requirement, that CAIR was designed to
address regional pollution transport (not
to be an attainment strategy), and that
EPA should remove these proposed
provisions in the final rule. Commenters
claim that the EPA’s proposed approach
to allow EGU emissions to be addressed
solely through CAIR would undermine
states’ efforts to meet the Federal PM
2.5
health standard, particularly when EGU
sources are among the most cost-
effective to control. Another commenter
claimed that EPA’s proposal allowing
States that choose to fulfill their CAIR
requirements entirely through emission
reductions from EGUs to also use CAIR
to satisfy their SO
2
and NO
X
PM
2.5
RACT requirements, thereby equating
these two requirements for the EGU
sector, is flawed. This commenter
argued that allowing a cap-and-trade
program, such as the CAIR, to substitute
for the RACT requirement undermines
the effectiveness of the controls by
allowing facilities to use allowances to
offset emissions, rather than control
them at the source. The purchase of
allowances, they assert, does not satisfy
RACT requirements.
Response:
The EPA disagrees with
these comments. The final rule does not
displace the RACT requirement for any
sources. Instead, EPA is exercising its
authority to interpret the section 172
RACT and RACM requirements for the
purposes of implementing the 1997
PM
2.5
standards. For the reasons
described in section (b) above, we
believe that States can rely on EPA’s
presumption that compliance with a
CAIR SIP or FIP, meeting certain
requirements, will satisfy the RACT/
RACM requirement for certain EGU
sources. The EPA historically issued
control technology guidelines setting
forth presumptive levels of emissions
control that satisfy the RACT
requirement for a given industry. The
final rule is similar to this practice in
establishing a presumption that SO
2
and
NO
X
reductions under the CAIR
program satisfy the RACT/RACM
requirement for EGUs in CAIR States. In
identifying reasonably available control
measures to ensure attainment as
expeditiously as practicable, States will
need to take CAIR reductions into
account as well as any additional cost-
effective reductions that are
technologically and reasonably
available.
We further find that the attempt by
many commenters to characterize CAIR
as a strategy to address only regional
pollution transport and not an
attainment strategy as overly simplistic.
The EPA analyses for CAIR show that
there are significant air quality benefits
projected for individual nonattainment
areas as a result of SO
2
and NO
X
reductions across the multistate CAIR
region. The Act does not prevent States
from properly crediting measures that
achieve multiple objectives (e.g.
regional transport or local
nonattainment). Moreover, Section
110(a)(2)(D) requires SIPs to contain
adequate provisions to assure that
sources in the State do not contribute
significantly to nonattainment in any
other State. The CAIR rule is an integral
element in meeting the States’ Section
110 attainment obligations.
Accordingly, it is reasonable to
incorporate this consideration in
determining what measures qualify as
RACT/RACM.
Finally, EPA does not interpret the
provisions of Section 172(c)(1) related to
the RACT requirement as precluding
States’ use of a cap and trade approach
as a means of regulating existing sources
and achieving RACT/RACM reductions,
especially in light of Congresses’
expressed authorization to auction
emission rights in Section 172(c)(6).
The EPA has long recognized that
RACT need not apply to individual
sources. As stated earlier, our early
guidance on RACT requirements stated
that States could establish RACT for an
‘‘individual sources or
a group of
sources
.’’ (emphasis added) See Memo.
Strelow (Dec. 1976) and 44 FR 71779.
Importantly, Congress ratified the early
interpretations of RACT and RACM
when it enacted the 1990 Amendments.
See 42 U.S.C. Section 7515 (Clean Air
Act section 193). Our 1986 emissions
trading policy also recognized a number
of advantages offered through
application of a ‘‘bubble’’ approach
including faster compliance with RACT
limits and earlier reductions. Moreover,
Courts have upheld EPA’s approval of
States’ use of ‘‘bubbling’’ multiple units
to meet RACT requirements. See e.g.
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Natural Resources Defense Council
v.
EPA
, 941 F.2d 1207 (finding that EPA
need not adhere to a source specific
RACT determination to satisfy RACT
requirements and acknowledging EPA’s
special knowledge and expertise in the
area.)
Comment:
The EPA’s proposal to
allow EGU emissions to be addressed
solely through CAIR undermines
prospectively States’ efforts to meet the
Federal PM
2.5
health standard. EGU
sources are among the most cost-
effective to control.
Response:
For the reasons described
in section (b) above, EPA believes that
States can rely on EPA’s presumption
that compliance with a CAIR SIP or FIP,
meeting certain requirements, satisfies
the SO
2
and NO
X
RACT/RACM
requirement for certain EGU sources.
Areas can require ‘‘beyond CAIR’’ EGU
controls if a State determines that it is
a necessary and reasonable means to
attain as expeditiously as practicable.
Nonetheless, as discussed above, EPA
believes that implementation of the
CAIR requirements will provide for
substantial progress in attaining the
PM
2.5
standards and that States may
presume that RACT/RACM
requirements are equal to the CAIR level
of control.
Comment:
CAIR fails to address the
need for short-term reductions in PM
2.5
and precursor emissions on high
pollution days. While RACT restricts
emissions over a 1-hour to 24-hour
period, CAIR only provides for an
annual or seasonal cap. Reliance on
CAIR therefore fails to recognize the
importance of reducing short-term
emissions, which was recently
highlighted by the EPA’s own proposal
to tighten the 24-hour PM
2.5
health
standard. Local and short-term adverse
air quality effects of PM
2.5
, must be
addressed in the final rule by requiring
RACT for all major facilities in addition
to CAIR.
Response:
The CAIR program is
oriented toward reducing SO
2
and NO
X
emissions in order to reduce air quality
concentrations on an annual and
seasonal basis. Because all PM
2.5
nonattainment areas were designated
due to violations of the annual standard
(and the two designated areas in
California also violated the 24-hour
standard), the focus of this
implementation rule is attainment of the
annual standard. CAIR is projected to
provide significant air quality benefits
in 2010 and 2015 for eastern PM
2.5
nonattainment areas on both an annual
basis and on a 98th percentile 24-hour
basis.
41
Comment:
The proposal is silent on
the issue of whether EGUs are subject to
direct PM
2.5
emissions RACT
requirements. It is critical that RACT be
required for all facilities with respect
direct PM
2.5
emissions, regardless of a
facility’s participation in CAIR.
Response:
In the final rule and
preamble, EPA has clarified that all
EGUs in nonattainment areas are subject
to RACT/RACM for direct PM
2.5
emissions. The presumption described
above applies only to SO
2
and NO
X
RACT/RACM, not RACT/RACM for
direct PM
2.5
emissions from EGUs.
Comment:
The EPA fails to consider
the geographical distributional impacts
of the emission reductions. Equating
CAIR with RACT fails to take into
account the substantial contribution that
emissions from EGUs within a
nonattainment area may make toward
that area’s PM
2.5
nonattainment
problem. The EPA does not attempt to
explain how such a generalized
determination satisfies RACT for PM
2.5
.
Response:
The establishment of
recommended levels for RACT/RACM is
an area Congress delegated to the
specific expertise of the Agency. Based
on our analysis, we conclude that the
CAIR emissions caps presumptively
represent the level of emissions control
achievable through application of
‘‘reasonably available’’ control
technologies. Nonetheless, in
developing attainment plans, each State
will evaluate the impact of stationary
sources located within the
nonattainment area in developing its
attainment strategies for the local area.
Comment:
A few commenters stated
that EPA should explain how this
proposal would be implemented for
States that request an extension of an
attainment date because attaining in 5
years or less is impracticable; i.e.,
whether EPA would still hold to its
interpretation that CAIR equals RACT
for EGUs and not require additional
reductions from EGUs even if an area
cannot attain in 5 years and controls on
EGUs could lead it to attain more
expeditiously. These commenters argue
that, in considering if additional RACT
is needed in states that obtain
extensions of the attainment deadline
after 2010, EPA cannot ignore potential
RACT for electric generating units any
more than they would be allowed
legally to avoid consideration of any
other RACT candidates. One commenter
41
See the regulatory impact analysis chapter on
air quality for the 2006 PM NAAQS review at
http://www.epa.gov/ttn/ecas/regdata/RIAs/
Chapter%204-Air%20Quality.pdf
.
is particularly concerned that States
would not include EGUs in their RACT
determinations and instead require
smaller industrial boilers or process
heaters to control emissions.
Response:
The EPA’s determination
regarding CAIR and RACT is not limited
to areas attaining within five years. The
Agency’s rationale is presented in the
‘‘final rule’’ section above. We disagree
that the CAIR–RACT presumptions
necessarily shift emission control
burdens from EGUs to smaller industry
boilers and process heaters because, in
implementing the RACM requirement,
the State may include an evaluation of
control options on those sources as part
of their RACT/RACM analyses. As
stated above, EPA concluded that the
CAIR compliance dates represent an
aggressive schedule that reflects the
limitations of the labor pool, and
equipment/vendor availability, and
need for electrical generation reliability
for installation of emission controls.
Accordingly, additional controls on
EGUs may not be a reasonably available
control measure that can be effectively
implemented in a manner that advances
an area’s attainment date.
Comment:
The EPA designated many
partial counties nonattainment for PM
2.5
solely because the areas contained EGU
emission sources thought to cause or
contribute to violations of the NAAQS.
In implementing attainment plans, it
makes sense to consider further control
of these sources, and because they are
located in nonattainment areas, the
ability to do so is provided for and legal
under the CAA.
Response:
The EPA designated PM
2.5
nonattainment counties because they
either had a violating monitor or they
contributed to a nearby air quality
problem. Importantly, EPA designated
these areas without considering the air
quality benefits expected in the future
from CAIR. Accordingly, the fact that an
EGU is located in a partial county and
we included the partial county in the
nonattainment area because we believe
that the EGU was causing or
contributing to the nonattainment
violations, does not equate with a
finding that more than CAIR is required
to remedy the nonattainment problem.
Nonetheless, EPA believes that States
should evaluate the impact of stationary
sources in all designated counties,
including those partial counties noted
by the commenter, in its assessment of
reasonably available control strategies to
ensure attainment as expeditiously as
practicable.
Comment:
The EPA should adopt the
Ozone Transport Commission’s (OTC’s)
approach to cap-and-trade programs.
When the OTC developed its NO
X
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Budget Program (which was the basis
for EPA’s NO
X
SIP call and
subsequently CAIR), it assumed that
RACT was applied first. Thus the cap-
and-trade program operated in an
environment that assumed RACT was in
force, not in lieu of RACT.
Response:
Under the ozone national
ambient air quality standards, NO
X
and
VOC RACT have been implemented
progressively for the past 30 years or
more, prior to development of the NO
X
SIP call regional control program. In
contrast, the PM
2.5
implementation
program is the first instance in which
we have required RACT/RACM
specifically for fine particle pollution.
For this reason, the CAIR program is not
operating with SO
2
and NO
X
RACT
limits already in place for attainment of
the PM
2.5
standards. Nonetheless, as
discussed above, EPA believes that
implementation of the CAIR
requirements will provide for
substantial progress in attaining the
PM
2.5
standards and that States may
presume that RACT/RACM
requirements are equal to the CAIR level
of control.
Comment:
A few commenters stated
that EPA should clarify and modify the
part of its proposal that explains why a
State cannot rely on EPA’s
determination that CAIR can satisfy the
NO
X
RACT requirement for PM
2.5
if the
State ‘‘elect[s] to allow non-EGU sources
to voluntarily enter the EPA-
administered CAIR trading program
through an opt-in provision in the CAIR
model rule.’’ (70 FR 66025 col. 3). These
commenters believe that this part of the
proposal might be construed to preclude
States subject to both the NO
X
SIP Call
and included in the CAIR region for
ozone from relying on the NO
X
RACT
determination for PM
2.5
if the States
choose ‘‘to bring their non-CAIR
[including non-EGU] NO
X
SIP Call
trading sources into the CAIR ozone
season NO
X
cap and trade program.’’ (70
FR 49708, 49728 col. 3) (August 24,
2005). The commenters assert that EPA
gave States the option of bringing non-
EGU NO
X
SIP Call sources into the
CAIR seasonal NO
X
trading program to
ensure that non-CAIR sources, including
non-EGUs, that are subject to the NO
X
SIP Call rule would not be ‘‘stranded,’’
starting in 2009, by being left in an
ozone season NO
X
control program with
no EGU trading partners. The
commenters argued that ‘‘EGUs should
not be penalized, in the form of denial
of CAIR–RACT treatment, as a result of
States exercising their option to avoid
financial and compliance difficulties for
non-EGUs that otherwise would be left
without allowance trading partners in
the EGU sector after the NO
X
SIP Call
trading program ends in 2008.’’ These
commenters point to EPA’s
determination in the final Phase 2 ozone
implementation rule, that participation
in the CAIR trading programs can satisfy
NO
X
RACT for ozone even if a State
brings non-EGUs in the NO
X
SIP Call
trading program into the trading
program after 2008,
see
70 FR 71657 col.
2, provided the State retains an ‘‘EGU
[emission] budget under CAIR that is at
least as restrictive as the EGU budget
that was set in the State’s NO
X
SIP call
SIP,’’ id. At 71658 col. 1. These
commenters argue that EPA should
make a similar determination here
regarding NO
X
RACT for purposes of
PM
2.5
NAAQS implementation.
Response:
All states with EPA
approved CAIR SIPs or subject to a
CAIR FIP implementing the annual NO
X
emission reduction requirements, and
obtaining those reductions solely from
EGUs may rely on EPA’s determination
that CAIR presumptively satisfies NO
X
RACT/RACM for PM
2.5
for these
sources. This determination is
unaffected by whether or not a State
permits NO
X
SIP Call non-EGUs to
participate in the CAIR ozone season
trading program. In the final rule, we
have included the presumption that
NO
X
RACT/RACM for PM
2.5
is satisfied
for EGUs complying with a CAIR SIP or
CAIR FIP implementing the annual
CAIR NO
X
emission reduction
requirements (provided the State
implementation of the CAIR NO
X
annual trading program includes EGUs
only).
42
In the final ozone implementation
rule, EPA addressed numerous issues
relating to the transition from the NO
X
SIP Call to the CAIR ozone season
trading program, including the impact
of bringing NO
X
SIP Call non-EGUs into
the CAIR ozone season trading program.
Commenters’ suggestion that these
determinations are relevant to this PM
2.5
implementation rule ignores the fact
that both the NO
X
SIP Call and the CAIR
ozone season trading program are
seasonal, not annual, trading programs.
The NO
X
SIP Call EGU and non-EGU
budgets are seasonal NO
X
budgets and
do not address annual NO
X
emissions.
As discussed above, PM
2.5
levels year-
round contribute to an area’s annual
average concentration, and NO
X
emissions during non-summer months
42
EPA’s CAIR–RACT presumption also would
not apply if a State required sources other than
EGUs to achieve a portion of the reductions
required by CAIR (e.g., the State’s CAIR SIP
achieved some reductions from EGUs but took
credit for non-EGU reductions achieved under new,
more stringent requirements implemented to meet
NO
X
SIP call caps). Under the CAIR rule such a
State would not be eligible to participate in the
EPA-administered CAIR trading system.
contribute to nitrate concentrations,
which are typically highest in cooler
temperatures. For these reasons, EPA
believes it would be inappropriate to
accept commenters’ suggestion.
8. What Are the Required Dates for
Submission and Implementation of
RACT?
a. Background
The EPA requested comment on a
general approach for the dates for
submission and implementation of
RACT rules. The final rule retains the
proposed approach, as described in the
following section.
b. Final Rule
The final rule requires the following:
(1) Date of submission. States must
submit adopted RACT rules to EPA
within 3 years of designation, at the
same time as the attainment
demonstration due in April 2008.
(2) Dates for implementation of
control measures. States should also
implement any measures determined to
be RACT expeditiously, as required by
section 172. Implementation of RACT
measures should in no case start later
than the beginning of the year before the
nominal attainment date. For example,
if an area has an attainment date of
April 2010, then any required RACT
measures should be in place and
operating no later than the beginning of
2009. This is intended to help provide
for clean air in calendar year 2009. As
discussed in section II.D, if other criteria
are also met, EPA could then grant the
area a 1-year attainment date extension
if the air quality level in the 3rd of the
3 years was below the level of the
standard. If the area observes a second
year of clean air, EPA could grant a
second 1-year attainment date
extension. In this case, the 2009 to 2011
period would then be reviewed to assess
whether the area attains the standards.
(3) Provisions for a demonstration that
additional time is needed. While EPA
expects that States will implement
required RACT controls by January 2009
in most situations, there may be cases
where additional time is needed to
implement an innovative control
measure or to achieve a greater level of
reduction through a phased approach. If
a State has provided an adequate
demonstration showing that an
attainment date extension would be
appropriate for an area, then the State
may consider phasing-in certain RACT
controls after January 2009. The EPA
would allow the implementation of
selected RACT controls after January
2009 if the State can show why
additional time is needed for
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implementation, and such delayed
implementation still would need to be
on a schedule that provides for
expeditious attainment. In no event
could the State wait to implement RACT
controls until the last few years prior to
the attainment date without an adequate
rationale for why earlier
implementation was not feasible.
c. Comments and Responses
Comment:
One commenter supported
EPA’s position that implementation of
RACT and RACM by January 1, 2009 is
necessary to achieve the effect on air
quality for calendar year 2009.
Response:
The EPA agrees with this
comment.
Comment:
Some commenters
supported allowing for an
implementation schedule that allowed
for implementation of RACT and RACM
for a time frame extending beyond 2009.
These commenters favored such an
approach if States provided an adequate
demonstration of why the measures
cannot be implemented earlier.
Commenters noted that a phased
approach to emissions reductions in
some cases could lead to additional
reductions that could not occur by 2009.
Response:
The EPA agrees with these
comments.
Comment:
One commenter believed
that so long as a State demonstrates
attainment by 2015, EPA should not
require implementation of any RACT
measures. The commenter further
asserted that it would be bad policy to
require costly emissions reductions
through imposition of RACT on areas
expected to attain the standards through
other means by 2015.
Response:
The EPA disagrees with
this comment. The CAA requires States
to demonstrate that the attainment plan
will attain the standards as
expeditiously as practicable and must
include RACT and RACM. The
requirement for ‘‘reasonable’’ measures
does not require that any theoretical
measure be implemented, but does
require implementation of those
reasonable measures which could
advance the attainment date by at least
1 year. Given the health effects
associated with PM
2.5
, EPA believes this
approach is sound public policy.
9. Which Pollutants Must Be Addressed
by States in Establishing RACT and
RACM Limits in Their PM
2.5
Attainment
Plans?
a. Background
In the proposed rule, and in the final
rule as discussed in detail in section
II.A above, EPA discusses the pollutants
which States must address in the
attainment plans, in particular with
respect to RACT, RACM and NSR.
These pollutants include not only direct
PM
2.5
, but also gaseous precursors to the
formation of PM
2.5
. In general, the
decisions that States and EPA make
with respect to which precursors are
significant contributors to an area’s
PM
2.5
nonattainment problem define the
pollutants and sources to be addressed
by States in developing RACT and
RACM.
b. Final Rule
In the final rule, in establishing RACT
and RACM limits, those RACT and
RACM limits must address:
—Direct emissions of PM
2.5
—SO
2
, a precursor to PM
2.5
formation,
and
—NO
X
, unless a State makes a finding
that NO
X
emissions from sources in
the State do not significantly
contribute to the PM
2.5
problem in a
given nonattainment area.
The EPA generally presumes that
RACT and RACM limits are not needed
for ammonia or VOC unless that State or
EPA determines otherwise for a given
nonattainment area. RACT and RACM
limits are needed for ammonia if a State
or EPA makes a finding that ammonia
emissions significantly contribute to the
PM
2.5
problem in a given nonattainment
area, and thus finds that control of
ammonia would help address the PM
2.5
problem. RACT and RACM limits are
needed for VOC only if a State or EPA
makes a finding that VOC emissions
significantly contribute to the PM
2.5
problem in a given nonattainment area.
(As a point of clarification, ‘‘VOCs,’’
which are gaseous organic precursors to
the chemical formation of secondary
organic aerosol, are treated differently
from semivolatile or nonvolatile organic
compounds which are addressed as
directly emitted PM
2.5
). Issues related to
the finding of ‘‘significant contribution’’
for these pollutants are discussed in
Section II.A above.
10. Under the PM
2.5
Implementation
Program, When Does a State Need To
Conduct a RACT Determination for an
Applicable Source That Already Has a
RACT, BACT, LAER, or MACT
Determination in Effect?
a. Background
For PM
2.5
nonattainment areas, States
are required to implement the RACT
requirement to reduce emissions of
direct PM
2.5
and PM
2.5
precursors from
applicable sources. The EPA anticipates
that for some sources located in PM
2.5
nonattainment areas, the State would
have previously conducted RACT
determinations for VOC or NO
X
under
the 1-hour ozone standard, or for direct
PM
10
emissions under the PM
10
standards. Some of the RACT
determinations established under these
other programs would be relatively
recent while other determinations may
be more than 10 years old. In some
cases, a new RACT determination might
reach the conclusion that the
preexisting determination is still valid
and would require the installation of
similar control technology because the
relevant pollutant was addressed, the
same emission points were reviewed,
and the same fundamental control
techniques would still have similar
costs. In other cases, however, a new
RACT analysis could determine, for
example, that better technology has
become available, and that cost-effective
emission reductions are achievable.
In the proposed rule, the EPA
requested comments on a general
approach to taking prior RACT
determinations into account, and within
the general approach, invited comments
on two specific questions: (1) Should
new RACT determinations be required
for all existing determinations that are
older than a specified amount of time
(such as 10 years old)?; and (2) what
supporting information should a State
be required to submit as part of its
certification to demonstrate that a
previous RACT analysis meets the
RACT requirement currently for
purposes of the PM
2.5
program?
In the proposed rule, EPA also noted
that sources subject to RACT may also
have been subject to other prior
technology determinations such as
BACT, LAER or MACT determinations.
The proposed rule requested comment
on approaches to taking these prior
technology determinations into account.
b. Final Rule
The EPA has determined that it is
appropriate to follow the approach in
the proposed rule, which is described
below. State RACT SIPs for PM
2.5
must
assure that RACT is met, either through
a new RACT determination or a
certification that previously required
RACT controls represent RACT for
PM
2.5
.
Where a State adopted and EPA
approved a control measure as RACT for
a pollutant emitted from a specific
stationary source or source category
under another NAAQS program, the
State may submit as part of its SIP
revision a certification, with appropriate
supporting information, that the
previous determination represents a
current RACT level of control for those
emissions for purposes of the PM
2.5
program. Otherwise, the State should
revise the SIP to reflect a modified
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RACT requirement for specific sources
or source categories.
In cases where the State’s prior RACT
analysis under another NAAQS program
concluded that no additional controls
were necessary, a new RACT
determination is required for that
source. In cases where the previous
RACT determination did not require any
controls on the source, it is more likely
that a new review might find that
emission controls are now economically
and technically feasible. This is because
emissions reductions from a potential
control measure are likely to be greater,
and the cost per ton of emission
reduction is likely to be lower, than in
the case of a source that previously
installed controls to meet RACT under
another program.
A RACT determination for a source or
source category subject to a prior RACT
determination is also required for any
pollutants that were not the subject of
the prior RACT determination, but
which the State has determined should
be regulated for purposes of PM
2.5
. The
EPA advises that the State should
closely review any existing RACT
determinations established under
another NAAQS program. For RACT
certifications and determinations, States
are to consider new information that has
become available since the earlier RACT
determination. For example, where
updated information on control
technologies is presented as part of
notice-and-comment rulemaking,
including a RACT SIP submittal for
sources previously controlled, States
(and EPA) must consider the additional
information as part of that rulemaking.
Existing EPA guidance on control
technologies can be used to help inform
RACT decisions. However, EPA believes
it may not be sufficient for a State to
rely on technology guidance that is
several years old and issued to provide
recommendations on control measures
and levels for a different NAAQS in
evaluating RACT for PM
2.5
.
With respect to prior technology
determinations other than RACT, the
final rule provides that:
(1) Prior BACT and LAER
Determinations. In many cases, but not
all, best available retrofit technology
(BACT) or lowest achievable emission
rate (LAER) provisions for new sources
would assure at least RACT level
controls on such sources. The BACT/
LAER analyses do not automatically
ensure compliance with RACT since the
regulated pollutant or source
applicability may differ and the
analyses may be conducted many years
apart. States may, however, rely on
information gathered from prior BACT
or LAER analyses for the purposes of
showing that a source has met RACT to
the extent the information remains
valid. We believe that the same logic
holds true for emissions standards for
municipal waste incinerators under
CAA section 111(d) and NSR/PSD
settlement agreements. Where the State
is relying on these standards to
represent a RACT level of control, the
State should present its analysis with its
determination during the SIP adoption
process.
(2) Compliance With MACT
Standards Affecting VOC. In situations
where the State has determined VOC to
be a significant contributor to PM
2.5
formation in an area, compliance with
MACT standards may be considered in
VOC RACT determinations. For VOC
sources subject to MACT standards,
States may streamline their RACT
analysis by including a discussion of the
MACT controls and relevant factors
such as whether VOCs are well
controlled under the relevant MACT air
toxics standard, which units at the
facility have MACT controls, and
whether any major new developments
in technologies or costs have occurred
subsequent to establishment of the
MACT standards. We believe that there
are many VOC sources that are well
controlled (e.g., through add-on controls
or through substitution of non-VOC
non-HAP materials for VOC HAP
materials) because they are regulated by
the MACT standards, which EPA
developed under CAA section 112. Any
source subject to MACT standards must
meet a level that is as stringent as the
best-controlled 12 percent of sources in
the industry. Examples of these HAP
sources that may effectively control
VOC emissions include organic
chemical plants subject to the hazardous
organic NESHAP (HON),
pharmaceutical production facilities,
and petroleum refineries.
43
We believe
that, in many cases, it will be unlikely
that States will identify VOC emission
controls more stringent than the MACT
standards that are not prohibitively
expensive and are thus unreasonable.
We noted our view that this will allow
States, in many cases, to conclude that
the control measures implemented to
meet MACT standards satisfy any
requirement for VOC RACT.
(3) Compliance With MACT
Standards Affecting PM
2.5
Emissions.
Compliance with MACT standards may
be considered in direct PM
2.5
RACT
43
There are some MACT categories for which it
may not be possible to determine the degree of VOC
reductions from the MACT standard without
additional analysis; for example, the miscellaneous
metal parts and products (40 CFR part 60, subpart
MMMM) due to the uncertainty of the compliance
method that will be selected.
determinations. For direct PM
2.5
sources
subject to MACT standards, States may
streamline their RACT analysis by
including a discussion of the MACT
controls and relevant factors such as
whether PM
2.5
emissions are well
controlled under the relevant MACT air
toxics standard, which units at the
facility have MACT controls, and
whether any major new developments
in technologies or costs have occurred
subsequent to the MACT standards. We
believe that there are many direct PM
2.5
sources that are well controlled (e.g.,
through add-on controls that represent
state-of-the-art measures for PM
2.5
reduction) because they are regulated by
the MACT standards which EPA
developed under CAA section 112. For
some MACT standards, PM
2.5
is used as
a surrogate for achieving MACT for
HAPs such as heavy metals. Any source
subject to MACT standards must meet a
level that is as stringent as the best-
controlled 12 percent of sources in the
industry. We believe that there will be
sources for which it will be unlikely
that States will identify emission
controls more stringent than the MACT
standards that are not prohibitively
expensive and are thus unreasonable. In
addressing whether a MACT standard
represents best controls for PM
2.5
, it is
important that the State consider all
PM
2.5
sources at a given facility and the
nature of the PM limit (i.e., whether the
limit ensures control of the fine fraction
of particulate matter). Also, the State
should evaluate the degree of capture of
PM
2.5
—that is, the amount of PM
2.5
that
is collected and sent to a pollution
control device in addition to the
efficiency of the device itself. This
evaluation should consider the PM
2.5
emissions reductions that could be
achieved by improving the degree of
capture.
(4) Year-Round Controls for NO
X
. In
some cases, sources subject to NO
X
RACT for PM will also be subject to
controls under the NO
X
SIP Call. In the
8-hour ozone implementation rule, EPA
concluded that certain sources which
have installed emission controls to
comply with the NO
X
SIP call would be
deemed to meet NO
X
RACT for the
purposes of the 8-hour ozone
implementation program. Some of these
sources subject to the NO
X
SIP call may
choose to control NO
X
emissions only or
primarily during the ozone season. For
purposes of PM
2.5
, however, EPA
concludes that the operation of emission
controls only or primarily during the
ozone season would not constitute
RACT for PM
2.5
purposes. Indeed PM
2.5
control programs must address annual
average concentrations, and in many
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areas nitrate concentrations are
generally highest in the winter.
Therefore, RACT for PM
2.5
is year-round
operation of controls. For sources
subject to both the NO
X
SIP call and
NO
X
RACT for PM, we believe that, in
most cases, the additional costs of
running the NO
X
SIP call controls year-
round would impose only modest,
reasonable additional costs and the cost
effectiveness would be better than the
average cost effectiveness for many
other sources subject to PM RACT. (See
further discussion in section F.7 above
related to EGU sources subject to CAIR
requirements for NO
X
).
c. Comments and Responses
Comments:
A number of commenters
agreed with the requirement for the
State to conduct a new RACT
determination for any source for which
the State’s prior RACT analysis under
another NAAQS program concluded
that RACT was defined as no additional
controls. One commenter noted that for
a source having a previous RACT
determination for ozone or PM
10
to
show that its level of control currently
meets RACT for PM
2.5
purposes, the
source must provide supporting
documentation showing that the
previous RACT determination was
based on the same universe of controls
that are ‘‘reasonably available’’ for the
source in the present day.
Response:
The EPA agrees with these
comments.
Comments:
A few commenters
recommended that EPA clarify that
RACT determinations resulting only in
‘‘operational changes’’ should be treated
in an equivalent manner as those
resulting in no controls. The
commenters suggested that, unlike
‘‘physical modification,’’ such
operational changes should always be
revisited with a new RACT
determination.
Response:
The EPA does not agree
with the implicit recommendation to
impose different RACT review
requirements based on the types of
control previously implemented. The
EPA believes that a reassessment of
RACT is warranted, irrespective of the
type of control previously implemented,
to consider the reasonableness of
modifying or adding controls in the
particular circumstances. Furthermore,
we are concerned that making such a
distinction based upon the fairly broad
term ‘‘operational change’’ would be
difficult to interpret and implement,
and would invite unnecessary disputes
concerning the application of the term.
Comment:
Commenters differed on
whether new RACT determinations
should be required for all existing
determinations made before a specific
date, and on what that date should be.
Some commenters recommended that
EPA allow States to rely on any
previous RACT determinations made
after 1990, and one commenter
recommended that EPA require States to
review only those older than 10–15
years, another recommended 10 years.
One commenter believed that a 15-year
period would be reasonable where
previous controls were installed, to
allow for a 15-year amortization of the
cost of those controls. Other
commenters recommended that new
RACT determinations be made for any
RACT determinations older than 5
years. Another commenter
recommended that all RACT
determinations should be reviewed.
Response:
The EPA has not included
any specific time frame in the final rule.
The EPA agrees that the more recent the
RACT determination, the greater the
probability that technology advances or
decreases in control cost will not have
occurred. At the same time, technology
advances and decreases in control cost
can and have occurred frequently.
Accordingly, we believe it is necessary
for States to review whether such
technology advances or decreases in
control cost have occurred before
relying on previous RACT
determinations. We do not believe there
is any specific date or age that could be
identified after which States could
ensure that no technology advances or
decreases in control cost will have
occurred.
Comment:
A number of commenters
expressed concerns with the resources
required to conduct the certifications
required by the proposed approach, and
argued that expending the resources
required to review and to certify
previous RACT determinations would
not be productive. One commenter
recommended that EPA provide
guidance on the previous RACT
categories for which old RACT
determinations are believed to be out of
date. Another commenter asserted that
the only possible exception to the
acceptability of previous RACT
measures for purposes of the ozone
standards would be when the new
RACT is year-round for an existing
ozone-season RACT measure.
Response:
The EPA believes that the
proposed certification approach strikes
an appropriate balance in requiring
States to verify whether previous RACT
determinations currently represent an
appropriate RACT level of control for
PM
2.5
purposes, while stopping short of
requiring an exhaustive re-analysis for
all RACT sources. The EPA believes that
much of the resource concerns
expressed in comments were based
upon concerns that VOC sources are
very numerous, and that this approach
would require detailed review for these
sources. As noted previously, a RACT
analysis for VOC sources is required
only if a State makes a finding that VOC
sources significantly contribute to
nonattainment in the State. We believe
the commenters likely overestimate the
resource implications of the certification
process for prior RACT determinations.
Another mitigating factor is that many
of these same sources would be
reviewed for purposes of implementing
the eight-hour ozone standard. On the
other hand, where a State or EPA
determines that it is appropriate to
regulate VOC sources for PM
2.5
, EPA
believes that it likely would be
productive to review the previous
determination for such sources, some of
which have not been reviewed for many
years.
Comment:
One commenter believed
that EPA should acknowledge detailed
RACT and RACM analyses for the South
Coast and San Joaquin Valley in
California prepared during the 1990s for
purposes of implementing the ozone
and PM
10
standards. The commenter
believes that EPA acceptance of these
determinations as RACT for PM
2.5
would enable States to focus resources
on developing new measures needed for
attainment.
Response:
The EPA agrees that States
should focus resources on new
technologies and new developments. At
the same time, EPA recognizes that for
most source categories, new technology
continues to be developed, and new
information continues to be generated.
Thus, even recent RACT determinations
for a given source category may be
outdated. Hence, the certification
approach in the rule for the relevant
sources or source categories is a
reasonable approach which is designed
to provide for the type of focused efforts
suggested by the commenter.
Comment:
One commenter believed
that a State certification should only
have to identify the existing RACT
levels in a SIP and pollutants affected,
but the State should not be required to
provide any additional information.
Response:
The EPA disagrees with
this comment. The EPA believes that
prior technology determinations should
be taken into account in the RACT
determination process. In reviewing
existing RACT determinations, the State
should provide supporting information
to show that the existing technology in
use should still be considered RACT, or
it should show that there have been
technology advances or cost reductions
that have occurred since the previous
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RACT limits were developed that make
lower emissions technically and
economically feasible in the context of
RACT and would contribute to
advancing the attainment date by at
least one year.
Comment:
Some commenters
supported EPA’s requirement for year-
round operation of NO
X
pollution
control devices as RACT, given that
PM
2.5
is an annual standard, while
ozone is a summertime problem.
Response:
The EPA agrees with these
comments.
Comment:
One commenter concluded
that BACT and LAER determinations
should be considered to satisfy RACT,
regardless of the date they were made,
because BACT and LAER by definition
are more stringent than RACT.
Response:
The EPA disagrees with
this comment. The EPA believes that in
many cases, but not all, BACT and
LAER would assure RACT level of
controls. Reasons that BACT and LAER
might not satisfy RACT include: The
pollutant of concern could have been
different, the applicability threshold for
BACT and LAER may have excluded
smaller sources potentially subject to
RACT controls, and technology
advances or reductions in control costs
may have occurred since the old
determination was conducted.
Comment:
One commenter
recommended that EPA allow States to
use information gathered from prior
BACT or LAER analyses to complete the
RACT determination, as was allowed in
the 8-hour ozone NAAQS
implementation rule.
Response:
The final rule allows for
use of such information, to the extent it
remains valid, to inform a certification
by the State that BACT or LAER
technology continues to exceed what
would currently be considered RACT.
Comment:
Some commenters argued
that any MACT determination that
controls the pollutants of concern
should be more than sufficient to satisfy
RACT. Some commenters made similar
recommendations regarding specific
standards where PM limits were
developed as a surrogate for HAPs, such
as the MACT standard for integrated
iron and steel mills, the MACT standard
for iron and steel foundries, and the
section 129 standards for waste to
energy facilities.
Response:
While agreeing that MACT
controls are relevant, the EPA disagrees
that all MACT determinations should be
automatically considered to satisfy
RACT. Reasons include: A MACT
standard aimed at toxics might not
ensure that the relevant PM
2.5
pollutant(s) are well controlled, MACT
applicability provisions might have
excluded units potentially subject to
RACT, and technology advances or
reductions in control costs might have
occurred since EPA conducted the
MACT analysis. The EPA believes that
the State should review whether
technology advances have occurred
including available ‘‘beyond the MACT
floor’’ technologies that may be
reasonable in the context of RACT for
PM
2.5
nonattainment, but which were
not selected as MACT for purposes of
implementing section 112. The EPA
believes that RACT analyses should
evaluate whether increased capture of
PM
2.5
could be achieved, and whether
an increased efficiency in controlling
the fine fraction of particulate matter is
reasonably available. The EPA has,
however, added a specific recognition
that MACT standards can reduce PM
2.5
as well as VOC, and that PM
2.5
information gathered for MACT
standards development may inform a
State’s conclusions on available
technologies for direct PM
2.5
emissions.
Comment:
One commenter expressed
a concern that EPA should not presume
that MACT represents RACT where the
MACT rule allows for a risk-based
exemption from the control technology
requirement.
Response:
The EPA agrees with this
comment.
11. How Should Condensable Emissions
Be Treated in RACT Determinations?
a. Background
Certain commercial or industrial
activities involving high temperature
processes (fuel combustion, metal
processing, cooking operations, etc.)
emit gaseous pollutants into the ambient
air which rapidly condense into particle
form. The constituents of these
condensed particles include, but are not
limited to, organic material, sulfuric
acid, and metals. In general,
condensable emissions are taken into
account wherever possible in emission
factors used to develop national
emission inventories, and States are
required under the consolidated
emissions reporting rule (CERR)
44
to
report condensable emissions in each
inventory revision. Currently, some
States have regulations requiring
sources to quantify condensable
emissions and to implement control
measures for them, and others do not. In
1990, EPA promulgated Method 202 in
Appendix M of 40 CFR Part 51 to
quantify condensable particulate matter
emissions. In the proposed rule, EPA
discussed and requested comment on
44
The consolidated emissions reporting rule was
published in the
Federal Register
on June 10, 2002,
pages 39602–39616.
issues related to condensable emissions
in RACT determinations.
In the proposed rule, we noted that
EPA is in the process of developing
detailed guidance on a new test method
which quantifies and can be used to
characterize the constituents of the
PM
2.5
emissions including both the
filterable and condensable portion of the
emissions stream. We also noted that
when a source implements either of
these test methods addressing
condensable emissions, the State will
likely need to revise the source’s
emissions limit to account for those
emissions that were previously
unregulated. For the purposes of
determining RACT applicability and
establishing RACT emission limits, EPA
indicated in the proposal that it intends
to require the State to adopt the new test
method once EPA issues its detailed
guidance. This guidance would be for
use by all sources within a PM
2.5
nonattainment area that are required to
reduce emissions as part of the area’s
attainment strategy.
b. Final Rule
Issues and comments related to test
method and emissions limit issues for
direct PM
2.5
for RACT, including
discussion of test methods for
condensable PM
2.5
, are discussed in
section II.L.3 of this preamble. The EPA
recognizes that in some cases
condensable emissions are more
difficult to control than filterable
emissions. However, condensable
emissions may be assumed to be almost
entirely in the 2.5 micrometer range and
smaller, so these emissions are
inherently more significant for PM
2.5
than for prior particulate matter
standards addressing larger particles.
Therefore, EPA encourages States to
consider the potential for reducing
condensable emissions when evaluating
potential measures for RACT.
12. What Criteria Should Be Met To
Ensure Effective Regulations To
Implement RACT and RACM?
a. Final Rule
After the State has identified a RACT
or RACM measure for a particular
nonattainment area, it must then
implement that measure through a
legally enforceable mechanism (e.g., a
State rule approved into the SIP). The
legally enforceable mechanism must
meet four important criteria.
First, the baseline emissions from the
source or group of sources and the
future year projected emissions must be
quantifiable so that the projected
emissions reductions from the sources
can be attributed to the specific
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measures being implemented. It is
important that the emissions from the
source category in question are
accurately represented in the baseline
inventory so that emissions reductions
are properly calculated. In particular, it
is especially important to ensure that
both the filterable and condensable
components of PM
2.5
are accurately
represented in the baseline since
traditional Federal and State test
methods have not included the
condensable component of particulate
matter emissions and have not required
particle sizing of the filterable
component.
Second, the control measures must be
enforceable. This means that they must
specify clear, unambiguous, and
measurable requirements. When
feasible, the measurable requirements
for larger emitting facilities should
include periodic source testing to
establish the capability of such facilities
to achieve the required emission level.
Additionally, to verify the continued
performance of the control measure,
specific monitoring programs
appropriate for the type of control
measure employed and the level of
emissions must be included to verify the
continued performance of the control
measure. The control measures and
monitoring program must also have
been adopted according to proper legal
procedures.
Third, the measures must be
replicable. This means that where a rule
contains procedures for interpreting,
changing, or determining compliance
with the rule, the procedures are
sufficiently specific and nonsubjective
so that two independent entities
applying the procedures would obtain
the same result.
Fourth, the control measures must be
accountable. This means, for example,
that source-specific emission limits
must be permanent and must reflect the
assumptions used in the SIP
demonstration. It also means that the
SIP must establish requirements to track
emission changes at sources and
provide for corrective action if
emissions reductions are not achieved
according to the plan.
b. Comments and Responses
There were no comments on this
section. The language above is very
similar to the language in the proposal.
G. Reasonable Further Progress (RFP)
1. Background
Clean Air Act Section 172(c)(2)
requires that plans for nonattainment
areas ‘‘shall require reasonable further
progress,’’ which as defined in Section
171(1) ‘‘means such annual incremental
reductions in emissions of the relevant
air pollutant as are required by this part
or may reasonably be required by the
Administrator for the purpose of
ensuring attainment of the applicable
national ambient air quality standard by
the applicable date.’’ This section
describes the requirements the
Administrator is establishing for states
to achieve reasonable further progress.
In general terms, the goal of these RFP
requirements is for areas to achieve
generally linear progress toward
attainment. The RFP requirements were
included in the Clean Air Act to assure
steady progress toward attaining air
quality standards, as opposed to
deferring implementation of all
measures until the end date by which
the standard is to be attained.
2. Requirements for Areas With
Attainment Dates of 2010 or Earlier
a. Background
In 40 CFR 51.1009(b)(1) of the
proposed rule, EPA proposed that a
State which submits an implementation
plan that demonstrates that an area will
achieve attainment by 2010 (i.e.,
achieves attainment level emissions
during 2009) would not be required to
submit a separate reasonable further
progress plan for that area. In such
cases, EPA proposed that the attainment
demonstration would also be considered
to demonstrate that the area is achieving
RFP.
b. Final Rule
In the final rule, EPA is maintaining
the approach described in the proposed
rule. An area that demonstrates
attainment by 2010 will be considered
to have satisfied the RFP requirement
and need not submit any additional
material to satisfy the RFP requirement.
The EPA will view the attainment
demonstration as also demonstrating
that the area is making reasonable
further progress toward attainment.
c. Comments and Responses
Comment:
A number of commenters
supported EPA’s view that a
demonstration of attainment by 2010
would also demonstrate that the area is
making reasonable further progress
toward attainment.
Response:
The EPA appreciates the
support and is adopting the supported
approach.
Comment:
A set of commenters
objects to EPA’s proposal, arguing that
EPA cannot waive RFP requirements for
areas where the state purports to
demonstrate attainment. These
commenters believe that Subpart 4 of
Part D requires milestones prior to 2009,
and these commenters believe that even
Subpart 1 requires a demonstration of
interim progress that EPA cannot waive.
Response:
In brief, EPA is not waiving
the RFP requirements for any area.
Instead, EPA is concluding that a
demonstration of attainment by 2010
also serves to demonstrate achievement
of RFP. If the state submittal purports to
demonstrate attainment but does not
adequately make this demonstration,
then the submittal also would not
demonstrate achievement of RFP. The
nature of the RFP requirement would
then depend on whether the remedied
attainment demonstration provides for
attainment by 2010. Finally, as
discussed above, EPA believes that
Subpart 4 requirements do not apply to
PM
2.5
plans. More detailed discussion of
this comment and EPA’s response are
provided in the response to comments
document.
3. Requirements for Areas With
Attainment Dates Beyond 2010
a. Background
The proposed rule required a State to
submit an RFP plan along with its
attainment demonstration and SIP due
in April 2008 for any area for which the
State demonstrates that 2011 or later is
the most expeditious attainment date.
EPA proposed that the 2008 RFP plan
must provide adequate emission
reductions by 2009
45
and, in some
cases, by 2012. The plan must
demonstrate that emissions will decline
in a manner that represents generally
linear progress from the 2002 baseline
year to the attainment year.
b. Final Rule
The final rule requires a State to
submit an RFP plan along with its
attainment demonstration and SIP due
in April 2008 for any area for which the
State justifies an extension of the
attainment date beyond 2010. The RFP
plan must provide emission reductions
such that emissions in 2009 represent
generally linear progress from the 2002
baseline year to the attainment year.
Where the State justifies an extension of
the attainment deadline to 2014 or 2015,
the state must additionally provide
emission reductions such that emissions
in 2012 represent generally linear
progress from the 2002 baseline year to
the attainment year.
45
The RFP test uses inventories for the full year,
e.g. the year of 2009 or the year of 2012. EPA does
not specifically require that the relevant measures
be implemented by the beginning of the year, but
RFP inventories must reflect the fact that measures
that are implemented later in the year have
correspondingly less impact on the year’s annual
total emissions.
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If the State demonstrates that
attainment will occur by 2010 or earlier,
EPA will consider the attainment
demonstration to demonstrate
achievement of reasonable further
progress, and the State will not be
required to submit an additional RFP
plan for the area.
c. Comments and Responses
Comment:
For areas that demonstrate
attainment by 2015 without adopting
additional measures, a commenter
recommended that the attainment
demonstration be viewed as also
demonstrating that the area is achieving
RFP. The commenter therefore
recommended that the state not be
required to submit an RFP plan for such
an area.
Response:
A submittal that
demonstrates attainment at the latest
allowable date and does not address
interim air quality fails to show that the
path to attainment will yield interim
incremental air quality improvements.
States have ample opportunity to adopt
measures that would provide interim air
quality improvement long before 2015.
Indeed, as discussed elsewhere as part
of the discussion of attainment dates, a
submittal that only addresses 2015
would also fail the attainment
demonstration requirement, insofar as it
would not be addressing whether
attainment is as expeditious as
practicable, because the submittal
would fail to assess whether attainment
could be achieved earlier. Therefore,
irrespective of whether additional
measures are needed to attain by 2015,
the Clean Air Act mandates assessing
progress at reasonable interim dates as
well as mandating attainment.
4. Generally Linear Progress and
Associated Timeline
a. Background
The EPA proposed that states with
areas needing an extension of the
attainment deadline beyond 2010 would
be required to submit a plan
demonstrating that emissions would be
sufficiently reduced by 2009 to achieve
a generally linear incremental
improvement in air quality. The notice
of proposed rulemaking provided an
example calculation for an area with a
2013 attainment date, i.e. an area that
achieves attainment level emissions in
2012. (See section III.G.4.b.iv of the
proposal, 70 FR 66013.) In this example,
the 2009 emissions year represents 7/10
of the period extending from the
baseline year of 2002 to the 2012 year
of attainment level emissions.
Therefore, for this example, EPA’s
proposed requirement would be for this
area to achieve emission reductions by
2009 representing approximately 7/10 of
the emission reductions needed to attain
the standards. For states with areas
needing the attainment deadline
extended to 2014 or 2015, EPA
proposed to require achievement of
generally linear emission reductions at
two RFP milestone years—the 2009 and
2012 emission years.
The EPA received several comments
on various elements of its proposed
approach. Several commenters objected
to EPA’s proposed requirement to
achieve linear progress toward
attainment, asserting that EPA cannot
reasonably expect states to achieve a
significant amount of progress within a
short time after plan submittals are due.
Some commenters recommended
requiring a specific emission reduction
percentage, similar to the rate of
progress requirement for ozone. These
comments are addressed below.
b. Final Rule
The EPA is requiring States with areas
needing an extension of the attainment
deadline to submit RFP plans. These
plans must demonstrate that generally
linear reductions in emissions will
occur by 2009, i.e. that emissions in
2009 will be reduced to the extent
represented by a generally linear
progression from 2002 base year
emissions to attainment-level emissions.
For any area that needs an extension of
the attainment deadline to 2014 or 2015,
the State’s RFP plan would also need to
demonstrate that generally linear
reductions will be achieved in the 2012
emissions year as well.
c. Comments and Responses
Comment:
Several commenters
objected to EPA’s proposed requirement
that states demonstrate linear progress
toward attainment. For example, a
commenter stated that a ‘‘generally
linear reduction process may not be
practicable.’’ A commenter stated that it
‘‘agrees that areas should be able to take
credit for reductions from 2002 forward,
[but] EPA should allow for fewer
reductions (as opposed to linear
reductions) prior to 2008.’’
A commenter noted that EPA’s
‘‘proposed approach ignores several
important realities about PM NAAQS
implementation. First, * * * [n]ot until
SIP submittal in April 2008, some 6
years after the RFP baseline date, will
any local measures be finally adopted
and approved. Under [the example EPA
provided in its proposed rulemaking],
states will be required to play ‘catch-up’
by achieving 70 percent of the required
reductions in 2009. * * * Second, the
‘generally linear’ approach ignores that
EPA intends for states to rely in large
part on mobile source reductions and
reductions in NO
X
and SO
2
from CAIR
implementation to achieve attainment
in many areas. These measures fail a
‘generally linear’ test since most of the
reductions they provide will not be
realized until after 2009.’’ This
commenter continues that the
incremental reductions in emissions
required in the Clean Air Act need not
be equal increments, that the absence of
a specific statutorily mandated
increment (such as the 3 percent per
year requirement for ozone) allows EPA
to be more flexible and to rely more
heavily on later reductions. The
commenter also argues that EPA’s
proposal is more stringent than the
ozone RFP requirement, insofar as the
ozone RFP requirement provides for
averaging over 3 years. Similar
comments were submitted by other
commenters.
Another commenter supported EPA’s
proposal. This commenter supported
requiring demonstrations that areas
achieve emission reductions that will
yield incremental improvement in air
quality on a path toward expeditious
attainment.
Response:
The EPA believes that the
requirement for generally linear
reductions is reasonable because it
allows States to take credit for early
reductions achieved due to federal,
State, and local programs. We find that
it appropriately implements the RFP
requirement in the Clean Air Act. For
these reasons, EPA is finalizing the
requirement that RFP plans for areas
needing an attainment deadline
extension show generally linear
progress in reducing emissions from the
base year through the 2009 emissions
year. EPA is also requiring that areas
needing an attainment deadline
extension to 2014 or 2015 (i.e.
attainment level emissions projected to
start in 2013 or 2014) show generally
linear progress in reducing emissions
through the 2012 emissions year.
The commenters objecting to the
requirement for generally linear
progress appear to be assuming that
only minimal emission reductions can
be expected before 2008, so that a
requirement for generally linear
progress would require plans submitted
in 2008 to compensate by achieving
unrealistically high levels of emission
reductions. The EPA disagrees with this
assumption.
In fact, substantial emission
reductions have occurred in the past
few years and can be expected to occur
through the 2009 emissions year. The
EPA has promulgated significant mobile
source rules recently that will yield
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substantial benefits in the coming years,
and these benefits follow a series of
prior rules that provide a steady
progression of emission reductions as
newer, cleaner vehicles replace older,
dirtier vehicles. For utilities, significant
NO
X
reductions occurred in 2004 under
the NO
X
SIP call, and substantial SO
2
reductions are expected to occur under
the CAIR trading program prior to 2010
due to incentives for early reductions
and the banking of allowances.
The EPA has also promulgated many
other regulations that will reduce
particulate matter and particulate matter
precursor emissions before as well as
after 2009. States have also been
implementing a variety of measures.
With use of a 2002 baseline, the
assessment of RFP allows credit for
these measures. The following is a
partial list of the measures that have
been adopted and will contribute to
achieving generally linear reductions:
NO
X
SIP Call.
Tightened emission limits for new
gasoline and diesel vehicles.
Numerous regulations requiring
Maximum Achievable Control
Technology, including regulations for:
—Iron and steel plants, including coke
plants
—Industrial boilers
—Cement plants
—Lime plants
—Primary aluminum plants
Numerous consent decrees for
refineries.
Numerous consent decrees for
power plants.
The Clean Air Interstate Rule for
utilities.
Retrofitted controls on diesel
vehicles, and related programs for
reducing diesel vehicle emissions.
Closures of coke plants and other
facilities (and, from a national
perspective, replacement with cleaner
new facilities).
While different control measures
require various timelines for
implementation, EPA believes that
many of the additional measures that
states might adopt for attainment
planning purposes can be implemented
in a timely fashion for addressing RFP
requirements. Thus, EPA believes that
states can reasonably be expected to
assure that the combination of existing
measures and additional measures as
necessary will provide for generally
linear progress in reducing emissions.
Furthermore, particularly with respect
to the 2009 RFP milestone year, when
EPA evaluates whether the emission
levels in a state plan represent generally
linear progress, EPA will consider the
availability of measures that can be
implemented by 2009.
It is difficult to compare the
stringency of this RFP requirement to
the RFP requirement for ozone. The RFP
requirement for ozone measures one
form of progress that occurs after 3
years, and the requirement for PM
2.5
measures a different form of progress
that occurs after 7 years (and for some
areas also after 10 years). That is, the
ozone RFP requirement applies a fixed,
universally applicable emission
reduction percentage for one pollutant
(VOC), whereas EPA is defining the
PM
2.5
RFP requirement as an area-
specific combination of emission
reductions for multiple pollutants,
defined on the basis of each area’s
attainment demonstration.
The EPA believes that the Clean Air
Act mandates not merely eventual
attainment by 2015 but also that states
demonstrate that emissions are being
incrementally reduced in earlier years.
(As discussed elsewhere, states must
also demonstrate attainment by earlier
than 2015 if feasible.) The requirement
for RFP reflects Congressional intent
that areas make steady progress toward
attainment in the years before
attainment occurs, and states have
ample opportunity to assure that
reductions occur well before 2015.
Comment:
A commenter observes that
the PM
2.5
nonattainment areas in its
state also violate the ozone standard.
The commenter observes, ‘‘[i]n setting
plan requirements, U.S. EPA should
choose options that best facilitate
harmonization of fine particulate and
ozone control programs. This includes
using a fixed percentage of emission
reductions per year for reasonable
further progress (RFP). We recommend
the ozone RFP metric of three percent
annual emission reductions averaged
over three years.’’ Another commenter
also supports a more prescriptive RFP
requirement, and comments that ‘‘As
suggested by EPA, nonattainment areas
must be required to achieve ‘a fixed
percentage reduction of the emissions of
direct PM
2.5
and regulated PM
2.5
precursors and in specific milestone
years’ between the base year and the
attainment year proposed in the
attainment demonstration.’’ A third
commenter supported establishing a
requirement for a fixed emission
reduction percentage, set at ‘‘no less
than the 3 percent rate’’ in Section 182,
with the possibility of higher rates in
areas with more severe air quality
problems.
Other commenters prefer the
approach that EPA proposed. For
example one commenter states that it
agrees with EPA’s approach of using the
attainment demonstration to define the
parameters for determining what
constitutes RFP, and the commenter
supports the flexibility of EPA’s
proposed approach ‘‘rather than
requiring fixed linear percentage
reductions.’’ Regarding the proposed
option to require 3 percent per year
emission reductions for areas classified
as serious, some commenters
recommended against establishing
classifications and a fixed emission
reduction percentage for any area.
Response:
Requiring a fixed annual
emission reduction percentage would
impose a ‘‘one-size-fits-all’’ approach to
address a range of circumstances.
Requiring a fixed annual emission
reduction percentage would overstate
the reductions needed to achieve timely
attainment in some areas and would
understate the reductions needed to
achieve timely attainment in other
areas. The EPA believes that defining
the RFP requirement in terms of
achieving generally linear progress
toward the emission reductions needed
for timely attainment assures that each
area will achieve a steady rate of
progress most appropriate for the area to
achieve timely attainment.
The EPA recognizes that many areas
are nonattainment for both PM
2.5
and
ozone and that the control programs for
the two pollutants are sufficiently
intertwined that harmonization of
planning for meeting requirements
applicable to the two pollutants is
important. However, because the
statutory requirements set forth in
section 182 do not apply to PM
2.5
RFP
plans, EPA believes it is neither
necessary nor appropriate to impose
these requirements for PM
2.5
. Indeed,
given the multiple pollutants that
contribute to PM
2.5
and the variations
that exist in the nature and composition
of PM
2.5
across the country, EPA
believes that the PM
2.5
RFP
requirements for generally linear
reductions are better defined to reflect
these variations and thus better targeted
toward the emission reductions that in
each area can be expected to lead
toward timely attainment. Further, EPA
believes that application of a different
form of the RFP requirement does not
cause conflicts in implementation
planning for the two standards. For
example, reductions of NO
X
emissions
will generally reduce concentrations of
both ozone and PM
2.5
, and NO
X
emission reductions are creditable for
meeting both the ozone and the PM
2.5
RFP requirements.
An important distinction between
PM
2.5
and ozone is that fine particle
formation is in general a more complex
process, affected by both direct
emissions and numerous precursor
pollutants. The EPA does not believe
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that RFP targets for PM
2.5
should be the
same as those used for the ozone
implementation program, nor should
the same percentage reduction be used
for all PM
2.5
related pollutants. Instead,
EPA believes that RFP plans should
reflect an appropriate combination of
pollutant reductions that most
effectively provides for attainment.
Therefore, EPA has defined an RFP
requirement in which target emission
reductions are established in
conjunction with the area’s attainment
plan.
5. Geographic Coverage of Emissions
Sources
a. Background
PM
2.5
concentrations reflect a
combination of impacts over a wide
range of geographic scales. For some
components of PM
2.5
, observed
concentrations typically arise
predominantly from sources within the
nonattainment area. For other
components, PM
2.5
concentrations may
be influenced by sources across a broad
area extending outside the
nonattainment area. The EPA’s intent is
to define the RFP requirement in terms
of emissions reductions that can be
expected to provide generally linear
improvements in air quality in the
nonattainment area. For this purpose,
EPA continues to believe that RFP
requirements for PM
2.5
are best defined
such that states evaluate emissions of
each pollutant throughout the area in
which the emissions substantially
influence PM
2.5
concentrations in the
nonattainment area.
As described in the proposed
rulemaking, EPA expects each area’s
attainment demonstration to identify
many of the parameters used to define
the emission reductions that would
represent RFP. First, the attainment plan
will identify the pollutants that are
being reduced to achieve attainment.
Second, the attainment plan will
identify the amount of reduction of each
pollutant and the date by which
attainment can be achieved. This
information suffices to calculate a
baseline set of reductions to be achieved
by 2009 to provide for RFP. Third,
where a state chooses to achieve RFP by
reducing some pollutants earlier than
others, the attainment plan will provide
the information needed to assess
whether the intended set of reductions
can be expected to provide a
comparable level of air quality
improvement. Fourth, if the State
intends to include emissions sources
located outside the nonattainment area
in its RFP plan, the information
necessary to justify inclusion of such
sources will likely be found in the
attainment plan.
The EPA’s proposed rulemaking
identified several expectations regarding
regional versus local impacts. For
directly emitted PM
2.5
(including
organic and other carbonaceous
particles as well as miscellaneous
inorganic particles and including
condensable particulate matter), EPA
recognized that impacts are commonly
localized, and that direct emissions of
PM
2.5
outside the nonattainment area
should not be included in the RFP plan.
Conversely, EPA recognized the regional
nature of secondarily-formed sulfate and
nitrate, and proposed that states could
justify inclusion in the RFP plan of SO
2
and NO
X
emissions sources located
within 200 kilometers of the
nonattainment area.
The EPA recognizes that fine particles
travel over long distances, and that
distant emissions of SO
2
and NO
X
emissions can influence a
nonattainment area’s air quality. At the
same time, distant sources can be
expected to have less impact than
sources closer to the nonattainment
area. EPA’s procedures for assessing
RFP rely on a general assumption that
all the sources included in the
assessment have a comparable impact
per ton of emissions. For this reason, it
would be inappropriate to include
distant emission sources in the
assessment. Indeed, limiting the
consideration of SO
2
and NO
X
emissions to a 200 kilometer range is
intended to assure that only sources
with comparable impacts are included
in the assessment.
b. Final Policy
The policy for addressing direct PM
2.5
emissions in RFP plans remains
unchanged from the proposal: only
emissions from within the
nonattainment area may be included.
Conversely, for SO
2
and NO
X
, EPA
believes that states could be able to
justify considering not only all
emissions in the nonattainment area but
also emissions within a distance that
may be up to 200 kilometers from the
nonattainment area. States may also be
able to justify consideration of VOC and
ammonia emissions outside the
nonattainment area on a case-by-case
basis. As we explain more fully below
in responding to comments, in
situations where the state demonstrates
that VOCs are a significant contributor
to PM
2.5
concentrations in the area, it
may be appropriate to include VOC
emission sources within a distance of
up to 100 kilometers of the
nonattainment area. Given the
uncertainties regarding ammonia
emission inventories and the effects of
reducing ammonia, EPA is not
establishing a policy on this issue with
respect to ammonia. States that expect
to regulate ammonia should consult
with their regional offices to determine
appropriate approaches for those areas.
The justification for considering
emissions outside the nonattainment
area shall include justification of the
state’s recommended definition of the
area used in the RFP plan for each
pollutant.
The EPA received comments objecting
to the possibility that RFP inventories
for areas outside the nonattainment area
could include selected sources
expecting substantial emission
reductions while excluding other nearby
sources expecting emission increases.
Based on its review of these comments,
EPA is revising its approach for
considering regional emissions. If the
state justifies consideration of precursor
emissions for an area outside the
nonattainment area, EPA will expect
state RFP assessments to reflect
emissions changes from all sources in
this area. The State cannot include only
selected sources providing emission
reductions in the analysis. The
inventories for 2002, 2009, 2012 (where
applicable) and the attainment year
would all reflect the same source
domain (i.e. the same set of sources
except for the addition of any known
new sources or removal of known,
creditably and permanently shut down
sources).
In cases where the state justifies
consideration of emissions of specified
precursors from outside the
nonattainment area, the state must
provide separate information regarding
on-road mobile source emissions within
the nonattainment area for
transportation conformity purposes. The
EPA’s transportation conformity
regulations (40 CFR Part 93.102(b)) only
require conformity determinations in
nonattainment and maintenance areas,
and these regulations rely on SIP on-
road motor vehicle emission budgets
that address the designated boundary of
the nonattainment area. For this reason,
if the state addresses emissions outside
the nonattainment area for a pertinent
precursor (i.e. a precursor for which
mobile sources are significant, as
discussed in the May 6, 2005
transportation conformity rule on PM
2.5
precursors at 72 FR 24280), the on-road
mobile source component of the RFP
inventory will not satisfy the
requirements for establishing a SIP
budget for transportation conformity
purposes.
In such a case, the state must
supplement the RFP inventory with an
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inventory of onroad mobile source
emissions to be used to establish a
motor vehicle emissions budget for
transportation conformity purposes.
This inventory must address on-road
motor vehicle emissions that occur
within the designated nonattainment
area, must be provided for the same
milestone year or years as the RFP
demonstration (i.e. 2009 and 2012 as
applicable), and must satisfy other
applicable requirements of the
transportation conformity regulations.
So long as the state provides this
separate emissions budget EPA believes
that this approach will optimally
address both the RFP and the
transportation conformity provisions of
the Act.
The EPA is restricting the geographic
area for RFP assessments to include
only areas within the state or states
represented in the nonattainment area.
For a single state nonattainment area,
only emissions within that state would
be considered, even if other states may
be within 200 kilometers of the
nonattainment area. For multi-state
nonattainment areas, only regions
within states represented in the
nonattainment area shall be included in
the RFP assessment. This restriction is
intended to address commenters’
concerns about the enforceability of
emission reductions included in the
RFP assessment and helps assure
accountability for these reductions. This
topic is discussed further in the
discussion below about multi-state
nonattainment areas.
The EPA is retaining the approach
that RFP assessments may not include
direct PM
2.5
emissions from sources
outside the nonattainment area. If a
State regulates VOC or ammonia
emissions as part of its attainment
strategy, the RFP plan must include
emissions of these pollutants. In the
event that a State technical
demonstration indicates that emissions
of VOC or ammonia from sources
outside the nonattainment area
contribute significantly to PM
2.5
concentrations in the nonattainment
area, EPA will consider on a case-by-
case basis whether it would be
appropriate to include emissions from
such sources in the RFP plan.
c. Comments and Responses
The EPA received numerous
comments on its proposal regarding
how regional versus local impacts
would be addressed. Multiple
commenters objected to EPA’s proposal
that states could consider sources
reducing emissions but ignore
neighboring sources increasing
emissions. Other commenters
recommended that EPA support
granting credit for reductions of direct
PM
2.5
emissions that occur outside
nonattainment areas. A few commenters
also recommended different treatment
of selected pollutants.
Comment:
Several commenters object
to the methods by which EPA proposed
to account for reductions outside the
nonattainment area. According to a set
of commenters, if indeed sources
outside the nonattainment area
contribute to nonattainment, ‘‘then EPA
cannot lawfully or rationally allow the
state to claim RFP credit from a single
source’s reductions without including
in the baseline emissions from all
sources (mobile, area and stationary)
within the same distance from the
nonattainment area, and without
calculating the impacts of increases and
decreases in such emissions on RFP.
Viewing reductions from a single
‘outside the area’ source in isolation
will invariably provide an incomplete
and inaccurate picture of the actual
increase or decrease in emissions
contribution to the nonattainment area
from all ‘outside the area’ sources.
Moreover, EPA’s proposal creates
numerous opportunities to game and
undermine the system. By allowing
nonattainment areas to rely on RFP
reductions made outside the
nonattainment area, the proposed rule
strays from the Act’s focus on achieving
emissions reductions from sources
within the nonattainment area.’’
Another commenter insisted that states
should not be allowed to consider
emissions from sources outside the area
unless they can demonstrate the impacts
of these sources on nonattainment area
concentrations.
In addition, a commenter objects to
consideration only of sources that are
reducing emissions and recommends
that EPA allow credit for upwind source
reductions only ‘‘on the condition that
all other major sources in the 200
kilometer boundary are also not allowed
to increase emissions.’’ Another
commenter supports an option which
states would only consider emissions
within the nonattainment area,
observing that to consider emissions
outside the nonattainment area would
be difficult to administer and might
inappropriately ‘‘dilute the reductions
needed in the nonattainment area.’’ This
commenter also observes that a 200
kilometer limit does not include much
of the emissions that yield long range
transport. Another commenter supports
crediting reductions outside the
nonattainment area but requests that
EPA define the area to be considered.
Response:
The EPA agrees that
examining emissions reductions of only
selected sources outside the
nonattainment area gives an inaccurate
assessment of the progress that an area
is making. For example, if a state took
credit for emission reductions at Source
A but ignored equal emission increases
at neighboring Source B, the state would
claim emission reductions in its RFP
plan when in fact no net emission
reductions had occurred.
The commenters suggest various
remedies for this problem. One
suggestion is to include all sources
within the area that is used. Another
suggestion is to allow no consideration
of emissions outside the nonattainment
area. Yet another suggestion is to allow
consideration of selected sources so
long as other sources do not increase
emissions.
The EPA is adopting the first of these
suggestions: for the pertinent area
outside the nonattainment area, the RFP
assessment must include emissions (for
all years evaluated) for all sources. The
EPA believes that inclusion of all
sources is needed to ensure that the RFP
plan reflects the actual net emissions
changes that are occurring in the
relevant area.
In cases where the state justifies
consideration of emissions of specified
precursors from outside the
nonattainment area, EPA is accepting
the recommendation of various
commenters that the inventories of these
precursors used for RFP purposes shall
include mobile source emissions as well
as stationary and area source emissions.
However, in cases where onroad mobile
source emissions are significant and are
therefore included, the state would need
to submit additional information for
transportation conformity purposes. As
discussed above, in accordance with
existing transportation conformity
regulations (40 CFR Part 93), the SIP’s
motor vehicle emissions budget(s) must
reflect an emissions inventory of on-
road mobile source emissions for the
nonattainment area. Consequently, in
these cases, the state would need to
supplement its RFP inventory with
information identifying the inventory of
on-road mobile source emissions within
the nonattainment area for the pertinent
precursor(s) for the applicable year or
years (i.e. 2009 and potentially 2012) to
be used to establish a motor vehicle
emissions budget for transportation
conformity purposes.
The relevant comments in general did
not address the dimensions of spatial
domain of the sources outside the
nonattainment area that would be used
in assessing RFP. EPA agrees with a
commenter urging, as a prerequisite to
including sources of the pertinent
pollutants outside the nonattainment
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area in the assessment, that states must
justify the inclusion of sources outside
the nonattainment area. This
justification would need to demonstrate
that these emissions have a substantial
impact on nonattainment concentrations
that warrants including these emissions
along with nonattainment area
emissions in assessing RFP. Another
commenter recommends that EPA
define the area to be included. Since the
demonstrations of impact are best done
by states, in conjunction with their
attainment planning, EPA intends to
allow States to justify the area to be
included, within distance limits
discussed above.
Comment:
Numerous commenters
recommend that EPA allow credit for
reductions of direct PM
2.5
emissions
outside the nonattainment area. Some of
these commenters also recommend that
EPA allow credit for mobile source
emission reductions outside the
nonattainment area. Other commenters
support EPA’s proposed approach, in
which states may justify considering
precursor emissions outside the
nonattainment area but must evaluate
direct PM
2.5
emissions based solely on
emissions within the nonattainment
area.
Response:
Under Section 107 of the
Clean Air Act, EPA is to designate
nonattainment areas that include areas
nearby to the violations that contribute
to the violations. Given the spatial scale
of the impacts of direct PM
2.5
emissions,
EPA believes that any direct PM
2.5
emission source that demonstrably
influences nonattainment area
violations (and thus would contribute to
these violations) would also be
considered to be nearby to the violations
for designation purposes. The EPA
believes that it has properly defined the
nonattainment areas to include all
nearby contributing sources.
Nevertheless, EPA asks anyone with
evidence that an additional source or
source area contributes to violations in
a nonattainment area to submit that
information to EPA and to recommend
incorporation of that source or source
area into the nonattainment area.
The EPA has commented on
consideration of mobile source
emissions above. For direct PM
2.5
emissions, EPA believes that the
nonattainment area properly defines the
area of consideration, and emissions
from mobile sources outside the
nonattainment area, like emissions from
stationary sources outside the
nonattainment area, should not be
considered. For precursors for which
consideration of emissions outside the
nonattainment area is justified, the
applicable inventories would include
emissions from all sources including
mobile sources as well as stationary
sources.
Comment:
A commenter states that
‘‘RFP credits for VOC should be granted
for reductions achieved within the
nonattainment area as well as [within]
geographical limits outside of the
nonattainment area.’’ This commenter
supports consistency with the ozone
policy, which allows credit for NO
X
reductions within 200 kilometers and
VOC reductions within 100 kilometers
of the nonattainment area. Another
commenter makes similar comments
regarding VOC and comments that ‘‘[a]s
the science and understanding of PM
2.5
formation increases, EPA must revisit
the 200 kilometer parameter and
develop a possible proposal for
ammonia.’’
Response:
Conceptually, EPA agrees
that in areas where anthropogenic VOC
emissions outside the nonattainment
area are shown to be a significant
contributor to nonattainment area PM
2.5
concentrations, presumably by
formation of organic particles that
influence nonattainment area
concentrations, reduction of these VOC
emissions could help improve air
quality in the nonattainment area.
Therefore, EPA is revising its policy to
accommodate consideration of these
potential impacts. The EPA believes that
as the impacts of anthropogenic VOC on
PM
2.5
concentrations are better
understood, it may in some cases be
appropriate to consider sources outside
the nonattainment area in RFP plans if
the impacts from such sources can be
properly quantified and justified.
Nevertheless, EPA must highlight the
technical challenges involved in
assessing the impacts of VOC emission
reductions. First, it is essential that the
impacts of secondary organic particle
formation from anthropogenic VOC
emissions be differentiated from the
impacts caused by biogenic VOC
emissions and from the impacts of
direct organic particle emissions.
Second, the process of organic particle
formation is highly complex, and
currently available atmospheric models
typically perform poorly in assessing
the mass of particles thus formed. Third,
the distance range of impacts, and to be
more precise the distance range over
which source impacts are comparable, is
especially uncertain. While the distance
range for organic particle formation is
not necessarily the same as for the
influence of VOC on ozone formation, it
may be appropriate to include sources
within 100 kilometers of the
nonattainment area for both purposes,
as the commenter recommended.
However, any state wishing to include
such sources outside the nonattainment
area must justify the distance range that
is appropriate for the area.
The EPA is not prepared at this time
to establish generally applicable
guidance with respect to how RFP plans
should address ammonia in cases where
that precursor is found to be significant.
States that expect to regulate ammonia
emissions should consult their regional
office regarding appropriate approaches
for their particular areas.
Finally, EPA agrees with the
commenter that EPA should revisit the
range of issues regarding geographic
distances of impacts as more
information and understanding become
available.
6. Pollutants To Be Addressed in the
RFP Plan
a. Background
A number of commenters appeared to
be confused by the discussion in the
notice of proposed rulemaking regarding
the pollutants to be included in the RFP
assessment. The EPA proposed that the
attainment demonstration would
provide the key parameters of the RFP
demonstration, and that the list of
pollutants to be addressed in the RFP
demonstration would match the list of
pollutants regulated as part of the
attainment demonstration. However, the
notice of proposed rulemaking also
suggested that the presumptions
regarding whether different pollutants
are to be regulated under NSR and
RACM (including RACT) would also
apply to RFP. This led some
commenters to recommend different
treatment of specific pollutants.
In fact, the presumptions of
applicability that EPA is promulgating
for RACM are not germane to RFP. The
pollutant coverage of RFP assessments
is determined on an area-specific basis
according to each area’s attainment
demonstration, and EPA need not
establish presumptions as to what
pollutants are included in the RFP
assessment. For example, if a state
includes no NO
X
emission reductions in
its attainment plan, then the RFP plan
would not include NO
X
, irrespective of
whether the (uncontrolled) NO
X
emissions contribute significantly to the
areas PM
2.5
concentrations.
The contrast between establishment of
presumptions for RACM and having no
such presumptions for RFP (or for
attainment demonstrations) reflects
differences in regulatory context. For
RACM, at issue is whether the impact of
the pollutant is sufficient to warrant full
implementation of the RACM
requirements. In contrast, for RFP (as for
attainment plans), EPA is establishing
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an overall progress requirement that
may be met by applying various control
levels to various pollutants, so long as
overall emission reductions are
adequate. Indeed, if the state chooses
not to control a particular pollutant in
its attainment plan, then the
presumption is that that pollutant
would not be reduced in the RFP plan
either. Furthermore, states have the
flexibility to meet the overall progress
with any adequate combination of
control of relevant pollutants, regardless
of the significance or insignificance of
these pollutants’ impacts. For these
reasons, EPA is making no
presumptions as to what pollutants will
be included in RFP plans.
b. Final Policy
As proposed, the pollutants to be
addressed in the RFP plan are those
pollutants that are subject to control
measures in the attainment plan.
c. Comments and Responses
Comment:
A commenter states that
‘‘VOC should be considered a
presumptive PM
2.5
precursor.’’ Another
commenter recommends presuming that
VOC and ammonia are included in the
RFP plan.
Response:
The EPA’s approach to RFP
does not rely on presumptions as to
whether a pollutant does or does not
warrant regulation as a precursor.
Instead, pollutants are to be included or
excluded according to whether the
attainment demonstration includes
emission controls for the pollutant that
yield quantitative air quality benefits.
Thus, irrespective of the presumptions
applicable to RACM, the RFP plan
would not include VOC unless the
attainment plan reflects air quality
improvements from VOC emission
controls. The challenges of addressing
VOC as part of an RFP plan were
discussed earlier in this section.
Similarly, ammonia would not be
included in the RFP plan if the
attainment plan does not regulate
ammonia emissions.
7. Equivalent Air Quality Improvement
a. Background
The EPA proposed that states could
use alternative combinations of various
types of emission control programs to
meet RFP requirements if the alternative
would be expected provide air quality
improvements that are approximately
equivalent to those of the benchmark
emission reductions. Some control
programs for some pollutants can be
implemented more quickly than other
control programs. EPA believes that it is
unnecessary to require that all
pollutants be reduced at the same rate
or by the same fraction of the ultimate
attainment plan reductions. The EPA
believes instead that the states should
have flexibility to ‘‘mix and match’’
control strategies, so long as they
provide a demonstration that the
adopted approach can be expected to
yield approximately the same air quality
progress as an approach in which the
state achieves an identical fraction of
the attainment strategy for all pollutants
by the RFP milestone date.
The notice of proposed rulemaking
presented examples of the assessment of
RFP, illustrating EPA’s recommended
approach for establishing a benchmark
set of emission reductions and
illustrating EPA’s recommended
procedures for whether modified
approaches that control some pollutants
earlier than other pollutants may be
considered equivalent. While not
repeated here, the examples remain
appropriate for describing the approach
included in the final rule. (See 70 FR
66012–66013).
Most commenters supported EPA’s
proposal to allow alternative
combinations of control that can be
shown by simple means to be
equivalent. A set of commenters
objected to this approach, given the
uncertainties involved in the
equivalency assessment. Nevertheless,
for this aspect of RFP policy, EPA’s final
policy reflects the policy that it
proposed.
b. Final Policy
The EPA is adopting an approach that
establishes a benchmark level of
controls but allows states the flexibility
to adopt any combination of controls of
the various pollutants that can be shown
to provide equivalent benefits using
procedures that EPA is recommending
(or at the State’s option, air quality
modeling). The first step is to determine
the ratio of the number of years from the
baseline year to the RFP review year
(e.g., the 7 years from 2002 to 2009)
divided by the number of years from the
baseline year to the year in which
attainment level emissions are achieved
(e.g. the 10 years from 2002 to 2012, for
an area with a 2013 attainment
deadline). The benchmark level of
controls is then determined by
multiplying this ratio times the level of
control being achieved for each
pollutant. For example, for an area with
an attainment deadline extended to
2013, the benchmark level of controls
would reflect
7
⁄10 of the emission
reductions of each pollutant that is
controlled in the attainment plan.
The equivalency process involves
consideration of the air quality benefits
for the emission reductions in the
alternative plan for each regulated
pollutant. In effect, the air quality
benefits for each pollutant are used as
weighting factors, such that pollutants
for which controls yield larger benefits
are weighted more heavily in
determining the adequacy of the
resulting plan. For each pollutant, the
first step is to find the ratio of the
emission reductions achieved by the
RFP milestone date (e.g. the emission
reductions achieved between 2002 and
2009) divided by the emission
reductions achieved by the attainment
date. The second step is to multiply this
ratio times the air quality improvement
attributable to full implementation in
the attainment year of the attainment
strategy relevant to that pollutant. The
third step is to add these pollutant-
specific results to obtain a total
estimated air quality benefit of the
alternative plan.
The air quality benefits of the
benchmark reductions are easier to
determine. The first step, inherent to
defining the benchmark reductions, is to
determine the ratio of the number of
years to the RFP review divided by the
number of years to attainment level
emissions (in the example above,
7
⁄10).
The second step is simply to multiply
this ratio times the quantity of air
quality improvement achieved by the
attainment plan. (Conceptually, the
calculations are the same as are done for
the alternative plan, but the
mathematics are simpler because one is
applying the same assumed fraction of
the attainment plan emission reductions
(e.g.
7
⁄10) for all pollutants, so that there
is no need to subdivide by pollutant.)
For each milestone date, any alternative
that provides estimated air quality
benefits by the RFP milestone date that
at a minimum are generally equivalent
to the estimated benefits of the
benchmark level of emission reductions
will be considered to satisfy RFP
requirements.
c. Comments and Responses
Comment:
A set of commenters argues
that the equivalency process is too
uncertain, and recommends instead that
states be required to achieve at least a
fixed percentage reduction for all
pollutants. The commenters cite the
uncertainties acknowledged by EPA,
including potential nonlinearity (i.e.
that a given percentage of an emission
reduction may yield a different
percentage of the related air quality
benefit). The commenters contrast EPA’s
willingness to accommodate these
uncertainties, for purposes of giving
states flexibility for alternate RFP plan
designs, with EPA’s unwillingness to
accommodate the uncertainties inherent
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in regulating ammonia emissions. The
commenters state that ‘‘Rather than
propose a standardized process for
coherently determining ‘equivalency,’
EPA embraces the possibility that States
will invent multiple and disparate
methodologies.’’ The commenters argue
that the need for certainty in achieving
emission reductions trumps the benefits
of state flexibility, not the other way
around. The commenters state that if
‘‘EPA decides nonetheless to accept
equivalency demonstrations, it should
at least * * * require States to conduct
dispersion modeling’’ to confirm
equivalency. The commenters further
find unlawful the fact that EPA would
allow ‘‘rough equivalency’’ rather than
full equivalency to the benchmark
approach. The commenters would
prefer that EPA required a fixed
percentage reduction of the emissions of
direct PM
2.5
emissions and of each
precursor.
Response:
The EPA believes that its
proposed approach satisfies the intent of
the RFP requirement, which is to make
ongoing, steady progress toward
attainment rather than backloading
control strategies. A requirement to
obtain at least a given percentage of
each of the pollutants that contribute to
PM
2.5
concentrations would impose an
inflexibility that EPA concludes is
unnecessary where not required by the
statute. The EPA proposed to require
that areas achieve emission reductions
that are generally linear, and a plan that
provides for rough equivalency to the
benchmark approach would indeed
provide generally linear reductions. In
response to commenters’ requests for a
standardized process for assessing
equivalency, EPA believes the process
outlined in the final rule is responsive
to this request. It is not clear whether
the fixed reduction percentage that
certain commenters recommended
would be an area-specific percentage
(such as EPA uses to define the
benchmark approach) or a universally
applicable percentage (such as 3 percent
per year). If the former, then EPA would
repeat the response above regarding
flexibility being consistent with the
Act’s requirements; if the latter, then
responses in III.6.4 regarding a fixed
reduction percentage apply. The EPA
believes that the procedures it is
establishing to assess equivalency are
adequate for assessing RFP and that
dispersion modeling need not be
required for this purpose.
8. Other RFP Issues
a. Multi-State Nonattainment Areas
As stated in the proposed rulemaking,
EPA seeks to ensure that nonattainment
areas that include more than one State
meet RFP requirements as a whole.
Some commenters expressed concern
about how one state’s submittal should
address emissions in other states,
including how the state might address
questions about the enforceability of
another state’s requirements.
The issues here resemble the issues
for attainment demonstrations. In that
context as well, EPA seeks plans that
reflect active consultation by the
affected states and provide a
combination of reductions that are
enforceable by the respective states that
collectively provide for attainment. The
active involvement of regional planning
organizations helps assure a collective
design of a plan with specific
requirements to be adopted by specific
states. Likewise for RFP, EPA would
expect states with multi-state
nonattainment areas to consult with
other involved states, to formulate a list
of the measures that they will adopt and
the measures that the other state(s) will
adopt, and then to adopt their list of
measures under the assumption that the
other state(s) will adopt their listed
measures. That is, each state would be
responsible for adopting and thereby
providing for enforcement of its list of
measures, and then that state and
ultimately EPA (at such time as the plan
is approved) would be responsible for
assuring compliance with the SIP
requirements.
In accordance with this view of RFP,
as is the case for attainment plans, EPA
expects states sharing a multi-state
nonattainment area to submit a common
assessment of whether RFP will occur.
As a default, if the assessment only
includes emissions within the
nonattainment area, then each state
would submit an assessment based on
emissions from the full nonattainment
area including portions of the area in
other states. If the assessment includes
precursor emissions from additional
area outside the nonattainment area,
then the states should have a common
rationale for the area included, and all
affected states would use the same
inventory of the same multi-state area
thus defined in assessing whether RFP
will occur. The EPA would judge such
submittals based on (1) whether the
overall projected emission reductions
will achieve RFP and (2) whether the
submitting state has adopted the
necessary enforceable measures to
assure that the reductions projected
within its boundaries will in fact occur.
As a point of clarification, even if a
state justifies consideration of emissions
outside the nonattainment area in its
RFP assessment, EPA intends that these
assessments not use emissions from
outside the state or states represented in
the nonattainment area. For single state
nonattainment areas, only emissions
within that state would be considered.
This will help assure accountability for
the emission reductions included in the
plan.
b. Tribal Areas
The EPA received no comments on its
proposed policy regarding RFP for tribal
areas, and EPA is finalizing the
proposed policy. Under its Tribal
Authority Rule (40 CFR 49.4), EPA
found that it was not appropriate to
apply SIP schedule requirements to
tribes. For similar reasons, EPA is not
requiring tribes to submit RFP plans.
Generally this exemption will have
limited if any impact on the
achievement of RFP by an area.
Nevertheless, consistent with its general
role in implementing programs for tribes
where ‘‘necessary and appropriate,’’
EPA will work with the affected tribes
and states to ensure that emissions on
tribal lands are addressed appropriately.
The EPA intends to ensure that areas
that include both state and tribal lands
will satisfy RFP on a collective basis,
similar to the policy applicable to multi-
state nonattainment areas.
9. Mid-Course Review
a. Background
The EPA proposed requiring mid-
course reviews on a case-by-case basis.
The proposal described a mid-course
review as a combination of reviews
aimed at assessing whether a
nonattainment area is or is not making
sufficient progress toward attainment of
the PM
2.5
standards. The proposal
described the mid-course review as
involving ‘‘three basic steps: (1)
Demonstrate whether the appropriate
emission limits and emission reduction
programs that were approved as part of
the original attainment demonstration
and SIP submittal were adopted and
implemented; (2) analyze available air
quality, meteorology, emissions and
modeling data and document relevant
findings; and (3) document conclusions
regarding whether progress toward
attainment is being made using a weight
of evidence determination.’’ (Cf. 70 FR
66010)
The EPA views mid-course review
requirements as part of a set of
requirements for implementing the
Clean Air Act requirements for
reasonable further progress. For areas
that demonstrate attainment by April 5,
2010, EPA believes that this attainment
demonstration also demonstrates that
reasonable further progress is being
achieved. For areas that demonstrate
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attainment after April 5, 2010, EPA is
requiring states to submit an RFP plan,
due on April 5, 2008, showing that
emissions in 2009 and, in some cases,
in 2012, will be sufficiently reduced to
provide generally linear progress toward
levels that are expected to yield
attainment. At issue here is how then to
conduct ongoing tracking of whether the
planned progress toward attainment is
in fact occurring. Subparts 2 (for ozone)
and 4 (for PM
10
) include explicit
requirements for ongoing milestone
tracking. Since Subpart 1 (applicable for
PM
2.5
) allows EPA flexibility in
determining how ongoing progress is to
be tracked, EPA may adopt other
approaches for achieving the necessary
assurances that ongoing progress toward
attainment is occurring.
Milestone reviews can be confounded
by changes in inventory methods (a
concern expressed by a commenter
particularly with respect to condensable
emissions) and involve lengthy delays
while inventories are compiled before
planning can begin. Other approaches
involving only air quality data reviews
also do not provide for timely planning,
insofar as such approaches involve
waiting for three years of air quality data
after implementation of controls before
planning can begin. The EPA believes
that a mid-course review provides the
most productive approach, in lieu of
establishing milestone tracking or other
requirements, to assure that reasonable
further progress in reducing emissions
is being achieved. For this reason EPA
proposed a requirement for mid-course
reviews.
The EPA proposed a process for
establishing and implementing mid-
course review. After the state submits an
attainment plan (due in April 2008),
EPA would evaluate whether a mid-
course review is warranted after
considering various factors including
factors identified in the proposal. The
EPA did not propose to conduct further
rulemaking on establishing this
requirement, but EPA proposed that
‘‘[w]here EPA finds that a MCR would
be required, the approval of the
[attainment] demonstration would be
contingent on a commitment from the
State to conduct the MCR.’’ The mid-
course review would then be due April
2010. The EPA’s proposal also stated
that ‘‘EPA would determine [based on
review of the mid-course review]
whether additional emissions
reductions are necessary,’’ so that states
would need to complete the mid-course
review ‘‘three or more years before the
applicable attainment date to ensure
that any additional controls that may be
needed can be adopted [in timely
fashion].’’ Finally, EPA stated ‘‘[i]f a
mid-course review will be required for
certain PM
2.5
nonattainment areas,
separate PM
2.5
mid-course review
guidance will be written to address the
specific requirements of PM
2.5
nonattainment areas.’’
The EPA received numerous
comments objecting to EPA’s proposed
approach. Several commenters noted
the inconsistency between requiring a
mid-course review in April 2010 versus
requiring a mid-course review due 3 or
more years before an attainment date of
2012 or earlier. Multiple commenters
objected to EPA requiring a mid-course
review only 2 years after the initial
attainment plan is due. A commenter
requested ‘‘nationally applicable
guidance on when an MCR would be
required and what it would need to
include.’’ No commenters supported
EPA’s timeline for mid-course reviews.
Based on the comments that EPA
received, EPA has reevaluated the
process for mid-course reviews. Upon
reevaluation, EPA shares many of the
concerns expressed by commenters
about the proposal. The proposal indeed
presents conflicting dates for submittal.
The EPA agrees that a deadline just 2
years after the initial SIP submittal is
too soon for states to conduct
meaningful analyses of whether areas
are making progress towards attainment.
This problem would be exacerbated by
the proposed process, in particular the
fact that states would not know to begin
work on a mid-course review until after
they had submitted their initial SIP and
after EPA had sufficiently reviewed the
submittal to determine the need for a
mid-course review. An early mid-course
review also would defeat one of the
purposes of the mid-course review,
which is to take advantage of advances
in the science and understanding of the
nature of condensables and other
components of PM
2.5
, to adjust plans to
be better targeted at solving problems.
For these reasons, EPA is significantly
revising its approach to mid-course
reviews as recommended by the
commenters. The EPA is establishing a
rule which provides more certainty to
the states as to applicability and content
of mid-course review requirements,
thereby avoiding the need for future
EPA rulemakings on the subject. The
EPA’s rule clearly does not require
states with early attainment dates to
conduct a mid-course review and would
clearly mandate a mid-course review
only for areas with later attainment
dates. The EPA’s final rule clarifies the
content of mid-course reviews and
provides for states to make decisions on
whether further controls are needed
rather than having EPA make this
determination. The mid-course review
shall include an updated modeled
attainment demonstration as well as a
review of the implementation of
measures in the April 2008 SIP and a
review of recent air quality data. The
EPA believes that all of these elements
are necessary and should be sufficient
for the state to identify whether
additional measures are needed to
achieve attainment by the attainment
date in the approved plan. The EPA
believes that states, not EPA, should
make the initial determination as to
whether additional measures are
needed, and EPA has designed its mid-
course review requirements to provide
for the states to make this
determination.
The EPA is promulgating a fixed date
of April 2011 as a date for submittal of
mid-course reviews for areas with
attainment dates in 2014 or 2015. This
fixed date will facilitate joint planning
for multiple areas to apply common
assumptions regarding regional
transport. This date also gives states
adequate notice for preparing these
reviews and adequate time after the
April 2008 submittal to incorporate new
information and understanding of PM
2.5
nonattainment problems to adjust
attainment strategies as appropriate.
The EPA is not requiring areas
demonstrating attainment by 2013 or
before to conduct a mid-course review.
Such areas plan to have attainment level
emissions by 2012, and EPA believes
that an April 2011 mid-course review
would not provide a timely
reassessment of such areas’ attainment
plans. Instead, EPA is clarifying that
mid-course reviews are only required
for areas that demonstrate a need for an
attainment date extension at least to
April 2014.
b. Final Rule
For each area with an approved
attainment date in 2014 or 2015, EPA is
requiring the state to submit a mid-
course review by April 2011. The mid-
course review shall include an updated
attainment demonstration as well as a
review of the implementation status of
measures included in the April 2008
submittal and a review of recent air
quality data. The state shall determine
whether additional measures are needed
for timely attainment, just as the state is
responsible for determining whether
additional measures are needed in the
April 2008 attainment demonstration,
subject to formal EPA SIP review. The
EPA is not requiring RFP milestone
reviews, and EPA is requiring mid-
course reviews for areas with
sufficiently extended attainment dates
in lieu of any other form of tracking
reasonable progress.
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c. Comments and Responses
Comment:
A number of commenters
objected to EPA’s proposed timeframe
that would have areas submit a mid-
course review only 2 years after the
initial SIP is due. They recommended,
instead, that areas with attainment dates
2 years or more beyond the first 5-year
period submit mid-course reviews 3
years after the SIPs are due (April 2011)
and every 3 years thereafter, if
necessary. Their reason for this
suggestion is that the timing of mid-
course review requirements needs to be
clearer and should allow adequate time
between plans and mid-course reviews
if they are to serve as meaningful
reviews.
Several commenters also noted an
inconsistency in the timing of mid-
course review requirements under
EPA’s proposal. The EPA proposed that
mid-course review submittals would be
due 5 years after the initial designation,
which for all the original designations
means 5 years after April 2005, i.e. April
2010. However, EPA also proposed that
mid-course reviews would be due 3
years before the attainment date, which
for areas with an April 2012 attainment
date means April 2009. The commenters
considered April 2009 for a mid-course
review submittal to be too soon after the
initial SIP submittal in April 2008,
arguing that EPA would not have had
time to review the 2008 SIP submittal,
and the states would not have time to
prepare a mid-course review by 2009.
Some of these commenters expressed a
view that EPA should not require mid-
course reviews earlier than 3 years after
the SIP submittal date.
Response:
The EPA agrees with these
comments. The EPA is remedying the
inconsistency in submittal dates by
establishing the single submittal due
date of April 2011 that was
recommended by the commenters. As
requested by commenters, EPA is also
clarifying the applicability of the mid-
course review requirement. The
requirement shall apply to areas with
attainment dates of 2014 or 2015; mid-
course reviews shall not be required for
areas that are expected to attain the
standards by 2013.
Comment:
A commenter supports
mid-course reviews as a means of
assuring that areas with longer-term
compliance dates are on track to attain
the NAAQS as expeditiously as
practicable.
Response:
The EPA agrees that mid-
course reviews can be a critical step in
assuring expeditious attainment for
areas with extended attainment dates.
Indeed, EPA is relying on mid-course
reviews rather than milestone reviews
or other forms of RFP tracking to serve
this purpose.
Comment:
A commenter
recommended eliminating mid-course
review requirements for any area with
less than seven years between SIP
submittal and attainment. The
commenter urged that EPA carefully
reconsider its overall timelines for PM
2.5
while considering the feasibility and
practical usefulness of the steps
required of States and emission sources.
Response:
The EPA agrees that the
proposed timeline potentially required
mid-course reviews in areas where such
reviews would not be warranted, and
the timeline did not provide the clarity
as to the applicability of the
requirement that states need to fulfill
their planning responsibilities. In
response, EPA is not requiring mid-
course reviews for areas demonstrating
attainment prior to 2014. For those areas
that cannot demonstrate that attainment
will occur prior to 2014, EPA has
streamlined the mid-course review
process so that the state bears
responsibility for making the initial
determination as to whether additional
measures are needed to achieve timely
attainment, rather than requiring
additional steps of EPA rulemaking and
initial findings by EPA as to the level of
controls needed in the state’s SIP. With
the revised timetable, states can be
assured of a meaningful mid-course
review effort that focuses on the areas
that particularly warrant such a review
and for which time is available for a
productive assessment of the need for
additional measures.
Comment:
One commenter stated that
the proposal that allows the Agency to
determine whether or not a State needs
to submit a mid-course review with
their attainment demonstration on a
case-by-case basis lacks sufficient
information. Since these attainment
demonstrations must meet rigorous
criteria, and require substantial work by
the States, the commenter is concerned
that the proposal neglects to outline the
criteria EPA will use to make the case-
by-case mid-course review
determinations. The commenter asks
that EPA provide the States with
nationally applicable guidance on when
an MCR would be required and what it
would need to include.
Response:
The EPA agrees with this
comment. In particular, EPA agrees that
establishing clear criteria for
applicability and content of a mid-
course review requirement will provide
states the opportunity to plan for these
reviews and conduct appropriate
reviews in a timely fashion. Therefore,
this final rule is establishing specific
criteria for the applicability of the mid-
course review requirement, namely that
a mid-course review shall be conducted
for any area that cannot demonstrate
attainment before 2014. This final rule
is also identifying the necessary
elements of this mid-course review, i.e.
a review of the implementation of
measures in the 2008 SIP, and review of
recent air quality data, and an updated
modeled attainment demonstration.
H. Contingency Measures
a. Background
Under subpart 1 of the CAA, all PM
2.5
nonattainment areas must include in
their SIPs contingency measures
consistent with section 172(c)(9).
Contingency measures are additional
control measures to be implemented in
the event that an area fails to meet RFP
or fails to attain the standards by its
attainment date. These contingency
measures must be fully adopted rules or
control measures that are ready to be
implemented quickly upon failure to
meet RFP or failure of the area to meet
the standard by its attainment date. The
preamble to the proposal stated that the
SIP should contain trigger mechanisms
for the contingency measures, specify a
schedule for implementation, and
indicate that the measures will be
implemented without significant further
action by the State or by EPA. The
contingency measures should consist of
other control measures for the area that
are not included in the control strategy
for the SIP.
The April 16, 1992 General Preamble
provided the following guidance:
‘‘States must show that their
contingency measures can be
implemented without further action on
their part and with no additional
rulemaking actions such as public
hearings or legislative review. In
general, EPA will expect all actions
needed to affect full implementation of
the measures to occur within 60 days
after EPA notifies the State of its
failure.’’ (57 FR at 13512.) This could
include Federal measures and local
measures already scheduled for
implementation, as explained below.
The EPA has approved numerous SIPs
under this interpretation—i.e., that use
as contingency measures one or more
Federal or local measures that are in
place and provide reductions that are in
excess of the reductions required by the
attainment demonstration or RFP plan.
(62 FR 15844, April 3, 1997; 62 FR
66279, December 18, 1997; 66 FR 30811,
June 8, 2001; 66 FR 586 and 66 FR 634,
January 3, 2001.) The key is that the
statute requires that contingency
measures provide for additional
emission reductions that are not relied
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on for RFP or attainment and that are
not included in the demonstration. The
purpose is to provide a cushion while
the plan is being revised to meet the
missed milestone. In other words,
contingency measures are intended to
achieve reductions over and beyond
those relied on in the attainment and
RFP demonstrations. Nothing in the
statute precludes a State from
implementing such measures before
they are triggered. In fact, a recent court
ruling upheld contingency measures
that were previously required and
implemented where they were in excess
of the attainment demonstration and
RFP SIP.
See LEAN
v.
EPA
, 382 F.3d
575, 5th Circuit., 2004.
One basis EPA recommends for
determining the level of reductions
associated with contingency measures is
the amount of actual PM
2.5
emissions
reductions required by the control
strategy for the SIP to attain the
standards. The contingency measures
are to be implemented in the event that
the area does not meet RFP, or attain the
standards by the attainment date, and
should represent a portion of the actual
emissions reductions necessary to bring
about attainment in area. Therefore, the
emissions reductions anticipated by the
contingency measures should be equal
to approximately 1 year’s worth of
emissions reductions necessary to
achieve RFP for the area.
As stated previously, EPA believes
that contingency measures should
consist of other available control
measures beyond those required to
attain the standards, and may go beyond
those measures considered to be RACM
for the area. It is important, however,
that States make decisions concerning
contingency measures in conjunction
with their determination of RACM for
the area, and that all available measures
needed in order to demonstrate
attainment of the standards must be
considered first; all remaining measures
should then be considered as candidates
for contingency measures. It is
important not to allow contingency
measures to counteract the development
of an adequate control strategy
demonstration.
The preamble to the proposal stated
that contingency measures must be
implemented without ‘‘significant
further action’’ after EPA determines
that the area has either failed to meet
RFP, or has failed to attain the standard
by its attainment date. The purpose of
the contingency measure provision is to
ensure that corrective measures are put
in place automatically at the time that
EPA makes its determination that an
area has either failed to meet RFP or
failed to meet the standard by its
attainment date. The EPA is required to
determine within 90 days after receiving
a State’s RFP demonstration, and within
6 months after the attainment date for
an area, whether these requirements
have been met. The consequences for
states which fail to attain or to meet RFP
are described in section 179 of the CAA.
2. Final Rule
The final rule includes regulatory text
for contingency measures and maintains
the overall policy approach as described
in the preamble to the proposal. The key
requirements associated with
contingency measures are:
—Contingency measures must be fully
adopted rules or control measures that
are ready to be implemented quickly
upon failure to meet RFP or failure of
the area to meet the standard by its
attainment date.
—The SIP should contain trigger
mechanisms for the contingency
measures, specify a schedule for
implementation, and indicate that the
measures will be implemented
without further action by the State or
by EPA.
—The contingency measures should
consist of other control measures for
the area that are not included in the
control strategy for the SIP.
—The measures should provide for
emission reductions equivalent to
about 1 year of reductions needed for
RFP, based on the overall level of
reductions needed to demonstrate
attainment divided by the number of
years from the 2002 base year to the
attainment year. Contingency
measures are those measures that
would not be included in the
attainment strategy for various
reasons; for example, they may not be
as economically feasible as other
measures that are considered to be
RACM, or it may not be possible to
implement the measures soon enough
to advance the attainment date (e.g.
federal mobile source measures based
on the incremental turnover of the
motor vehicle fleet each year).
3. Comments and Responses
Comment:
Several comments were
received concerning the requirement for
contingency measures under section
172(c)(9). The proposal indicated that
contingency measures adopted as part of
the State plan are to be equal to
approximately 1 year’s worth of
emissions reductions necessary to
achieve RFP, as determined by the
attainment demonstration for the area.
One commenter indicates that this
amount of reductions for contingency
measures may be excessive in some
cases. The commenter stated that States
should be allowed to demonstrate
appropriate amount of reductions for
contingency measures in each area
based on the degree of the PM
2.5
nonattainment area problem and the
progression of emission reductions
planned for the area as a part of the SIP.
Response:
The EPA agrees that the
CAA does not include the specific level
of emission reductions that must be
adopted to meet the contingency
measures requirement under section
172(c)(9). One possible interpretation of
the CAA would assume that
contingency measures should be in
place in the event that all of the State’s
measures fail to produce their expected
emission reductions. Under this
scenario, the State theoretically would
be required to adopt sufficient
contingency measures to make up for
the entire short fall. In other words, the
State would have to adopt ‘‘double’’ the
measures required to satisfy the
applicable emissions reduction
requirements.
The EPA believes that this scenario
would be highly unlikely and that this
interpretation would be an unreasonable
requirement. The adoption of double the
measures needed for attainment would
be difficult for States. Therefore, the
EPA believes that it is reasonable that
contingency measures should, at a
minimum, ensure that an appropriate
level of emissions reduction progress
continues to be made if attainment or
RFP is not achieved, or if an area fails
to attain the standard by its statutory
attainment date and additional planning
is needed by the State. The EPA believes
that the contingency measures adopted
by the State for the affected area should
represent a portion of the actual
emissions reductions necessary to bring
about attainment in the area. Therefore,
EPA believes that it is reasonable to
require states to adopt contingency
measures equal to approximately 1
year’s worth of emissions reductions
necessary to achieve RFP for the area.
Comment:
One commenter claimed
that EPA incorrectly quoted the CAA as
requiring SIPs to provide for
implementation of contingency
measures upon an attainment or RFP
failure, without ‘‘significant’’ further
action by the State or EPA. The
commenter stated that section 172(c)(9)
does not contain the word ‘‘significant.’’
The CAA requires that contingency
measures take effect ‘‘without further
action’’ by the State or EPA.
Response:
The EPA agrees with the
commenter that the general
requirements for attainment plans
specified under section 172(c)(9) State
that each plan must contain additional
measures that will take effect without
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‘further action’ by the State or EPA if an
area either fails to make RFP or fails to
attain the standard by the applicable
attainment date. Section 51.1012 of the
final rule describes the contingency
measures requirement and does not
include the word ‘‘significant.’’
However, as a matter of practicality
states need to take minimal steps to
make contingency measures effective
and alert the affected public that the
measures are in force. Thus, EPA has
indicated based on conclusions first
made in the 1992 General Preamble that
states should complete all of these
administrative steps within 60 days and
that all regulatory steps be completed
before SIP submission.
Comment:
The commenter further
states that EPA is wrong in asserting
that contingency measures can include
Federal measures and local measures
already scheduled for implementation,
or previously implemented measures
that provide ‘excess’ reductions. The
CAA requires contingency measures to
consist of controls ‘to be undertaken if ’
the area fails to meet attainment or RFP.
The commenter states that this language
clearly states that such measures are to
be new measures that will be
undertaken upon the triggering event
specifically to address RFP or failure to
attain, not measures already in place, or
measures required for other reasons.
Further, the commenter claims that
EPA can not rationally refer to any
reductions prior to an attainment or RFP
failure as ‘excess’ when total reductions
in the area in fact prove insufficient to
meet attainment RFP. The commenter
states that EPA cites a 5th Circuit case
as support, but the commenter
respectfully submits that the case was
incorrectly decided on this issue for the
aforementioned reasons.
Response:
In response to comments
claiming that EPA is wrong in asserting
that contingency measures can include
Federal measures and local measures
already scheduled for implementation,
or previously implemented measures
that provide ‘excess’ reductions, as
stated previously, the EPA has approved
numerous SIPs under this
interpretation. The statute requires that
contingency measures provide for
additional emission reductions that are
not relied on for RFP or attainment and
that are included in the attainment
demonstration for the area. These
measures are intended to provide a
‘‘cushion’’ in terms of emissions
reductions for the area while the State
is revising the SIP for the area due to the
failure to show RFP or attain. In other
words, contingency measures are
intended to achieve reductions over and
beyond those relied on in the attainment
and RFP demonstrations. Nothing in the
statute precludes a State from
implementing such measures before
they are triggered.
As noted above, EPA’s General
Preamble interpreted the control
measure requirements of sections
172(c)(9) and 182(c)(9) to allow
nonattainment areas to implement their
contingency measures early. 57 FR
13498, 13511 (April 16, 1992). The EPA
has applied this interpretation in
rulemakings. See, for example, 67 FR
6,590, 6,591–92 (September 26, 2002).
See also rulemakings cited in the
Background section, above. As set forth
above, the Fifth Circuit has upheld
EPA’s interpretation.
Louisiana
Environmental Action Network
v.
EPA,
382 F.3d 575 (Fifth Cir. 2004). (‘‘
LEAN
’’)
Commenters have not provided a basis
for concluding that the Fifth Circuit in
the
LEAN
case wrongly interpreted the
CAA.
Commenters contend that the
language in the CAA regarding
contingency measure controls ‘‘to be
undertaken’’ requires measures not
already in place or required for other
reasons. The Fifth Circuit disagreed,
finding that the terms in section
172(c)(9)—‘‘to be undertaken’’ and ‘‘to
take effect’’—were ambiguous, and
finding persuasive EPA’s interpretation
that this language allows measures
already in place or otherwise required.
The Court held:
‘‘Here, the EPA’s allowance of early
reductions to be used as contingency
measures comports with a primary purpose
of the CAA—the aim of ensuring that
nonattainment areas reach NAAQS
compliance in an efficient manner—and
necessary requirements of the CAA.’’ 382
F.3d at 583.
The Court further found that ‘‘By
utilizing contingency measures early,
the contingency measures ensured that
‘an appropriate level of emissions
reduction progress’ would be
implemented while the State ‘adopt[ed]
newly required measures resulting from
the bump-up to a higher classification.’’
[citing the General Preamble].
Id.
In addition, the Court agreed with
EPA that ‘‘early reductions are
necessary in order to create an incentive
for nonattainment areas to implement
‘all reasonably available control
measures as expeditiously as
practicable’ ’’ in accordance with section
172(c)(1) of the CAA. Thus the Court
concluded that it would be ‘‘illogical to
penalize nonattainment areas that are
taking extra steps, such as implementing
contingency measures prior to a
deadline, to comport with the CAA’s
mandate that such states achieve
NAAQS compliance as ‘expeditiously as
practicable.’ ’’
Id.
at 583–584.
The Fifth Circuit also endorsed the
concept of ‘‘excess’’ reductions, noting
that the reductions credits at issue in
that case, ‘‘although already
implemented, are in effect set aside, ‘to
be applied in the event that attainment
is [not] achieved’ and such reduction
credits ‘are not available for any other
use.’ [citations omitted]. The setting
aside of a continuing, surplus emissions
reduction fits neatly within the CAA’s
requirement that a necessary element of
a contingency measure is that it must
‘take effect without further action by the
State or [EPA]’.’’ The Court concluded
that ‘‘the early activation of continuing
contingency measures is consistent with
the purpose and requirements of the
CAA statute.’’ Id. at 584.
Thus, EPA’s approval of early
implemented contingency measures is
consistent with the CAA, as well as with
EPA guidance. For example, EPA has
consistently taken the position that
ozone nonattainment areas classified
moderate and above must include
sufficient contingency measures so that
‘‘upon implementation of such
measures, additional emissions
reductions of up to 3 percent of the
emissions in the adjusted base year
inventory (or such lesser percentage that
will cure the identified failure) would
be achieved in the year following the
year in which the failure has been
identified.’’ 57 FR at 13511 (EPA’s
General Preamble). Thus the
contingency measures are supposed to
ensure that progress towards attainment
will occur while the relevant State
adopts whatever additional controls
may be necessary to correct a shortfall
in emissions reductions.
Id.
The EPA
has historically allowed early
reductions—that is, reductions achieved
before the contingency measure is
‘‘triggered’’—to be used as contingency
measures. See also August 13, 1993
Memorandum from G.T. Helms: Early
Implementation of Contingency
Measures for Ozone and Carbon
Monoxide (CO) Nonattainment Areas).
The commenter’s argument that
emission reductions cannot be valid
contingency measures if they are
otherwise required is also misplaced. A
State must have the legal authority to
require whatever reductions it may
require as a contingency measure. As
EPA has previously stated, ‘‘all
contingency measures must be fully
adopted rules or measures.’’ 62 FR
15844, 15846 (April 3, 1997). The fact
that the State or Federal government has
already exercised that authority is
irrelevant because, as noted above,
contingency measures must ‘‘take effect
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without further action by the State or
[EPA].’’ Section 172(c)(9). Thus, by
definition, the State necessarily will
have already exercised its legal
authority to require reductions as a
contingency measure before the measure
is triggered. It does not matter whether
or not a specific contingency measure is
already required by law, as long as the
emissions reductions that will result
from that contingency measure have not
been accounted for in the attainment
and reasonable further progress
demonstrations. If the reductions from
the contingency measure are not
available for any other use, then they are
surplus that is set aside in the event
reasonable further progress or
attainment is not achieved.
A key element of a valid contingency
measure reduction is that the State may
not use the reduction in its attainment
or reasonable further progress
demonstrations if it is already using the
reduction as a contingency measure.
Those demonstrations must account for
the actual emissions reductions that will
make reasonable further progress
towards, and achieve attainment of the
NAAQS in the absence of contingency
measures.
I. Transportation Conformity
Transportation conformity is required
under CAA section 176(c) (42 U.S.C.
7506(c)) to ensure that Federally
supported highway and transit project
activities are consistent with (‘‘conform
to’’) the purpose of the SIP. Conformity
currently applies to areas that are
designated nonattainment, and those
redesignated to attainment after 1990
(‘‘maintenance areas’’ with plans
developed under CAA section 175A) for
the following transportation-related
criteria pollutants: ozone, particulate
matter (PM
2.5
and PM
10
), carbon
monoxide (CO), and nitrogen dioxide
(NO
2
). Conformity to the purpose of the
SIP means that transportation activities
will not cause new air quality
violations, worsen existing violations, or
delay timely attainment of the relevant
NAAQS (or ‘‘standards’’).
The final PM
2.5
implementation rule
does not contain any revisions to the
transportation conformity regulation.
The EPA addressed the transportation
conformity requirements that apply in
PM
2.5
nonattainment and maintenance
areas in three separate rulemakings as
described below.
First, on July 1, 2004, EPA published
a final rule (69 FR 40004) that addressed
the majority of requirements that apply
in PM
2.5
areas including:
Regional conformity tests to be used
in conformity determinations both
before and after SIPs are submitted and
motor vehicle emissions budgets are
found adequate or are approved;
Consideration of direct PM
2.5
emissions in regional emissions
analyses;
Consideration of re-entrained road
dust in PM
2.5
regional emissions
analyses;
Consideration of transportation
construction-related fugitive dust in
PM
2.5
regional emissions analyses; and
Compliance with PM
2.5
SIP control
measures.
Then on May 6, 2005, EPA
promulgated a final rule (70 FR 24280)
that specified the transportation-related
PM
2.5
precursors and when they apply
in transportation conformity
determinations in PM
2.5
nonattainment
and maintenance areas.
Finally, on March 10, 2006, EPA
promulgated a final rule (71 FR 12468)
that establishes the criteria for
determining which transportation
projects must be analyzed for local
particle emissions impacts in PM
2.5
and
PM
10
nonattainment and maintenance
areas. If required, an analysis of local
particle emissions impacts is done as
part of a transportation project’s
conformity determination.
Transportation conformity for the
PM
2.5
standards began applying in PM
2.5
nonattainment areas on April 5, 2006,
one year after the effective date of EPA’s
PM
2.5
nonattainment designations (i.e.,
April 5, 2005). CAA section 176(c)(6)
and 40 CFR 93.102(d) provide a one-
year grace period before conformity
applies in areas newly designated
nonattainment for a new standard. PM
2.5
SIP submissions such as RFP and
attainment demonstrations would
identify motor vehicle emissions
budgets (‘‘budgets’’) for direct PM
2.5
or
PM
2.5
precursors, as described below.
These budgets would be used for
satisfying transportation conformity
requirements, once the budgets are
found adequate or the SIP containing
the budgets is approved by EPA. For
example, state and local agencies would
consider during the development of the
PM
2.5
SIP whether reductions of on-road
mobile source S0
2
emissions are a
significant contributor to an area’s PM
2.5
air quality problem, and if so, establish
a S0
2
motor vehicle emissions budget
for transportation conformity purposes.
The EPA has previously addressed its
intentions regarding when budgets must
be established in PM
2.5
SIPs for
transportation conformity purposes.
RFP plans, attainment demonstrations,
and maintenance plans must include a
budget for direct PM
2.5
emissions,
except for certain cases as described
below. All PM
2.5
SIP budgets would
include directly emitted PM
2.5
motor
vehicle emissions from tailpipe, brake
wear, and tire wear. States should also
consider whether re-entrained road dust
or highway and transit construction
dust are significant contributors and
should be included in the PM
2.5
budget.
For further information, see 40 CFR
93.102(b) and 93.122(f) of the
transportation conformity regulation, as
well as Sections VIII–X of the July 1,
2004 conformity rule preamble at 69 FR
40031–40036.
Under certain circumstances, directly
emitted PM
2.5
from on-road mobile
sources may be found an insignificant
contributor to the air quality problem
and NAAQS. Section 93.109(k) of the
conformity rule states that ‘‘[s]uch a
finding would be based on a number of
factors, including the percentage of
motor vehicle emissions in the context
of the total SIP inventory, the current
state of air quality as determined by
monitoring data for that NAAQS, the
absence of SIP motor vehicle control
measures, and historical trends and
future projections of the growth of
motor vehicle emissions.’’ The EPA
discussed its intentions for applying the
insignificance provision in the July 2004
final rule (69 FR 40061–40063).
In the May 6, 2005 final rule, EPA
provided details regarding when states
must establish SIP budgets for any PM
2.5
precursor (i.e., NO
X
, VOCs, S0
2
and
ammonia). If through the SIP process a
state concludes that on-road mobile
source emissions of one or more
precursors are significant (i.e. need to be
addressed in order to attain the PM
2.5
standards as expeditiously as
practicable), then EPA expects that the
state will include a budget in the SIP for
each of the relevant precursors. (70 FR
24287) The EPA also noted in the May
2005 conformity rule that, if inventory
and modeling analyses demonstrating
RFP, attainment or maintenance
indicate a level of emissions of a
precursor that must be maintained to
demonstrate compliance with the
applicable requirement, then that level
of emissions should be clearly identified
in the SIP as a budget for transportation
conformity purposes, even if the SIP
does not establish particular controls for
the given precursor. If the state fails to
identify such a level of emissions as a
budget, EPA will find the submitted SIP
budgets inadequate because the SIP fails
to clearly identify the motor vehicle
emissions budget as required by the
conformity rule (40 CFR
93.118(e)(4)(iii)). (70 FR 24287) In
determining whether the on-road mobile
source emissions of a PM
2.5
precursor
are significant, state and local agencies
would use the criteria for insignificance
findings provided in 40 CFR 93.109(k)
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of the transportation conformity
regulation. A further discussion of the
criteria to be considered in establishing
PM
2.5
precursor budgets is contained in
the May 2005 final transportation
conformity rule (70 FR 24282–24288). If
state and local agencies conclude that
on-road sources of a precursor are not a
significant contributor to the area’s
PM
2.5
air quality problem, as described
above, motor vehicle emissions budgets
would not be established even though
emissions may be addressed in the
area’s RFP plan, attainment
demonstration and/or maintenance
plan.
J. General Conformity
a. Background
The General Conformity regulations
promulgated in 1993 establish an
implementation process where Federal
agencies are responsible for making
their own determination of conformity
with State implementation plans (SIPs),
and EPA plays an advisory role.
Recognizing that it was impracticable to
evaluate all Federal actions for
conformity, EPA created a number of
exemptions in those regulations for
actions with insignificant or not
reasonably foreseeable emission
increases, including exemptions for
Federal actions with emissions below
specified
de minimis
levels. When a
Federal agency must demonstrate
conformity for an action, the regulations
provide several methods for making that
demonstration. With the designations of
PM
2.5
nonattainment areas on April 5,
2005, requirements for demonstrating
conformity become effective in those
areas on April 5, 2006.
On July 17, 2006 EPA issued a final
rule (71 FR 40420) to amend the General
Conformity Regulations to establish
de
minimis
levels for PM
2.5
for the General
Conformity program. The final rule
established 100 tons/year of direct PM
2.5
emissions and its precursors as the
de
minimis
level where the General
Conformity regulations would apply in
PM
2.5
nonattainment areas. In the
process of finalizing the
de minimis
level for PM
2.5
three comments were
received. One commenter was
concerned about emissions from
burning by Federal agencies. Another
commenter proposed that the
de
minimis
level for emissions of direct
PM
2.5
should be set significantly lower
than 100 tons—in the range of 25–50
tons per year (TPY) in areas that are
likely to attain the PM
2.5
national
ambient air quality standard within 5
years, and a level of 10–25 TPY in areas
that are likely to take more than 5 years
to achieve the national ambient air
quality standard. A third commenter
supported the proposed
de minimis
level.
The final rule revises the tables in
sub-paragraphs (b)(1) and (b)(2) of the
General Conformity Regulations by
adding a
de minimis
emission level for
PM
2.5
and its precursors. This action
maintained our past policy of
consistency between the conformity
de
minimis
emission levels and the size of
a major stationary source under the New
Source Review program (70 FR 65984).
These levels are also consistent with the
levels promulgated for Reasonably
Available Control Technology
applicability levels for volatile organic
compound and nitrogen oxide
emissions in subpart 1 areas under the
8-hour ozone implementation strategy
(68 FR 32843). Since EPA is not
finalizing any classifications for the
PM
2.5
nonattainment areas, we did not
establish differing PM
2.5
de minimis
emission levels for higher classified
nonattainment areas.
b. Comments and Responses
Comment:
One commenter requests
that EPA communicate to all Federal
agencies the value of the agencies
advising the States as soon as possible
of any planned future projects in
nonattainment areas that may be above
the General Conformity
de minimis
values or that will have to be evaluated
to show that they are below
de minimis
.
This is for projects that are very likely
to proceed. The aim is to consider these
future emissions in any growth
projections during SIP development
since such growth may not be
anticipated well by the available growth
model (E–GAS). States can
communicate with existing Federal
facilities now concerning this issue.
Response:
The EPA sees the value in
Federal agencies working with States to
anticipate growth in emissions and
include those anticipated emissions in
the applicable SIP. The EPA is in the
process of proposing regulatory
amendments to the General Conformity
regulations that provide a framework for
Federal facilities to work with States to
account for facility-wide emissions in
SIPs and to include Federal facility
emissions in future SIPs. The EPA
anticipates that these rule amendments
should be proposed before the end of
summer 2006.
Comment:
Some commenters stated
that the
de minimis
level for PM
2.5
for
conformity applicability should be less
than 100 tons per year. A level of 50
tons per year was suggested for direct
PM
2.5
emissions.
Response:
Similar comments were
received when the PM
2.5
de minimis
level was proposed on April 5, 2006.
The response to those comments can be
found in the preamble to the final rule
setting the
de minimis
level for PM
2.5
at
71 FR 40420.
Comment:
Are the precursors for
general conformity consistent with this
rulemaking or with the transportation
conformity rulemaking?
Response:
The precursors for general
conformity are generally consistent both
with this rule and the transportation
conformity rule. The only difference
between the transportation rule and this
rule is that SO
2
is not considered a
precursor for transportation conformity
determinations that occur prior to a
PM
2.5
SIP unless EPA or the State air
agency finds on-road mobile source
emissions significant. For more
information, see the May 6, 2005
transportation conformity rule on PM
2.5
precursors at 70 FR 24283. Since general
conformity includes analysis of
stationary sources the general
conformity rule requires SO
2
as a
precursor both before and after a PM
2.5
SIP is submitted.
Comment:
When will rulemaking
containing the
de minimis
levels for
PM
2.5
and for the precursors be issued?
There is some confusion, since the
proposed rule says that states should
assume 100 tpy for all PM
2.5
pollutants,
as this would make it consistent with
the levels for NO
X
and VOC for the
subpart 1 areas under 8-hour ozone.
However, since New Jersey’s
classification is moderate under the 8-
hour ozone standard and we are in an
Ozone Transport Region, the
de minimis
level for VOC is 50 tons per year.
Response:
On July 17, 2006 EPA
issued a final rule (71 FR 40420) to
amend the General Conformity
Regulations to establish
de minimis
levels for PM
2.5
for the General
Conformity program. The final rule
established 100 tons/year of direct PM
2.5
emissions and its precursors as the
de
minimis
level where the General
Conformity regulations would apply in
PM
2.5
nonattainment areas. Since EPA is
not finalizing any classifications for the
PM
2.5
nonattainment areas, we did not
establish differing PM
2.5
de minimis
emission levels for based on a
classification scheme.
Comment:
If a Statement of
Conformity has been issued on a project
and if the project has not been
completed to date, are they required to
address PM
2.5
prior to completion of the
project or will they be grandfathered in?
Response:
If a Federal action has
completed a conformity determination
and the action has started (regardless of
whether the project is complete or not)
then no new determination is needed. If
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the conformity determination was
completed, but the action did not start
in 5 years a new determination is
needed under the general conformity
rules.
Comment:
What guidance should
states use to establish budgets for large
facilities or military bases?
Response:
The EPA has not issued
any guidance for States and Federal
facilities to establish facility-wide
budgets in the applicable SIP. There is
nothing in the General Conformity
regulations preventing this approach
which would allow Federal actions that
do not increase total facility emissions
over the budget in the SIP from
determining the action conforms on the
basis of its compliance with the budget
limit. The EPA sees this practice as a
positive step to encourage States and
Federal agencies to work together to
account for emissions in a SIP so they
conform with the purposes and goals of
the SIP. The EPA intends to address the
approach and provide guidance in
planned revisions to the General
Conformity regulations which are
expected to be proposed in 2006.
K. Emission Inventory Requirements
a. Background
Emission inventories are critical for
the efforts of State, local, tribal and
federal agencies to attain and maintain
the NAAQS that EPA has established for
criteria pollutants including PM
2.5
.
Pursuant to its authority under section
110 of Title I of the CAA, EPA has long
required States to submit emission
inventories containing information
regarding the emissions of criteria
pollutants and their precursors. The
EPA codified these requirements in 40
CFR part 51, subpart Q in 1979 and
amended them in 1987.
The 1990 CAAA revised many of the
provisions of the CAA related to
attainment of the NAAQS and the
protection of visibility in mandatory
Class I Federal areas (certain national
parks and wilderness areas). These
revisions established new emission
inventory requirements applicable to
certain areas that were designated
nonattainment for certain pollutants. In
the case of particulate matter, the
emission inventory provisions are in the
general provisions under Section
172(c)(3).
In June 2002, EPA promulgated the
Consolidated Emissions Reporting Rule
(CERR) (67 FR 39602; June 10, 2002), 40
CFR part 51 subpart A. The CERR
consolidated the various emissions
reporting requirements that already
existed into one place in the CFR,
established new reporting requirements
for PM
2.5
and ammonia, and established
new requirements for the statewide
reporting of area source and mobile
source emissions.
The CERR established two types of
required emission inventories: annual
inventories, and 3-year cycle
inventories. The annual inventory
requirement is limited to reporting
statewide emissions data from the larger
point sources. For the 3-year cycle
inventory, States need to report data
from all of their point sources plus all
of the area and mobile sources on a
statewide basis. A special case existed
for the first 3-year cycle inventory for
the year 2002 which was due on June 1,
2004.
The EPA issued guidance suggesting
that 2002 be used as the Base Year for
8-hour ozone, PM
2.5
and regional haze
planning efforts (November 18, 2002
EPA memorandum ‘‘2002 Base Year
Emission Inventory SIP Planning: 8-hr
Ozone, PM
2.5
and Regional Haze
Programs’’
http://www.epa.gov/ttn/
chief/eidocs/2002
baseinven
_
102502new.pdf
).
States should estimate mobile source
emissions by using the latest emissions
models and planning assumptions
available at the time the SIP is
developed. Information and guidance on
the latest emissions models is available
at
http://www.epa.gov/otaq/
stateresources/transconf/
policy.htm#models
and at
http://
www.epa.gov/otaq/models.htm.
By merging the information on point
sources, area sources and mobile
sources into a comprehensive emission
inventory, State, local and tribal
agencies may do the following:
Set a baseline for SIP development.
Measure their progress in reducing
emissions.
Have a tool to support future
trading programs.
Answer the public’s request for
information.
The EPA uses the data submitted by
the States to develop the National
Emission Inventory (NEI). The NEI is
used by EPA to show national emission
trends, as modeling input for analysis of
potential regulations, and other
purposes.
Most importantly, States need these
inventories to help in the development
of control strategies and demonstrations
to attain the annual and 24-hour PM
2.5
NAAQS. In April 1999, EPA published
the ‘‘Emissions Inventory Guidance for
Implementation of Ozone and
Particulate Matter National Ambient Air
Quality Standards (NAAQS) and
Regional Haze Regulations,’’ EPA–454/
R–99–006. The EPA updated this
guidance in November 2005.
46
The
current version of this guidance is
available at:
http://www.epa.gov/ttn/
chief/eidocs/eiguid/index.html.
The
EPA developed this guidance document
to complement the CERR and to provide
specific guidance to State and local
agencies and Tribes on how to develop
emissions inventories for 8-hour ozone,
PM
2.5
, and regional haze SIPs. While the
CERR sets forth requirements for data
elements, EPA guidance complements
these requirements and indicates how
the data should be prepared for SIP
submissions.
The SIP inventory must be approved
by EPA as a SIP element and is subject
to public hearing requirements, whereas
the CERR is not. Because of the
regulatory significance of the SIP
inventory, EPA will need more
documentation on how the SIP
inventory was developed by the State as
opposed to the documentation required
for the CERR inventory. In addition, the
geographic area encompassed by some
aspects of the SIP submission inventory
will be different from the statewide area
covered by the CERR emissions
inventory. The CERR inventory was due
June 1, 2004, while the SIP inventory
due date is later. Because of this time
lapse, the State may choose to revise
some of the data from the CERR when
it prepares its SIP inventory to account
for improvements in emissions
estimates. If a State’s 2005 emission
inventory (or a later one) becomes
available in time to use for timely
development of a nonattainment area
SIP, then that inventory can be used. We
also encourage the cooperation of the
Tribes and the State and local agencies
in preparing their emissions inventories.
b. Final Rule
In the proposed rulemaking, in
§ 51.1008(a), to meet the emission
inventory requirements of section
172(c)(3), EPA proposed to require
submission of the CERR inventories as
well as ‘‘any additional emission
inventory information needed to
support an attainment demonstration
and RFP plan ensuring expeditious
attainment of the annual and 24-hour
PM
2.5
standards.’’ Section 51.1008(b) set
forth specifications for baseline
emissions inventories for attainment
demonstrations and RFP requirements.
Section 51.1008 of the final rule reflects
our proposed rule but is different from
the draft regulatory text. The proposal
did not specify a deadline for
46
Emissions Inventory Guidance for
Implementation of Ozone and Particulate Matter
National Ambient Air Quality Standards (NAAQS)
and Regional Haze Regulations,’’ (EPA–454/R–05–
001, November 2005.
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submission of the emission inventory.
To ensure clarity, the final rule contains
language addressing the deadline for
submission of emissions inventories for
nonattainment areas under section
172(c)(3) and section 172(b), and reflects
the statutory requirement of no later
than 3 years after designation of the
area. See § 51.1008(a). In addition,
§ 51.1008(a)(1) of the proposed rule has
been changed for purposes of
clarification. The proposal referred to
the requirement to submit statewide
emission inventories under the (CERR),
contained in 40 CFR part 51, subpart A.
The final regulatory text clarifies this to
refer to the requirements for data
elements under 40 CFR part 51, subpart
A. The EPA did not intend that the
emissions inventories developed under
the CERR, which are statewide, would
be appropriate for and satisfy all aspects
of SIP inventories developed for SIP
submissions. Section 51.1008(b) has a
minor change to clarify that this
subsection refers to the inventories
required for submission under
paragraph (a) of section 51.1008, and
also clarifies the reference to 40 CFR
Part 51 subpart A, which currently
contains the CERR. In addition, section
51.1008(b) as finalized provides that
‘‘The baseline emission inventory for
calendar year 2002 or other suitable year
shall be used for attainment planning
and RFP plans for areas initially
designated nonattainment for the PM
2.5
NAAQS in 2004.’’ The EPA added this
flexibility to be consistent with EPA’s
ozone implementation rule, and to
enable a State to use a more recent and
improved base year inventory if it is
completed in time to allow for timely
development of the attainment plan. As
noted above, we expect that States will
consult the guidance document titled
Emission Inventory Guidance for
Implementation of Ozone and
Particulate Matter National Ambient Air
Quality Standards (‘‘NAAQS’’) and
Regional Haze Regulations,
November
2005,and submit inventories that are
appropriate for the geographic area at
issue and consistent with regulations
and this guidance. We expect the States
to include in their SIP submission
documentation explaining how the
emissions data were calculated.
In the proposed rulemaking, EPA
asked ‘‘What emission inventory
requirements should apply under the
PM
2.5
NAAQS.’’ Several specific
questions followed this general question
to assess whether or not additional
emission inventory requirements or
guidance are needed to implement the
proposed standard. It was noted in the
proposal that the basis for EPA’s
emission inventory program is specified
in the Consolidated Emissions
Reporting Rule (CERR) and the related
guidance document titled
Emissions
Inventory Guidance for Implementation
of Ozone and Particulate Matter
National Ambient Air Quality
Standards (NAAQS) and Regional Haze
Regulations.
Subsequent to the proposed
rulemaking, EPA proposed the Air
Emissions Reporting Rule (AERR) at 71
FR 69 (Jan. 3, 2006). The AERR would
update CERR reporting requirements by
consolidating and harmonizing new
emissions reporting requirements with
pre-existing sets of reporting
requirements under the Clean Air
Interstate Rule (CAIR) and the NO
X
SIP
Call. At this time, EPA is reviewing
comments submitted on the AERR
proposal and expects to finalize this
rulemaking during calendar year 2007.
The AERR is expected to be a means by
which the Agency will implement
additional data reporting requirements
for PM
2.5
SIP emission inventories.
Since the AERR rulemaking is in
progress, EPA believes it is appropriate
to defer responding to certain comments
on the proposed PM
2.5
Implementation
Rule related to data reporting and
emission inventory requirements that
were discussed in the AERR proposal.
Those comments will be addressed in
the final AERR rulemaking. Significant
comments that are separable from the
AERR rulemaking and relate to data
reporting and emission inventory
requirements for the PM
2.5
NAAQS are
addressed below and in EPA’s
Responses to Comments document.
With respect to SIP emission
inventory requirements under this
rulemaking, EPA recognizes NO
X
, SO
2
,
VOCs, and ammonia as potential
precursors of PM
2.5
because these
pollutants can contribute to the
formation of PM
2.5
in the ambient air. To
provide a technical foundation for
understanding contributions to PM
2.5
nonattainment problems and for
identifying potential future measures to
reduce PM
2.5
concentrations, EPA is
requiring under 40 CFR part 51 subpart
A and 40 CFR 51.1008 of this rule that
States develop and submit inventories
for direct PM
2.5
and all precursors of
PM
2.5
. This requirement stands apart
from the policies in this rule regarding
the required treatment of various
precursor emissions in the development
of control strategies for attaining the
PM
2.5
standards. With respect to the
latter requirements, EPA has not made
a finding that all precursors should be
evaluated for potential control measures
in each specific nonattainment area. The
policy approach in the rule instead
requires evaluation of control measures
for direct PM
2.5
and sulfur dioxide in all
areas, and describes general
presumptive policies that NO
X
sources
need to be evaluated for control
measures in all areas unless findings of
insignificance are made, but that control
measure evaluations are not required for
sources of ammonia and VOC unless
findings of significance are made. The
rule also provides a mechanism by
which the State and/or EPA can make
an area-specific demonstration to
reverse the general presumption for
these three precursors. (See section
II.A.8 for additional discussion on these
issues.)
c. Comments and Responses
1. Should EPA Specify an Inventory
Approval Process?
Comment:
Several commenters
indicated that the current process of
approving SIP inventories by EPA
regional offices is appropriate and did
not believe that additional approval
requirements were necessary. Some
commenters noted that flexibility is
needed to address regional concerns.
Several commenters noted that SIP
emission inventories may include
requirements or information in addition
to data required by the Consolidated
Emissions Reporting Rule (CERR). One
commenter observed that States
routinely develop information outside
the CERR for purposes of their SIP
development and that additional
requirements should not be defined by
EPA. Another commenter recommended
that requirements for nonattainment
area emission inventories be
incorporated in the CERR or AERR. A
few commenters felt that additional
guidance was needed on the SIP
emission inventory approval process.
Response:
The SIP emissions
inventory is a plan provision that must
be approved by EPA under section
110(k) of the CAA and is subject to
public hearing requirements pursuant to
section 110(a)(2). The EPA believes that
it need not further specify a SIP
approval process for emissions
inventories beyond that set forth in the
statute, regulation (51.1008), other
related sections of this rulemaking and
EPA’s current guidance. The EPA agrees
with many of the commenters that the
approval process for SIP emission
inventories need not be further defined
and that approval should be conducted
at the regional level to provide
flexibility to address regional concerns.
The EPA also agrees that use of Quality
Assurance Project Plans developed for
each state will be helpful in establishing
the proper approval process. The EPA
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addresses the issue of what data
elements are needed for SIP approval in
the responses to comments below,
including the responses to comments
under Issue 2, below.
As noted by two commenters EPA
describes procedures for approval of SIP
inventories in a document titled
Emissions Inventory Guidance for
Implementation of Ozone and
Particulate Matter National Ambient Air
Quality Standards (NAAQS) and
Regional Haze Regulations,
November
2005. Section 2.5, Inventory Approval,
references a memorandum titled
Public
Hearing Requirements for 1990 Base-
Year Emissions Inventories for Ozone
and CO Nonattainment Areas,
September 29, 1992.
The EPA intends to
use the procedures discussed in the
guidance and memorandum to the
extent that they are applicable to
approval of PM
2.5
emission inventories
submitted as part of the SIP. 40 CFR
51.1008 sets forth the requirements for
emissions inventories under section
172(c)(3), which will be reviewed in the
context of the SIP approval process. See
also 40 CFR 51.1007 and 51.1009
regarding attainment demonstrations
and RFP plans. Thus, EPA believes that
its existing SIP approval process is
adequately described in statute,
regulation and guidance, and that it
provides flexibility to deal with issues
that arise in individual nonattainment
areas.
2. Are the Data Elements Specified
Within the CERR Sufficient To Develop
Adequate SIPs? For Example, in the
Determination of RACT, Should More
Information on Existing Control Devices
Be Required?
Comment:
Several commenters
recommended that any additional
reporting requirements should be
addressed through the CERR/AERR and
associated guidance and that no
additional reporting requirements
should be specified in the Rule. Another
commenter stated that more detail
concerning control equipment would be
helpful but was concerned about the
additional burden on industry
compared to the benefit to State and
local agencies, and suggested that this
would be further addressed in the
context of comments on the AERR. One
commenter believed that the reporting
requirements within the CERR are
sufficient to develop a PM
2.5
SIP for
most areas but noted that nonattainment
areas may require additional inventory
information which will need evaluation
on a case-by-case basis. The commenter
further stated that any additional
inventory requirements should be
identified during the SIP development
process, in cooperation with the EPA
regional office, and should not be part
of this rule.
Response:
In section 40 CFR
51.1008(a)(1) of the final rule, EPA
incorporates the requirements for data
elements required under 40 CFR part 51,
subpart A, which contains the CERR, for
inventories submitted under this
section. The EPA notes, however, that
the issue of whether to require
additional reporting requirements
beyond those required in the CERR is
currently being addressed in the Air
Emissions Reporting Rule (AERR) 71 FR
69 (January 3, 2006). At this time EPA
believes that the requirements for data
elements under the CERR, in
conjunction with the other provisions of
40 CFR 51.1008, as well as 40 CFR
51.1007 and 51.1009, are generally
adequate to meet the needs for PM
2.5
nonattainment emission inventory SIP
development. The AERR as proposed
includes additional provisions which
may be helpful for PM
2.5
SIP emission
inventory development. The EPA will
address this aspect of the AERR,
including comments received in this
rulemaking on the issues raised and the
additional elements proposed in the
AERR, in the final AERR rulemaking.
This final rule indicates that States shall
include data elements for PM
2.5
inventories as required under 40 CFR
part 51, subpart A. In addition, 40 CFR
51.1008(a)(2) requires that States submit
‘‘any additional emission inventory
information needed to support an
attainment demonstration and RFP plan
ensuring expeditious attainment of the
annual and 24-hour PM
2.5
standards.’’
See also 40 CFR 51.1007 and 51.1009.
Thus States should be aware that data
elements in addition to those required
under the CERR may be needed to
support attainment demonstrations and
RFP inventories. Additional data
elements needed for other SIP emission
inventory purposes should be handled
on a case-by-case basis. Because of the
nature of SIP development, which varies
depending on the nature and needs of
individual areas, it may not be possible
to require a level of detail in regulations
that will enable a ‘‘one-stop-shop’’
information request as suggested by one
of the commenters.
As recommended by one commenter,
guidance on reporting requirements is
contained in
Emissions Inventory
Guidance for Implementation of Ozone
and Particulate Matter National
Ambient Air Quality Standards
(NAAQS) and Regional Haze
Regulations
(EPA–454/R–05–001,
November 2005). For example, Section
3.2.1 for Pollutant and Pollutant
Precursors to be Inventoried presents
guidance to states on PM
2.5
pollutants
and their components that should be
reported for PM
2.5
SIP development. See
also section 5, Emission Inventory
Development, and other related sections
of the guidance.
With respect to the comment on
additional detail on control
requirements, see also EPA’s Response
to Comment Document.
3. Is the Current Approach for Reporting
Specific Pollutants Sufficient, or Should
EPA Require More Specific Emission
Component Reporting Such as Groups
of Compounds or Reporting of
Elemental Carbon and Organic Carbon?
Comment:
Currently the CERR
requires the reporting of SO
2
, VOC,
NO
X
, CO, Pb, PM
10
, PM
2.5
, and NH
3
.
VOC and PM are speciated by the
emissions processing models based on
speciation profiles for specific source
categories. Most commenters supported
retaining the existing reporting
requirements under the CERR. Others
encouraged expansion of the
requirements to include reporting of
specific organic compounds and organic
fractions although some thought this
should be a requirement while others
thought it should be optional. One
commenter thought that EPA should
work with industry trade groups to
develop and improve the speciation
profiles of the most important source
categories rather than asking the state
and local agencies to characterize VOC
and PM species. Several commenters
thought that EPA should encourage the
reporting of PM components (filterable,
condensable and total) for development
of control strategies and attainment
demonstrations. Another commenter
noted that including condensable
emissions raises ‘‘uncertainty’’ issues
and urged EPA to devote resources to
developing better test methods. One
commenter believed that in addition to
reporting PM
2.5
and its components,
states should report all precursors to
PM
2.5
(SO
2
, NO
X
, ammonia and VOC).
Response:
The EPA agrees with the
commenters who argued that the need
for additional speciation should be
determined based on specific SIP needs.
40 CFR part 51, subpart A which
contains the CERR, does not require
reporting of specific compounds or
compound groups nor does it require
reporting of organic and elemental
carbon fractions. As discussed in the
response to comment above, EPA
believes that the requirements for data
elements contained in 40 CFR part 51
subpart A, in conjunction with the
provisions of 40 CFR 51.1008, are
generally adequate to meet the needs for
PM
2.5
nonattainment emissions
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inventory SIP development. Section
51.1008(a)(1) applies the data element
requirements contained in 40 CFR part
51 subpart A. Section 51.1008(a)(2)
requires States to submit ‘‘any
additional emission inventory
information needed to support an
attainment demonstration and RFP plan
ensuring expeditious attainment of the
annual and 24-hour PM
2.5
standards.’’
Thus data elements in addition to those
required under the CERR may be needed
to support attainment demonstrations
and RFP inventories under 40 CFR
51.1008(a)(2). Additional data elements
needed for other SIP emission inventory
purposes should be handled on a case-
by-case basis. Where States need to
develop speciated emissions for PM
2.5
SIP emission inventories, EPA provides
guidance in the document titled
Emissions Inventory Guidance for
Implementation of Ozone and
Particulate Matter National Ambient Air
Quality Standards (NAAQS) and
Regional Haze Ozone Regulations,
November 2005. Section 3.2.1,
Pollutants and Pollutant Precursors to
be Inventoried identifies pollutants and
their components to be reported for
PM
2.5
SIPs. Section 3.3.5, Speciation
Procedures, discusses the preferred
approach for speciating PM
2.5
emission
inventories for use in ambient air
quality simulations. The approach
discussed in the guidance is application
of emission models which use
speciation profiles to estimate the mass
of specific compounds and compound
groups for VOC and elemental and
organic carbon fractions for PM. The
EPA encourages further research and
development of technical tools to better
characterize emissions inventories for
specific VOC compounds and to
determine the extent of specific VOC
compounds and organic PM mass. The
EPA also encourages States to continue
efforts to refine their ammonia
inventories. See sections II.A.3 and
II.A.4 of the Preamble.
As discussed in the guidance
document, EPA encourages reporting of
organic and elemental fractions of PM
2.5
by state agencies (see Section 3.2.1,
Pollutants and Pollutant Precursors to
be Inventoried). While elemental or
black carbon (EC/BC) and organic
carbon (OC) will be identified in default
speciation profiles, more locally-specific
data should be collected where available
as an input to model preprocessing.
Where such data are available, they
should be provided to EPA to help in
improving EPA’s speciation profiles.
Certain organic gases have been
identified as precursors to secondary
organic aerosols (SOA). Toluene, xylene
and ethyl benzene are known to be
important SOA precursors. Additional
organic gases may be identified by
ongoing research. While these gases will
be identified in default speciation
profiles, more locally-specific data
should be collected, where available, as
an input to model preprocessing. State,
local and Tribal agencies can contact
EPA’s EIAG for more information.
EPA agrees with the comment that it
should take the lead in updating VOC
and PM profiles for most important
source categories. The Agency is close
to completing a multi-year effort to
update the SPECIATE database.
SPECIATE is EPA’s repository of Total
Organic Compound (TOC) and PM
speciated profiles for a wide variety of
sources. The profiles in this system are
provided for air quality dispersion
modeling and as a library for source-
receptor and source apportionment type
models. This recent initiative to update
SPECIATE was needed because
speciated emissions profiles continue to
be developed and the data in the
existing EPA database (SPECIATE 3.2)
was becoming outdated.
This work was coordinated with
interested parties including industry
through an Agency sponsored
workgroup. It has depended largely on
the collection and review of existing
profile data to accomplish, as the
commenter suggests, delivering the best
results for the least amount of resources
spent. Previously, these data were not
widely available to emission inventory
developers and lacked the quality
assurance review and evaluation needed
to develop profiles used by emissions
models to generate speciated emissions.
As suggested by the commenter, the
workgroup was used to help prioritize
source categories for investigation to
ensure that updates to existing profiles
and development of new profiles
focused on areas of greatest need.
SPECIATE v4.0 contains more than
2500 source profiles and is currently
undergoing peer review. The EPA
expects the final work product to be
available for use by emission inventory
preparers during early calendar year
2007 and it will be distributed through
EPA’s CHIEF Web site.
The EPA agrees with a commenter
who noted that in order to meet the
requirements under section 172(c) of the
CAA for ‘‘a comprehensive, accurate,
current inventory * * *,’’ condensable
emissions of PM
2.5
and PM
2.5
precursors
are important to support development of
local control strategies and attainment
demonstrations. The EPA believes that
the final rule provides for the
submission of PM
2.5
nonattainment area
inventories meeting the requirements of
section 172(c)(3).
Section 51.1008(a)(1) requires that
States submit emission inventories for
PM
2.5
that satisfy the data elements
reporting requirements under 40 CFR
part 51 subpart A, which contains the
CERR. The CERR requires reporting of
‘‘Primary PM
2.5
’’ which is defined as the
sum of the filterable and condensable
portions of PM
2.5
. Therefore, SIP base
year inventories will include the
condensable fraction of PM which was
of concern to several commenters. The
CERR also requires reporting of SOx,
NO
X
, ammonia and VOC which are
potential precursors to PM
2.5
. EPA notes
that the AERR as proposed would
require reporting of the same precursors
and would also require reporting of
Primary PM
2.5
. However, the proposed
AERR requires the reporting of the
filterable and condensable fractions of
PM
2.5
(optional under the CERR) in
addition to the primary PM
2.5
total mass.
The EPA will address this requirement
in its final rulemaking on the AERR.
As noted above, in addition to the
data element requirements under
section 51.1008(a)(1), under section
51.1008(a)(2) States must submit ‘‘any
additional emission inventory
information needed to support’’ an
attainment demonstration and RFP plan.
Thus States should be aware that data
elements in addition to those required
under the CERR may be needed to
support attainment demonstrations and
RFP inventories under 40 CFR Part
51.1008(a)(2). Additional data elements
needed for other SIP emission inventory
purposes should be handled on a case-
by-case basis.
The EPA is aware of the issues raised
by one commenter regarding
measurement uncertainty for
condensable PM. This issue is
addressed in detail under Section II.L of
the preamble (‘‘Condensable particulate
matter test methods and related data
issues,’’). We believe that for purposes
of emissions inventories and attainment
demonstrations, States should continue
to describe the impacts of baseline
emissions and develop future air quality
strategies using information available on
primary PM
2.5
emissions, including
condensable PM
2.5
. However, with
respect to developing enforceable
emissions limits for condensable PM
2.5
emissions, the final rule reflects EPA’s
adoption of a transition period during
which we will allow time for
development of emissions limits for
condensable PM
2.5
. See 40 CFR
51.1002(c).
For additional comments and
responses related to speciation issues,
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see the Response to Comments
Document.
4. Should EPA Require That States
Develop Their Own Estimates for Area
and Mobile Source Emissions?
Comment:
The CERR allows states to
adopt EPA developed emission
estimates from area and mobile sources
in lieu of making those estimates
themselves if they accept these
estimates for their emission inventory.
One commenter thought that EPA
should require States to develop their
own estimates for area and mobile
sources based on the specified 2002
base year. Three commenters thought
that the existing process (under the
CERR) was adequate. One of the
commenters expressed concerns about
the reporting burden for States if they
were required to compile their own
mobile and area source inventories.
Another commenter did not believe that
States should be required to submit data
on area and mobile sources but noted
that many States would continue to run
the MOBILE model for onroad mobile
sources and calculate area source data
for SIP emission inventories. Two of the
commenters thought that the existing
process provided flexibility needed by
States to focus on source categories of
most concern and address problematic
areas with special inventory needs. One
commenter recommended that EPA
continue developing models for area
and mobile sources.
Response:
The EPA strongly
encourages states to submit their own
estimates for area (nonpoint) and mobile
sources unless they can establish that it
is impracticable to do so, given time and
resources. We will continue, in
appropriate circumstances, to allow a
State to use EPA-developed emission
estimates for mobile and nonpoint
sources in lieu of making those
estimates itself if the State accepts the
estimates for its emission inventory.
While this has been the case with
respect to reporting under the CERR for
the 3-year cycle inventories, for
development of emission inventories to
support PM
2.5
SIPs, the ability to rely on
EPA-developed emission estimates for
development of emission inventories to
support PM
2.5
SIPS is more complex and
problematic. For mobile sources, the
practical use of these EPA-developed
mobile source inventories in a SIP may
be very limited. While EPA has
developed inventories for 2002, states
will still have to develop attainment
year inventories, including projections
of future activity and the effects of
control measures. For mobile sources,
future year inventories are not
developed by simply growing a base
year inventory, but instead are
developed by running an emissions
model with appropriate inputs for the
future year. In order to develop an
attainment demonstration that
accurately accounts for the change in
emissions from the base year to the
attainment year, inventories for both of
those years will need to be developed
using consistent methods and modeling
assumptions. For mobile sources
especially, it may be very difficult for
states to replicate the methods used by
EPA for the base year when creating the
attainment year inventory.
In addition, states cannot use the EPA
developed inventories for the base year
if newer models or planning
assumptions are available at the time
they begin working on the SIP. For
example, if new or better information
about the composition of the local fleet
of highway vehicles in the base year
becomes available to the state after the
EPA developed inventories were
created, that information should be used
by the state to create a new base year
inventory.
Given the need for emissions
modeling for mobile sources in the
projection year, the need for consistency
in tools and methods between the base
year and attainment year, and the need
to use latest available models and
planning assumptions, EPA believes
that most if not all states will choose to
develop their own base year inventories
for mobile sources.
With respect to nonpoint (area) source
emissions, States must make every
effort, consistent with available timing
and resources to ensure that their area
source emission inventories are as
accurate as possible. While EPA
prepares a national area source emission
inventory that covers all counties, it is
designed for national analyses. EPA
does not have access to the more
detailed information available to States
that is used to develop an area source
inventory. Therefore, states should
develop as much of their area source
inventory as possible using local and
State information, and in particular
should develop the inventory for the
most significant area source categories
which are critical to ensuring overall
accuracy. Where time and resources
preclude a State from developing the
estimates for less-critical area source
categories, the State may rely on EPA-
developed area source emissions
information for those categories.
The EPA points out that although
guidance has recommended that 2002
be used as the base year for emissions
inventories for states initially
designated nonattainment in 2004–5,
states remain free to use an alternate
base year, as appropriate. Section
51.1008(b) provides in relevant part that
‘‘The baseline emission inventory for
calendar year 2002 or other suitable year
shall be used for attainment planning
and RFP plans for areas initially
designated nonattainment for the PM
2.5
NAAQS in 2004.’’
EPA agrees with the comment that it
should continue to develop models and
other emission estimation tools. As an
example, EPA’s Office of Transportation
and Air Quality (OTAQ) is developing
a modeling system termed the Motor
Vehicle Emission Simulator (MOVES).
This new system will estimate
emissions for on-road and nonroad
sources, cover a broad range of
pollutants, and allow multiple scale
analysis, from fine-scale analysis to
national inventory estimation. When
fully implemented MOVES will serve as
the replacement for MOBILE6.2 and
NONROAD. In addition, as the NEI is
reengineered, OAQPS will examine the
need for updating emissions estimation
guidance materials and developing tools
which will assist State agencies in
estimating emissions from area source
categories. See also EPA’s ‘‘Emissions
Inventory Guidance for Implementation
of Ozone and Particulate Matter
National Ambient Air Quality Standards
(NAAQS) and Regional Haze
Regulations,’’ November 2005.
5. Other Inventory Issues
The EPA’s responses to additional
comments concerning emission
inventory issues can be found in EPA’s
Response to Comments Document.
L. Condensable Particulate Matter Test
Methods and Related Data Issues
a. Background
As noted in the preamble to the
November 1, 2005 proposed rule,
certain commercial or industrial
activities involving high temperature
processes (fuel combustion, metal
processing, cooking operations, etc.)
emit gaseous pollutants into the ambient
air which rapidly condense into particle
form. The constituents of these
condensed particles include, but are not
limited to, organic material, sulfuric
acid, and metals. Because condensable
emissions exist almost entirely in the
2.5 micrometer range and smaller, these
emissions are inherently more
significant for PM
2.5
than for prior
particulate matter standards addressing
larger particles. Therefore, we believe
that it is important that the air quality
management of particulate matter
promote a comprehensive approach to
condensable particulate matter.
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We proposed to require a
comprehensive inclusion of
condensable PM for all aspects of SIP
development for PM
2.5
. Under the
proposal, EPA would require
condensable PM to be considered in the
emissions inventories and analyses used
in attainment demonstrations. Also
under the proposal, any stationary
source emissions limits developed to
implement RACT or RACM would
reflect control and measurement of
condensable PM.
We received numerous comments on
whether these requirements were
unreasonable in light of the current state
of knowledge of and uncertainties
around the measurement of direct PM
2.5
.
Most commenters supported the overall
view that condensable PM should be
addressed in order to provide a
complete air quality management
program for PM
2.5
. On the other hand,
many commenters raised concerns
about the availability and
implementation of test methods and
related issues about the uncertainties in
existing data for condensable PM
2.5
. As
a result of the concerns, these
commenters believed EPA would be
premature in requiring a comprehensive
evaluation of condensable PM
2.5
,
especially as it related to developing
any new emissions limits for stationary
sources. In recognition of these
concerns, the final rule reflects EPA’s
adoption of a transition period during
which we will assess possible revisions
to available test methods and we will
allow time for States to update
emissions inventories as needed to
address direct PM
2.5
emissions. In this
section of the preamble, we outline the
elements of the final rule addressing
inventories reflecting control of direct
PM
2.5
. We also discuss the specific
comments raised regarding methods for
measuring direct PM
2.5
, both filterable
and condensable PM, in implementing
the rule. The particular comment areas
include defining test methods,
quantifying direct PM
2.5
for inventories,
and a transition period for developing
effective regulations. Below are also our
responses to those comments.
b. Final Rule
For the final rule, EPA addresses two
broad issues related to inclusion of
condensable PM. The first issue is
whether emissions inventories and
attainment demonstrations should
include the condensable portion of
direct PM
2.5
emissions. The second
issue is whether direct PM
2.5
emissions
limitations established by States for
purposes of RACT and RACM must
include limits on condensable PM
emissions or limits on total direct PM
2.5
that includes the condensable PM
fraction.
For purposes of developing emissions
inventories and attainment
demonstrations, the final rule reflects a
requirement to account for significant
contributors of direct PM
2.5
emissions,
both filterable and condensable PM
2.5
.
We recognize that some States have
established inventories consistent with
requirements of the consolidated
emissions reporting rule (CERR) to
report direct PM
2.5
emissions, including
condensable PM, in each inventory
revision. While uncertainties remain
with significant issues to address related
to our current knowledge base on
condensable PM emissions, we believe
that for purposes of emissions
inventories and attainment
demonstrations, States should continue
to describe the impacts of baseline
emissions develop future air quality
strategies using information available on
direct PM
2.5
emissions including
condensable PM.
With respect to developing
enforceable emissions limits for
condensable PM emissions, we note that
some States have established emissions
limits or otherwise require PM
emissions testing that includes
measurement of condensable PM. We
recognize that in some States there
remain questions about the viability of
available test methods, the availability
of representative direct PM
2.5
emissions
data, the uncertainty of the methods
used to establish inventories, and the
short time frame within which States
must develop SIPs. In response we have
decided to provide a transition period
for developing emissions limits and
regulations for condensable PM
2.5
.
During this transition period, we will
provide technical support to States as
requested in establishing effective PM
2.5
emissions limits and corresponding
emissions testing requirements.
As described further below, we will
devote resources early during this
transition period to assessing and
improving the available test methods for
condensable PM. During this transition
period, we will also solicit the
involvement of stakeholders with an
interest in conducting emissions testing
to collect updated direct PM
2.5
emissions data. The purpose of these
stakeholder projects will be to collect
new direct filterable and condensable
PM emissions data using methodologies
that provide data more representative of
source direct PM
2.5
emissions. The EPA,
States, and others will use these data to
improve emissions factors and to help
define or revise source emissions limits
in permits and State implementation
plans.
The time required for our
stakeholders and EPA to complete the
test method assessment will limit the
degree to which State and local agencies
can address effectively the necessary
direct PM
2.5
regulations in inventories
and in the 2008 SIP submittals. In
recognition of this, we will not require
that the emissions limits included in the
2008 submittals account for the
condensable fraction of direct PM
2.5
or
to establish limits for total direct PM
2.5
,
including condensable PM.
We will expect States to continue
developing more complete inventories
with regard to direct PM
2.5
emissions,
particularly for condensable PM, during
this transition period. We expect no
such allowance period for method
assessment or data collection to be
necessary for implementing regulations
addressing precursor PM
2.5
emissions.
The period of transition for
establishing emissions limits for
condensable direct PM
2.5
will end
January 1, 2011. We expect States to
address the control of direct PM
2.5
emissions, including condensable PM,
with any new actions taken after
January 1, 2011. For example, States
must address condensable PM
emissions in any direct PM
2.5
emissions
limits resulting from midcourse reviews.
Additionally, EPA expects that any
direct PM
2.5
regulations or limits
developed under any new NAAQS for
particulate matter would also address
condensable PM emissions.
Notwithstanding the issues and
uncertainties related to condensable
PM, EPA encourages States to identify
measures for reducing condensable PM
emissions, particularly where those
emissions are deemed significant
contributors to the control strategy
needed for expeditious attainment. We
wish to clarify that in order to take
credit in the SIP for reduction of any
such condensable PM emissions, there
must be enforceable limitations that
ensure that reduction in condensable
PM emissions. These enforceable limits
could take the form of a limitation on
the condensable PM emissions or total
direct PM
2.5
emissions (or a
commitment to develop such limitations
after the end of the transition period
described above). Alternatively, these
enforceable limitations could provide
for enforceable conditions that ensure
that the effect on condensable PM
emissions is assured (for example,
enforceable limitations on operating
temperature, or limits on FGD scrubber
operations which have the effect of
reducing condensable PM emissions).
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c. Comments and Responses
We received many comments on
quantification of direct PM
2.5
emissions
particularly about the need to conduct
further validations for the available test
methods, the availability of direct
filterable or condensable PM
2.5
data or
lack thereof for representative baselines,
and the procedures for applying
baseline data for developing effective
regulations.
1. Method 202
Comment:
A majority of commenters
characterized the performance of
Method 202 as lacking in reliability.
Some commenters characterized the
formation of artifacts in Method 202 as
significant and the primary reason for
their recommendation to defer the
inclusion of condensable particulate
matter in the baseline assessments and
regulatory development for the initial
SIPs. The commenters stated that the
principal artifact formed when using
Method 202 was the result of SO
2
dissolving in the impinger water and
converting to sulfuric acid.
Response:
We agree that SO
2
in
particular, and perhaps other gaseous
compounds, can react with the
collecting liquids used in the method to
form materials (artifacts) that would not
otherwise be solid or liquid or would
not condense upon exiting the stack. We
believe that when Method 202 is
applied appropriately (i.e., with the N
2
purge as prescribed), the SO
2
artifact
formation is reduced by as much as or
more than 90 percent; however, we
agree that further verification and
refinement would be appropriate to
verify the potential for artifact
formation.
In response, we are undertaking
laboratory studies in collaboration with
several stakeholders to characterize the
artifact formation and other
uncertainties associated with
conducting Method 202, and to identify
procedures to be used in applying
methods to minimize uncertainties. We
are involving stakeholders representing
industry and State and local agencies in
the project design and results review.
Stakeholders who have expressed
interest in participating in these studies
include the Electric Power Research
Institute, companies associated with the
National Environmental Development
Association’s Clean Air Project (NEDA/
CAP), the Portland Cement Association,
the Lime Manufacturing Association,
the American Foundry Association, the
National Aluminum Association, and
several governmental organizations
represented by National Association of
Clean Air Agencies. Other parties may
participate in the study as well.
By the end of 2007, we intend to have
conducted a comprehensive laboratory
study that examines the relationship
between several critical condensable PM
sampling and analysis parameters (e.g.,
SO
2
concentration, moisture
concentration, sample duration, and
water acidity) and the artifact formation
associated with the measurements. One
intended result of the project will be
identifying possible modifications to
Method 202 to minimize and quantify
the uncertainties. We will publish the
results of the laboratory study along
with an assessment of other input and
data from stakeholders on the EPA
website and, to the extent possible, in a
widely circulated peer review journal.
Also, to the extent necessary, we intend
to propose revisions to the method to
incorporate improvements and to clarify
application.
2. Conditional Test Methods 039
and 040
Comment:
Several commenters cited
as a deficiency that neither conditional
test method 040 (CTM–040) for
measuring filterable PM
2.5
nor the
dilution sampling method (CTM–039)
has been thoroughly validated through
EPA Method 301. There were also
comments that neither of the CTMs was
published in the
Federal Register
.
Response:
We agree with the
comments that neither method has been
subjected to adequate public notice and
comment rulemaking. Taking that step
will facilitate application of the
appropriate methods for implementing
the SIPs. On the other hand, there are
a number of levels of validation already
achieved for one or more of these
methods that will determine what, if
any, additional validation work will be
necessary. For example, while we could
seek resources to evaluate dilution
sampling technology, including CTM–
039, and to request public involvement
in the project planning, conduct, and
review with the possibility of a
Federal
Register
proposal, our preference would
be to incorporate by reference an
approved voluntary consensus test
method (e.g., ASTM standard).
We believe that a dilution sampling
method for measuring direct PM
2.5
eliminates essentially all artifact
formation and provides the most
accurate emissions quantification. To
the extent that we need to and can
secure resources and stakeholder
interest, we plan to perform additional
validation testing of CTM–039 or other
dilution sampling technologies to
characterize the precision of this
approach. In conjunction with our
validation efforts, we intend to continue
participation in the ASTM D22
committee to develop and publish a
dilution sampling method and
encourage other volunteers on that
committee to approve the consensus
based dilution sampling method. We
believe that this work is nearly
complete. As outlined above, we are
already undertaking laboratory studies
to assess the method and to identify
possible modifications to reduce
formation of these artifacts. Preliminary
laboratory evaluations conducted by
EPA and by Environment Canada
47
indicate that additional artifact
reductions of 60 to 90 percent may be
achieved with other minor
modifications to Method 202. These
preliminary findings indicate that
Method 202 is essentially a viable
method that these proposed laboratory
studies will serve to enhance. Within 18
months we intend to propose, if
necessary, modifications to Method 202
or similar methodologies suitable for
measuring condensable PM
2.5
.
As for CTM–040, we believe that
further validation of this method is
unwarranted since the technology and
procedures are based upon the same as
evaluated for promulgated Method
201A. Method 201A has undergone
public review and comment (55 FR
14246, April 17, 1990). Also, as noted
earlier, we have already begun
laboratory and data evaluation work the
possible result of which would be a
revised Method 202 to be proposed in
the
Federal Register
to include
improvements indicated by the
evaluation. At that same time, we may
propose CTM–040 to be used in
combination with Method 202 for
measuring direct PM
2.5
with additional
guidance on appropriate approaches to
testing for direct PM
2.5
emissions from
various types of control measures (e.g.,
electrostatic precipitator and flue gas
desulphurization combinations).
3. Role of Condensable PM Emissions in
Defining RACT
Comment:
Commenters indicated that
States must reassess and revise
emissions limits if the States adopt
methods for measuring direct PM
2.5
including condensable PM where not
required previously. Commenters noted
that most existing PM emissions limits
are not reflective of data collected with
47
‘‘Optimized Method 202 Sampling Train to
Minimize the Biases Associated with Method 202
Measurement of Condensable Particulate Matter
Emissions,’’ John Richards, Tom Holder, and David
Goshaw, Air Control Techniques, P.C.; Air & Waste
Management Association, Hazardous Waste
Combustion Specialty Conference AWM, November
2–3, 2005, St. Louis, MO.
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methods that measure condensable or
filterable PM
2.5
and, therefore, not
enforceable using a new or different test
method.
Response:
We agree that coordinating
the test method with the pollutant
defined by the emissions limit is critical
to an effective regulation. In the case of
direct PM
2.5
regulations, the methods for
measuring filterable and condensable
PM provide data that are significantly
different than do methods often used in
implementing many current regulations
(i.e., filterable plus condensable PM
2.5
versus filterable PM only). The existing
PM emissions regulations implementing
many current SIPs have focused almost
exclusively on filterable PM at stack
conditions or other elevated
temperatures (e.g., 250
°
F) with little or
no measurement of condensable PM, let
alone filterable PM
2.5
. These
deficiencies exist in spite of the
Agency’s policies and guidance
presented in documents such as the
1987 PM
10
SIP Development
Guideline
48
and the General Preamble
for the Implementation of Title 1 of the
Clean Air Act Amendments of 1990
49
issued in 1992. These documents set
forth Agency policy stating that direct
PM
10
and direct PM
2.5
emissions include
both filterable and condensable
particulate matter. The policies are
reinforced by a 2005 directive from the
CAA Advisory Committee.
50
More to the point, the use of test
methods that quantify only filterable PM
would limit the capability of any
assessment of control measures
available for developing cost effective
strategies to achieve attainment of the
PM
2.5
NAAQS. Examples include an
attainment demonstration that includes
control methodologies for PM
precursors which are likely to result in
a significant decrease in the emissions
of direct PM
2.5
(for example, alkaline
scrubbers to reduce SO
2
emissions) and
incorporate these direct PM
2.5
emissions
reductions in their attainment
demonstration or allow for the use of
these reductions as credits for other
programs.
Some States may decide to measure
and control condensable PM emissions
prior to the end of the transition period.
48
U.S. Environmental Protection Agency. PM–10
SIP Development Guideline. Office of Air Quality
Planning and Standards, Research Triangle Park,
NC. EPA Publication No. EPA–450/2–86–001. June
1987.
49
The General Preamble is available online at
http://www.epa.gov/ttn/oarpg/t1pfpr.html.
50
Clean Air Act Advisory Committee,
Recommendations to the Clean Air Act Advisory
Committee—Phase I and Next Steps, Air Quality
Management Work Group, Environmental
Protection Agency,
http://www.epa.gov/air/caaac/
pdfs/report1-17-05.pdf
, January 2005.
To the extent that a State has the
supporting technical information and
test methods, the State may also assess
the capabilities of current control
technologies, possible modifications to
such technologies, or new technologies
as appropriate relative to control of
condensable PM
2.5
emissions in
developing effective control strategies
and regulations. As an example, a
specific approach for controlling
condensable PM could be a change in
control device operating temperature to
achieve necessary emissions reductions.
We also note that it is important that
implementation of any new or revised
rules and test methods should be
prospective and clearly differentiated
from existing regulations to avoid
confusion over status of compliance
relative to existing PM emissions limits.
4. Sufficiency of Current Baselines
Relative to Direct PM
2.5
for Regulatory
Development
Comment:
Many commenters
indicated that the currently available
baselines for direct PM
2.5
emissions are
not sufficient for States to develop
effective emissions control regulations.
One commenter claimed that States will
need additional information regarding
how to arrive at enforceable PM
2.5
emissions limitations through
application of correlations to existing
PM
10
emissions limitations.
Response:
We agree that State
inventories accounting for direct PM
2.5
emissions are important to the NAAQS
implementation decision-making
process. For example, the current
national emissions inventories have
characterized the contribution of the
condensable PM emissions to range
from 40 to 80 percent of the direct PM
2.5
emissions particularly from combustion
source categories. We also agree in
many cases, the emissions baselines are
not sufficiently representative of
significant direct PM
2.5
contributors to
allow States to develop effective and
enforceable emissions limitations for
sources that may require control of
direct filterable or condensable PM
2.5
emissions in order for States to come
into attainment with the PM
2.5
NAAQS.
We note that States are already
required under the consolidated
emissions reporting rule (CERR) to
report direct PM
2.5
emissions, including
condensable PM, in each inventory
revision. That means that inventories
and associated baselines must address
sources and contributions of direct
PM
2.5
emissions, both filterable and
condensable PM, from individual
sources and groups of sources as well as
for future year projected emissions.
These data are important for the
purposes of calculating emissions
reductions and demonstrating that such
reductions are attributable to the control
measures being implemented.
In taking the process to the next step,
we contend that many current baselines
established using the available direct
filterable and condensable PM
2.5
national industry average emissions
factors (e.g., those found in AP–42 and
WebFIRE,
http://www.epa.gov/ttn/chief/
efpac/index.html
) often are of quality
insufficient to establish effective source-
specific emissions limits. First, national
industry average emissions factors are
subject to significant uncertainties as
they usually represent data from a very
limited number of example facilities in
a category and for a very limited number
of operating conditions. Second, the
available emissions factors databases
may not include direct PM
2.5
emissions
data for specific source types that
appear in some State and local
inventories.
In short, we believe that States should
rely on directly measured emissions
data in developing source category or
pollutant-specific emissions limits for
regulations. This approach is preferable
to the use of these national industry
average emissions factors such as those
found in AP–42. If there are no directly
measured emissions data available from
the subject sources, national average
emissions factors should be used only
with appropriate and significant
adjustments for uncertainty. Based on
our initial study
51
of the uncertainties
associated with national average
emissions factors when applied to site-
specific or rule-development activities,
we would expect multipliers of 0.1 to
3.3 for an A-rated national average
filterable and condensable direct PM
2.5
emissions factors. The level of a
particular multiplier would depend on
how representative of the source
category the applicable emissions factor
is, the quantity of data supporting that
emissions factor, and the specific
application. Determining what
adjustment may apply for a particular
application requires detailed knowledge
of the emissions control variability, the
expected range of operational and
process variability, and the statistical
uncertainty in the measured emissions
data. While more general adjustments to
emissions factors are possible for these
purposes, we believe that the better
approach is to improve and update the
emissions factors used in the database
for a particular area with measured
51
Option Paper 4—Providing Guidance
Regarding The Use Of Emissions Factors For
Purposes Other Than Emissions Inventories,
September 2005,
http://www.epa.gov/ttn/chief/
efpac/projects.html
.
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direct PM
2.5
emissions data. For these
reasons and to allow time for data
collection and analysis, we have
determined the need for a period of
transition for States in developing direct
PM
2.5
emissions reduction strategies.
5. Transition Period
Comment:
Some commenters
suggested that EPA should allow States
to base their initial 2008 SIPs on NO
X
,
SO
2
, and filterable PM or PM
10
(as a
surrogate for filterable PM
2.5
) rather than
require State and local agencies to
develop direct PM
2.5
emissions
regulations immediately. Commenters
suggested that EPA provide a transition
period for sources to adopt SIPs that
address direct PM
2.5
and to apply the
appropriate test methods. The
commenters proposed that during this
transition period, a source should be
able to continue to use Method 5,
Method 17, or whatever method was
used to set the underlying limit
contained in the source’s title V
operating permit. Commenters believe
that such a transition plan must provide
additional time to collect data related to
condensable PM emissions.
Commenters believe that this additional
time is necessary because it is
unrealistic to develop SIP revisions
addressing condensable emissions by
April 2008. Other commenters
suggested that source emissions
inventories used for regulatory decision-
making and identifying regulatory
control measures must be based on
accurate measurements.
Response:
As outlined above, we
agree that a transition period should be
allowed to allow time to resolve and
adopt appropriate testing procedures for
condensable PM emissions, to collect
total (filterable and condensable) PM
2.5
emissions data that are more
representative of the sources in their
areas, and develop effective regulations
for control of direct PM
2.5
, including
condensable PM.
6. Data Collection for Regulatory
Development
Comment:
Several commenters
recommended that EPA should be
responsible for developing data of
emissions from common sources of
direct PM
2.5
.
Response:
We disagree with the
commenters’ recommendation that EPA
should be primarily or solely
responsible for developing baseline data
on common sources of direct PM
2.5
emissions. Commenters are suggesting
that we should collect data
representative of direct PM
2.5
emissions
from source categories potentially
subject to regulation of direct PM
2.5
emissions. Furthermore, they suggest
that we expand or improve the current
compilation of national industry average
emissions factors such as found in AP–
42 and WebFIRE (
http://www.epa.gov/
ttn/chief/efpac/index.html
). Given the
limited extent to which national
industry average emissions factors are
suitable for developing State or local
regulations that set limits on direct
PM
2.5
emissions, we believe that it is
inherent that States instead have
primary responsibility for reviewing and
applying measured emissions data
collected from their sources in
enhancing their current baselines. In
some cases, this will mean that States
and other stakeholders will need to
conduct more focused direct PM
2.5
emissions data collection and improve
relevant emissions factors.
This approach is appropriate for
several reasons. First, we believe that
stakeholders other than EPA are better
equipped to identify specific data needs
and that they have the means to collect
the data. Second, we believe we are
better positioned to provide guidance on
test planning, data collection, and
emissions factors calculations with a
less direct role in data collection and
evaluation. Third, we believe that States
in need of additional information can
also benefit from experience of other
States with similar source types and
who are developing regulations to
implement the NAAQS including the
control of condensable PM. See also the
discussion in section II.L.2.c.1 above on
the currently active collaborative study
to assess direct PM
2.5
emissions
measurement technologies and to
collect updated direct PM
2.5
emissions
data.
7. Developing Effective Regulations for
Direct PM
2.5
, Including Condensable
PM, Emissions
Most current PM regulations focus on
the control and measurement of
filterable PM emissions and do not
account for condensable PM emissions.
At issue are assessing and accounting
for the differences in methodology and
applicable limits when changing to a
program designed to achieve reductions
in PM
2.5
emissions, including
condensable PM.
Comment:
A number of respondents
commented that EPA needs to
promulgate a PM
2.5
test method and
adopt regulatory language that
determines the PM
2.5
limits based on
that promulgated PM
2.5
test method as
soon as possible. Other commenters
suggested that EPA and States have no
choice but to revise the underlying
standard by adopting new monitoring
requirements through a notice and
comment rulemaking. Further, these
commenters indicate that it is essential
that EPA require that no change in a test
method or in methods of monitoring for
determining compliance until such time
as EPA or the permitting agency have
undertaken a notice and comment
process to determine how the emissions
limitations must be revised. A number
of commenters cited specific
components necessary for effective
regulations.
Response:
We agree that notice and
comment rulemaking is appropriate for
establishing effective regulations. As
noted above, we are already undertaking
a study of the available test methods to
determine the need for regulatory
revisions. We also agree that new
regulations limiting direct PM
2.5
emissions must include effective
emissions limitations to the extent that
a State must reduce sources of direct
PM
2.5
. How a State determines to take
such regulatory action depends on the
State’s implementation plan. Regarding
the specific components necessary for
effective regulations, see section O
below on enforcement and compliance
issues.
M. Improving Source Monitoring
a. Background
In the November 1, 2005 proposal, we
discussed a number of actions the EPA
would undertake to improve the
effectiveness of existing and new
regulations with improved source
monitoring provisions. Specifically, we
repeated a plan outlined on January 22,
2004 (69 FR 3202; a
Federal Register
notice describing requirements for
monitoring in operating permits), that
includes a four-part strategy for
improving monitoring of emissions at
the source where necessary through
rulemaking. One element of that plan is
for EPA to develop guidance on how
States can reduce PM
2.5
emissions by
improving source monitoring related to
PM
2.5
emissions limits. We noted that
we expect to describe in such guidance
methods of improving monitoring
frequency or adopting more appropriate
monitoring for States to consider in
developing their PM
2.5
SIPs and to
illustrate the amount of credit that
States could receive in PM
2.5
SIPs for
adopting such improved monitoring. We
suggested that States with areas where
additional reductions are needed to help
the area achieve compliance with the
NAAQS could implement improved
monitoring measures to obtain
additional emissions reductions. We put
forward that State agencies could
receive SIP credits as a result of
enforceable improved monitoring or
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voluntary emissions monitoring
programs meeting EPA voluntary
program policies.
Specific examples of improved
monitoring we outlined included: (1)
Conducting the currently required
monitoring more frequently (i.e.,
increased monitoring frequency), (2)
changing the monitoring technique to a
parameter more closely related to
control of direct or precursor PM
2.5
emissions (i.e., a correlated parametric
monitoring technique), (3) changing the
technique to more measurement of
direct PM
2.5
emissions and PM
2.5
precursors, or (4) a combination of these
improvements. These types of
monitoring improvements could be
conducted for both controlled and
uncontrolled emissions units. The
improved monitoring control measure
would require facilities to pay more
attention to the operation of add-on air
pollution control devices, work
practices, and other control measure
activities. The additional attention will
reduce periods during which control
devices and other control measures do
not operate as intended or required. The
result would be increased emissions
reductions from implementing existing
and new rules.
We discussed a range of currently
applied and new monitoring
technologies. We addressed concerns
we have about the limitations of the
widespread use of visual emissions (VE)
monitoring techniques, such as visible
emissions checks, to show compliance
with PM emissions limits. We noted
particular concerns about VE
approaches, even with frequent
application, having the ability to verify
compliance when the margin of
compliance is small or the ability to
detect relatively significant changes in
emissions control performance. The
other concern we noted about the use of
VE tools is the limited frequency at
which they are conducted. We cited
studies on the availability of continuous
instrumental methods for monitoring
opacity and operational parameters
closely related to PM control levels
including the development of repeatable
correlations between parameter levels
and PM emissions. We noted that PM
continuous emissions monitoring
systems (PM CEMS) technology
provides the opportunity to quantify PM
emissions levels (concentration or
emissions rates). These additional data
provide the source owner/operator with
a level of information that can be useful
for understanding and operating the
process and the control measures in
ways to minimize emissions, improve
operating efficiencies, and reduce
enforcement liabilities. Furthermore, we
noted that this technology will provide
the State with quantitative information
on PM emissions which will help
improve the inventories and to
implement effective control strategies to
meet the NAAQS.
We also discussed at some length
what we believe constitutes improved
monitoring and the potential for
monitoring-related emissions
reductions. We discussed a study of
how these emissions reductions would
be achieved by increasing the
monitoring frequency or improving the
monitoring of an add-on air pollution
control device or other process activity
above the level currently required in
existing rules. The increased frequency
or improved technique would allow
owners or operators to achieve greater
emissions reductions by identifying and
responding more quickly to periods of
ineffective control measure operation.
States could use an improved
monitoring control measure in
regulations or through other means to
reduce emissions levels and receive
credits towards attainment. Specifically,
we cited materials that indicate that
source owners and operators who
increase monitoring frequency could
achieve emissions reductions up to 13
percent and those who improve the
monitoring technique could achieve
emissions reductions up to 15 percent.
States with nonattainment areas in need
of additional reductions to achieve
compliance with the NAAQS could
implement an improved monitoring
measure and develop additional
emissions reductions credits. We
outlined several specific examples.
In order to inform our improved
monitoring guidance development
efforts, we used the 2005 proposal to
solicit specific comments on (1) how
potentially inadequate source
monitoring in certain SIPs could be
improved; (2) how improved PM
2.5
monitoring relates to title V monitoring;
(3) whether instrumental techniques are
more appropriate than visual emissions
(VE) techniques for monitoring
compliance with PM emissions limits;
and (4) a basis for determining whether
improved monitoring would be effective
and under what conditions should be
required. We also requested comment
on the feasibility of monitoring of co-
pollutant control measures and
requested examples of improved
monitoring for any applications.
b. Final Rule
We maintain that improved
monitoring is critical to implementing
the PM
2.5
direct and precursor emissions
reductions programs. We also believe
that improving monitoring both in terms
of increasing data collection and
analysis frequency and in measuring the
pollutant of interest more directly will
accomplish several important and
advantageous outcomes. First, improved
monitoring will improve verification of
compliance and assurance of the
intended emissions reductions. Second,
improved monitoring can provide
additional emissions reductions through
quicker detection and correction of
control measure problems. Third,
improved monitoring can improve
operating efficiencies that often result in
cost savings to the facility exceeding the
cost of the monitoring. We will continue
to evaluate the effects of improved
monitoring on emissions reductions and
ways to quantify the benefits associated
with improved monitoring.
We intend to move forward with
developing and providing additional
technical and informational materials
regarding technologies constituting
improved monitoring and for
developing regulations with improved
monitoring. These materials may also
include guidance and tools for
establishing emissions reductions
credits and the economic benefits
associated with improved monitoring.
As noted in section L above, we also
reaffirm our policy that effective
regulations must include certain
elements that define applicable
emissions limitations, the testing and
monitoring requirements, and
compliance, reporting, and corrective
action obligations.
c. Comments and Responses
We expected to receive practical
advice concerning improved PM
2.5
source emissions monitoring methods
and field-tested examples. Instead,
commenters focused on (1) critiquing
PM CEMS technology (2) insisting that
improving monitoring changes
stringency of existing rules and requires
rulemaking, and (3) critiquing the
theoretical study linking emissions
reductions with improved monitoring.
1. Currently Available PM CEMS for
Monitoring Direct PM
2.5
Emissions
Comment:
Commenters noted that
because currently available PM CEMS
measure filterable PM at stack
conditions or at other elevated
temperatures, the instruments do not
measure the condensable portion of
PM
2.5
.
Response:
We agree with this
comment relative to PM CEMS in use to
date and the ability to detect
condensable PM. PM CEMS as applied
today can be calibrated to measure
filterable PM
2.5
emissions with very
good sensitivity and repeatability. Note
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that we are aware of a number of PM
CEMS vendors developing devices
relying on much the same technology
but modified to measure condensable
PM. Further, we are aware of at least
one manufacturer offering a PM CEMS
applicable to stationary sources that also
complies with ASTM requirements for
mobile source emissions monitoring.
We also believe that monitoring for
filterable PM
2.5
will be as important in
some cases as monitoring for
condensable PM and that PM CEMS in
use today are markedly better at
monitoring PM emissions than other
frequently used monitoring approaches.
We realize that PM CEMS represent
just one of a range of monitoring options
that constitute improvements over the
current monitoring. For instance, we
believe that improved monitoring would
include replacing current periodic VE
measurements or daily recording of
pressure drop of fabric filters with
continuous bag leak detectors. We know
of projects (e.g., ASTM committee work)
for continuing the development of
optical, as well as electromagnetic,
monitoring tools to increase sensitivity
and cost-effectiveness. Such monitoring
would increase monitoring frequency
and would yield data much more
closely related to and more sensitive to
control device operation than most
currently applied monitoring. To the
extent that condensable PM control is
critical in implementing a regulation,
we believe that monitoring must address
that need. We will continue to collect
and also provide information on source
monitoring approaches that are
improvements over current methods in
both frequency and representativeness
relative to implementing PM
2.5
emissions control strategies.
2. Status of Guidance Relative to
Regulations
Comment:
A significant majority of
commenters suggested that improving
monitoring in an existing regulation
increases its stringency and requires
notice and comment rulemaking, not
guidance. Just one commenter suggested
guidance could be developed and used.
Response:
There are two aspects to
the comments on this issue. One is
whether improved monitoring would
change source operations. We agree
with the commenters that increasing the
frequency of data collection or
providing data more directly related to
the pollutant of concern with improved
monitoring could result in changes in
how a facility is operated relative to
compliance. We disagree with
commenters that such changes in
process operation resulting from
improved monitoring constitute an
increase in a regulation’s stringency
with respect to compliance. First, as
mentioned in the preamble to the
Credible Evidence rule (62 FR 8326,
February 24, 1997), an emissions
standard’s required stringency is
unaffected by the frequency of
monitoring given no decrease in
averaging time or emissions limitation.
Secondly, data from improved
monitoring will provide a facility
operator better information on control
measure performance more quickly and
allow for reducing the duration and the
number of periods that may lead to
compliance problems. Reducing the
duration of excess emissions periods,
for example, with improved monitoring
is not an increase in regulatory
stringency but a decrease in
enforcement liability.
The second aspect to the comment is
questioning whether we can issue
technical information about improved
monitoring as guidance without
applying it to a
Federal Register
notice
and comment process. We disagree with
commenters who believe that our
developing and disseminating technical
resource information is limited to notice
and comment rulemaking. We note that
making technical and other information
materials available to the public, states,
and industry is an important Agency
function. There are many examples of
the Agency dispensing such information
including the Monitoring Knowledge
Base (
http://cfpub.epa.gov/mkb/
) that
provides just such information on
improved monitoring. On the other
hand, we agree with commenters that
any significant change to an existing
regulation, including the addition of
new monitoring requirements, would be
subject to notice and comment
rulemaking. To the extent that States
determine the need for changing
existing or developing new regulations,
public notice and comment rulemaking
is appropriate. Our role in developing
technical resources and information
informing the states in developing those
revised or new regulations does not
require, nor should be subject to the
rulemaking process. In that light, we
recognize the value in obtaining and
responding to public comments and
suggestions on informative technical
materials. Further, we believe
rulemaking is not necessarily required
for source owners or operators who
volunteer to participate in an optional
improved monitoring program, such as
the one mentioned in the proposal. That
program seeks to provide SIP credits to
States where source owners or operators
agree to improve their PM monitoring
approaches. We plan on continuing to
prepare and offer non-regulatory
incentives for source owners and
operators who volunteer to improve
existing monitoring.
3. Study of Improved Monitoring-
Induced Emissions Reductions
Comment:
Commenters recommended
that the proposal’s theoretical study
showing PM emissions reductions from
the use of improved monitoring needs to
be validated with field data.
Response:
We agree with commenters
that one should base any costs and
benefits findings as well as validating
the approach on available data. To the
extent that this applies to assessing the
benefits of emissions reductions
achieved through improved monitoring,
we requested that commenters provide
data or leads to other information or to
other alternatives that show how
improved monitoring yields emissions
reductions and ways to quantify
possible PM credits for SIPs. In fact, we
are disappointed that commenters failed
to provide these data or examples of
other approaches. As resources allow,
we will investigate opportunities for
field validation of the theoretical study,
as well as other means to offer
incentives for use of improved
monitoring.
N. Guidance Specific to Tribes
a. Background
The proposal set forth guidance for
Tribes regarding various aspects of air
quality management, and this guidance
remains largely the same as described in
the section below.
b. Final Rule
The 1998 Tribal Authority Rule (TAR)
(40 CFR part 49), which implements
section 301(d) of the CAA, gives Tribes
the option of developing tribal
implementation plans (TIPs).
Specifically, the TAR provides for the
Tribes to be treated in the same manner
as a State in implementing sections of
the CAA. However, Tribes are not
required to develop implementation
plans. The EPA determined in the TAR
that it was inappropriate to treat Tribes
in a manner similar to a State with
regard to specific plan submittal and
implementation deadlines for NAAQS-
related requirements, including, but not
limited to, such deadlines in CAA
sections 110(a)(1), 172(a)(2), 182, 187,
and 191. (Add footnote) See 40 CFR
49.4(a). In addition, EPA determined it
was not appropriate to treat tribes
similarly to states with respect to
provisions of the CAA requiring as a
condition of program approval the
demonstration of criminal enforcement
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authority or providing for the delegation
of such criminal enforcement authority.
See 40 CFR 49.4(g). To the extent a tribe
is precluded from asserting criminal
enforcement authority, the Federal
government will exercise primary
criminal enforcement responsibility. See
40 CFR 49.8. In such circumstances,
tribes seeking approval for CAA
programs provide potential investigative
leads to an appropriate federal
enforcement agency. (end footnote)
If a Tribe elects to do a TIP, we will
work with the Tribe to develop an
appropriate schedule which meets the
needs of the Tribe, and which does not
interfere with the attainment of the
NAAQS in other jurisdictions. The
Tribe developing a TIP can work with
the EPA Regional Office on the
appropriateness of addressing RFP and
other substantive SIP requirements that
may or may not be appropriate for the
Tribe’s situation.
The TAR indicates that EPA is
ultimately responsible for implementing
CAA programs in Indian country, as
necessary and appropriate, if Tribes
choose not to implement those
provisions. For example, an unhealthy
air quality situation in Indian country
may require EPA to develop a FIP to
reduce emissions from sources on the
reservation. In such a situation, EPA, in
consultation with the Tribe and in
consideration of their needs, would
work to ensure that the NAAQS are met
as expeditiously as practicable.
Likewise, if we determine that sources
in Indian country could interfere with a
larger nonattainment area meeting the
NAAQS by its attainment date, we
would develop a FIP for those sources
in consultation with the Tribe, as
necessary or appropriate.
The TAR also provides flexibility for
the Tribe in the preparation of a TIP to
address the NAAQS. If a Tribe elects to
develop a TIP, the TAR offers flexibility
to Tribes to identify and implement on
a Tribe-by-Tribe, case-by-case basis only
those CAA programs or program
elements needed to address their
specific air quality problems. In the
proposed Tribal rule, we described this
flexible implementation approach as a
modular approach. Each Tribe may
evaluate the particular activities,
including potential sources of air
pollution within the exterior boundaries
of its reservation (or within non-
reservation areas for which it has
demonstrated jurisdiction), which cause
or contribute to its air pollution
problem. A Tribe may adopt measures
for controlling those sources of PM
2.5
-
related emissions, as long as the
elements of the TIP are reasonably
severable from the package of elements
that can be included in a whole TIP. A
TIP must include regulations designed
to solve specific air quality problems for
which the Tribe is seeking EPA
approval, as well as a demonstration
that the Tribal air agency has the
authority from the Tribal government to
develop and run their program, the
capability to enforce their rules, and the
resources to implement the program
they adopt. In addition, the Tribe must
receive an eligibility determination from
EPA to be treated in the same manner
as a State and to receive authorization
from EPA to run a CAA program.
The EPA would review and approve,
where appropriate, these partial TIPs as
one step of an overall air quality plan to
attain the NAAQS. A Tribe may step in
later to add other elements to the plan,
or EPA may step in to fill gaps in the
air quality plan as necessary or
appropriate. In approving a TIP, we
would evaluate whether the plan
interferes with the overall air quality
plan for an area when Tribal lands are
part of a multi-jurisdictional area.
Because many of the nonattainment
areas will include multiple
jurisdictions, and in some cases both
Tribal and State jurisdictions, it is
important for the Tribes and the States
to work together to coordinate their
planning efforts. States need to
incorporate Tribal emissions in their
base emission inventories if Indian
country is part of an attainment or
nonattainment area. Tribes and States
need to coordinate their planning
activities as appropriate to ensure that
neither is adversely affecting attainment
of the NAAQS in the area as a whole.
c. Comments and Responses
No public comments were received on
this section.
O. Enforcement and Compliance
a. Background
The proposed rule included a
discussion of the specific requirements
that must be addressed in order for SIP
regulations to be enforceable.
b. Final Rule
The final rule includes similar
guidance on enforceable SIP regulations,
with some additional discussion about
specific elements that must be
addressed regarding compliance testing
and compliance monitoring. (Note that
enforceable SIP regulations may address
these key elements in different ways
depending on the type of source
category being regulated.)
In general, for a SIP regulation to be
enforceable, it must clearly spell out
which sources or source types are
subject to its requirements and what its
requirements (e.g., emission limits,
work practices, etc.) are. The regulation
also needs to specify the time frames
within which these requirements must
be met, and must definitively state
recordkeeping and monitoring
requirements appropriate to the type of
sources being regulated. The
recordkeeping and monitoring
requirements must be sufficient to
enable the State or EPA to determine
whether the source is complying with
the emission limit on a continuous
basis. An enforceable regulation must
also contain test procedures in order to
determine whether sources are in
compliance.
Complete and effective regulations
that ensure compliance with an
applicable emissions limit must include
requirements for both performance
testing of emissions and ongoing
monitoring of the compliance
performance of control measures. SIP
regulations must include the following
critical elements of regulatory
compliance testing:
Indicator(s) of compliance—the
pollutant or pollutants of interest (e.g.,
filterable PM
2.5
plus condensable PM
2.5
)
and the applicable measurable units for
expressing compliance (e.g., ng/J of heat
input, lb/hr);
Test method—reference to a
specific EPA or other published set of
sample collection and analytical
procedures, equipment design and
performance criteria, and the
calculations providing data in units of
the indicator of compliance (see section
II.L. below for descriptions of available
and potential improved test methods);
Averaging time—the minimum
length of each required test run and the
requirement to average the results of the
test runs (e.g., three runs) representing
a specified period of time (e.g., 8 hours);
and
Frequency—the maximum time
between conduct of emissions or
performance tests (e.g., within 30 days
of facility start-up and once each
successive quarter, every 6-month
period, yearly).
In order to be complete with regard to
compliance monitoring provisions, SIP
regulations must include the following
critical elements:
Indicator(s) of performance—the
parameter or parameters measured or
observed for demonstrating proper
operation of the pollution control
measures or compliance with the
applicable emissions limitation or
standard. Indicators of performance may
include direct or predicted emissions
measurements, process or control device
(and capture system) operational
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parametric values that correspond to
compliance with efficiency or emissions
limits, and recorded findings of
verification of work practice activities,
raw material or fuels pollutant content,
or design characteristics. Indicators may
be expressed as a single maximum or
minimum value, a function of process
variables (e.g., within a range of
pressure drops), a particular operational
or work practice status (e.g., a damper
position, completion of a waste recovery
task), raw material or fuel pollutant
content, or an interdependency between
two or more variables;
Measurement technique—the
means used to gather and record
information of or about the indicators of
performance. The components of the
measurement technique include the
detector type or analytical method,
location and installation specifications,
inspection procedures, and quality
assurance and quality control measures.
Examples of measurement approaches
include continuous emissions
monitoring systems, continuous opacity
monitoring systems, continuous
parametric monitoring systems,
performance testing, vendor or
laboratory analytical data, and manual
inspections and data collection that
include making records of process
conditions, raw materials or fuel
specifications, or work practices;
Monitoring frequency—the number
of times to obtain and record monitoring
data over a specified time interval.
Examples of monitoring frequencies
include at least one data value every 15
minutes for continuous emissions or
parametric monitoring systems, at least
every 10 seconds for continuous opacity
monitoring systems, upon receipt or
application of raw materials or fuel to
the process, and at least once per
operating day (or week, month, etc.) for
performance testing, work practice
verification, or equipment design
inspections; and
Averaging time—the period over
which to average and use data to verify
compliance with the emissions
limitation or standard or proper
operation of the pollution control
measure. Examples of averaging time
include a 3-hour average in units of the
emissions limitation, a 30-day rolling
average emissions value, a daily average
of a control device operational
parametric range, periodic (e.g.,
monthly, annual) average of raw
materials or fuel pollutant content, and
an instantaneous alarm.
These regulatory elements are
essential for effective implementation of
the rules and clear and enforceable
applicable requirements. We believe
that approval of regulations
implementing the SIPs must ensure that
these critical elements are present and
clearly defined to be approvable. We
reiterate that the compliance
obligations, including emissions limits
and other applicable requirements, must
be representative of and accountable to
the assumptions used in the SIP
demonstration. This accountability
includes the ability to transfer the
applicable regulatory requirements to an
operating permit subject to EPA and
public review.
Under the Title V regulations, sources
have an obligation to include in their
Title V permit applications all
emissions for which the source is major
and all emissions of regulated air
pollutants. The definition of regulated
air pollutant in 40 CFR 70.2 includes
any pollutant for which a NAAQS has
been promulgated, which would
include both PM
10
and PM
2.5
. To date,
some permitted entities have been using
PM
10
emissions as a surrogate for PM
2.5
emissions. Upon promulgation of this
rule, EPA will no longer accept the use
of PM
10
as a surrogate for PM
2.5
. Thus,
sources will be required to include their
PM
2.5
emissions in their Title V permit
applications, in any corrections or
supplements to these applications, and
in applications submitted upon
modification and renewal.
52
The degree
of quantification of PM
2.5
emissions
required will depend on the types of
determinations that a permitting
authority needs to address for a
particular source, the requirements of
title V, and the informational needs and
requirements of the particular State in
question. Sources must continue to
describe their PM
10
emissions in their
applications as indicated above because
the original PM
10
NAAQS remains in
effect.
c. Comments and Responses
Comment:
One commenter disagreed
with language in the preamble to the
proposal regarding Title V permitting
requirements and the requirement to
include various emissions information
in title V permit applications. As
described in 40 CFR 70.5(c)(3)(i) and
71.5(c)(3)(i), sources are required to
include in their permit applications all
emissions for which the source is major
and all emissions of regulated air
pollutants. In the preamble to the
proposal, the EPA stated that in the past
some permitted entities have been using
PM
10
emissions as a surrogate for PM
2.5
emissions in permit applications, or in
corrections or supplements to
52
See 40 CFR 70.5(c)(3)(i), 70.5(b), and
70.7(a)(1)(i); 40 CFR 71.5(c)(3)(i), 71.5(b), and
71.7(a)(1)(i).
applications. The EPA stated that upon
promulgation of this rule, the EPA will
no longer accept the use of PM
10
as a
surrogate for PM
2.5
.
The commenter disagreed with
language in the proposal stating that
sources would be required to detail or
quantify PM
2.5
emissions in permit
applications, or in corrections or
supplements to applications. The
commenter asserts that the inclusion of
PM
2.5
emissions information is required
in a Title V permit application only if
there is an applicable requirement in
existence for which the source’s
applicability is in question and cited to
various examples from the
memorandum entitled ‘‘White Paper for
Streamlined Development of Part 70
Permit Applications,’’ from Lydia N.
Wegman, Deputy Director, Office of Air
Quality Planning and Standards, to Air
Division Directors, Regions I–X, dated
July 10, 1995.
Response:
The commenter is
concerned that as a result of this rule all
applications (including initial,
modification, and renewal applications)
will need to include a quantification of
PM
2.5
emissions, and that a State will
request that every source supplement or
correct any existing title V application
in order to provide an estimation of
PM
2.5
emissions at the source.
The EPA is not implying that this is
the case. The degree of quantification of
PM
2.5
emissions required in an
application (including an initial,
modification, or renewal application), or
in a correction or supplement to an
existing application, depends on the
types of determinations that a
permitting authority needs to address
for a particular source, the requirements
of title V, and the informational needs
and requirements of the particular State
in question. For example, if a source
which emits PM
2.5
emissions has
submitted a title V application, but a
draft permit has not yet been issued,
then the source is required to submit
information relative to the
quantification of its PM
2.5
emissions if
such information is needed or requested
and it has not previously submitted
such information. See 40 CFR 70.5(b)
and 71.5(b).
Circumstances necessitating the
quantification of PM
2.5
emissions and
the submittal of this information
include: (1) Determining all of the
pollutants for which a source is major;
(2) determining whether an applicable
requirement or program applies, e.g.,
determining the applicability of a SIP
requirement or a PSD or nonattainment
NSR program, etc.; or (3) determining
what fees a source owes a permitting
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authority as a result of considering
PM
2.5
emissions.
In all circumstances, however, a State
may require that a source quantify its
PM
2.5
emissions information in an
application, supplement, or correction,
even if it is not needed for the particular
determination at issue. The State, for
example, may choose to obtain this
information for air quality planning
purposes, developing emission
inventories, or for other purposes
related to its air quality management
goals. Requesting such emissions
information is an option for any title V
permitting authority.
The ‘‘White Paper for Streamlined
Development of Part 70 Permit
Applications,’’ referenced by the
commenter, was a confirmation of EPA
policy with respect to the fact that the
specificity of emissions quantification
can vary significantly, depending on the
circumstances of a particular source. It
is also important to note that this
guidance document is a statement
regarding the range of discretion
available to permitting authorities in
implementing the emissions
quantification requirement, not a
restriction of that discretion to
minimum practices. Thus, States can
implement this guidance document at
their option, either in part or in its
entirety.
In summary, the purpose of the
statements made in the preamble to the
proposal was to notify sources that as of
the promulgation of this final rule, the
EPA will no longer accept the use of
PM
10
emissions information as a
surrogate for PM
2.5
emissions
information
53
given that both pollutants
are regulated by a National Ambient Air
Quality Standard and therefore are
considered regulated air pollutants. See
the definition of regulated air pollutant
in 40 CFR 70.2 and 71.2.
54
The degree
of quantification of PM
2.5
emissions now
required in an application (including an
initial, modification, or renewal
application), or provided in a correction
or supplement to an existing
application, will depend on the types of
determinations that a permitting
authority needs to address for a
53
For background information on issues
surrounding implementation of the PM
2.5
NAAQS,
see the EPA memo entitled ‘‘Implementation of
New Source Review Requirements in PM
2.5
Nonattainment Areas,’’ from Stephen D. Page,
Director, Office of Air Quality Planning and
Standards, to Regional Air Directors, Regions I–X,
dated April 5, 2005.
54
For background information on regulated air
pollutants, see the EPA memo entitled ‘‘Definition
of Regulated Air Pollutant for Purposes of Title V,’’
from Lydia N. Wegman, Deputy Director, Office of
Air Quality Planning and Standards, to Air Division
Directors, Regions I–X, dated April 26, 1993.
particular source, the requirements of
title V, and the informational needs and
requirements of the particular State in
question.
P. Emergency Episodes
a. Background
In the proposal, we noted that subpart
H of 40 CFR part 51 specifies
requirements for SIPs to address
emergency air pollution episodes and
for preventing air pollutant levels from
reaching levels determined to cause
significant harm to the health of
persons. We noted that we anticipate
proposing a separate rulemaking in the
future to update portions of that rule.
The preamble to the proposal
b. Final Rule
We have not yet proposed any rule
revision related to emergency episodes.
c. Comments and Responses
We received no comments on this
section of the proposal.
Q. Ambient Monitoring
a. Background
Ambient air quality monitoring for
PM
2.5
plays an important role in
identifying areas violating the NAAQS,
control strategy development, and
tracking progress to attainment. We
indicated in the proposal that States are
required to monitor PM
2.5
mass
concentrations using Federal Reference
Method devices to determine
compliance with the NAAQS.
55
We did
not propose any revisions to current
ambient monitoring requirements listed
in 40 CFR part 58. Currently, there are
more than 1200 FRM monitors located
across the country. States will need to
maintain monitors in designated
nonattainment areas in order to track
progress toward attainment and
ultimately determine whether the area
has attained the PM
2.5
standards.
In addition to the FRM network, EPA
and the States have also deployed more
than 250 speciation monitoring sites
around the country to sample for
chemical composition of PM
2.5
. The data
provided from these speciation monitors
are invaluable in identifying
contributing source categories and
developing control strategies to reach
attainment. Source apportionment and
other receptor modeling techniques rely
on the detailed data on species, ions,
and other compounds obtained from
chemical analysis. Analyses of rural
versus urban sites to identify which
PM
2.5
components comprise the ‘‘urban
55
The PM
2.5
monitoring regulations are located at
40 CFR part 58.
excess’’ (urban minus rural levels)
portion of PM
2.5
mass also rely on data
from speciation monitors. The EPA
encourages states to expand their data
analysis efforts using the wealth of
information provided from the
speciation monitoring network.
b. Final Rule
There is no change from the proposal.
We are not promulgating any additional
monitoring requirements as part of this
rulemaking. Revised monitoring
regulations were issued in 2006 along
with the revised PM NAAQS.
c. Comments and Responses
There were no comments on this
section.
III. Statutory and Executive Order
Reviews
A. Executive Order 12866: Regulatory
Planning and Review
Under section 3(f)(1) of Executive
Order (EO) 12866 (58 FR 51735, October
4, 1993), this action is an ‘‘economically
significant regulatory action.’’
Implementation of the PM
2.5
NAAQS is
likely to have an annual effect on the
economy of $100 million or more.
Accordingly, EPA submitted this action
to the Office of Management and Budget
(OMB) for review under EO 12866 and
any changes made in response to OMB
recommendations have been
documented in the docket for this
action. For clarity, we note that the
estimated costs and benefits of
implementing the 1997 PM
2.5
NAAQS
are not created by this rule, because the
Clean Air Act requires state
implementation of the 1997 PM
2.5
standards (through state development of
plans with enforceable requirements for
sources) on a statutory timetable
regardless of whether EPA issues this
rule interpreting the statutory
requirements. The rule reflects the
statutory requirements.
As part of the ‘‘Regulatory Impact
Analysis for Particulate Matter National
Ambient Air Quality Standards
(September 2006),’’ EPA prepared an
assessment of the estimated costs and
benefits associated with attaining the
1997 PM
2.5
NAAQS in 2015,
incremental to currently promulgated
federal and state programs including for
example the Clean Air Interstate Rule,
the Nonroad Diesel Rule, and other
programs. This analysis is included as
Appendix A of the report and is
available in the docket for this action
and on EPA’s Web site at:
http://
www.epa.gov/ttn/ecas/regdata/RIAs/
Appendix%20A—
2015%20Analysis.pdf.
This illustrative
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analysis finds that the estimated
monetized benefits of attaining the 1997
standards in 2015 are between $43
billion and $97 billion annually, and the
estimated monetized costs are $6.7
billion annually. The RIA states: ‘‘Note
that because this analysis was intended
to compare costs and benefits of
attaining alternative standards by fixed
dates, it did not attempt to identify for
each designated PM
2.5
area measures
that may be needed to meet subpart 1
Clean Air Act requirements, such as
reasonably available measures and
attainment as expeditiously as
practicable. It is expected that
additional costs and benefits will begin
to accrue in earlier years as states
comply with these requirements.’’ (RIA,
p. 1–4)
B. Paperwork Reduction Act
The information collection
requirements in this rule have been
submitted for approval to the Office of
Management and Budget (OMB) under
the
Paperwork Reduction Act,
44 U.S.C.
3501
et seq.
In a separate
Federal
Register
notice published today, EPA is
requesting comment on the information
collection requirements of this rule. The
information collection requirements are
not enforceable until OMB approves
them.
The data collected from the State or
local air agency respondents will
include the required SIP elements
prescribed in CAA sections 110 and part
D, subpart 1 of title I for Implementation
plans and the requirements in this
Implementation Rule (40 CFR 51.1000–
51.1012). The PM
2.5
SIP will contain
rules and other requirements designed
to achieve the NAAQS by the deadlines
established under the CAA, and it also
contains a demonstration that the State’s
requirements will in fact result in
attainment. The SIP must meet the
requirements in subpart 1 to adopt
RACM, RACT, and provide for RFP
toward attainment for the period prior
to the area’s attainment date.
The Agency anticipates additional
administrative burden during the 3 year
period of the ICR for State governments
and the Agency of 630,000 hours and
69,300 hours, respectively. Fifty percent
of the hours are expended in the first
year with the remainder evenly divided
between the second and third years of
the ICR period. Tribes are not required
to conduct attainment demonstrations
or submit the RFP, RACT, or RACM
requirements.
The present value of the total
additional costs for State government
respondents is estimated at $33.4
million for the 3 year period. On an
equivalent annual basis that is $12.7
million per year during the 3 year
period of the ICR. The present value of
the Agency administrative cost burden
is estimated at $3.7 million dollars for
the 3 year period. This is equivalent to
an equal annual stream of costs of $1.4
million per year during the three year
period. Burden means the total time,
effort, or financial resources expended
by persons to generate, maintain, retain,
or disclose or provide information to or
for a Federal agency. This includes the
time needed to review instructions;
develop, acquire, install, and utilize
technology and systems for the purposes
of collecting, validating, and verifying
information, processing and
maintaining information, and disclosing
and providing information; adjust the
existing ways to comply with any
previously applicable instructions and
requirements; train personnel to be able
to respond to a collection of
information; search data sources;
complete and review the collection of
information; and transmit or otherwise
disclose the information.
An agency may not conduct or
sponsor, and a person is not required to
respond to a collection of information
unless it displays a currently valid OMB
control number. The OMB control
numbers for EPA’s regulations in 40
CFR are listed in 40 CFR part 9. When
this ICR is approved by OMB, the
Agency will publish a technical
amendment to 40 CFR part 9 in the
Federal Register
to display the OMB
control number for the approved
information collection requirements
contained in this final rule.
C. Regulatory Flexibility Act
The Regulatory Flexibility Act (RFA)
generally requires an agency to prepare
a regulatory flexibility analysis of any
rule subject to notice and comment
rulemaking requirements under the
Administrative Procedure Act or any
other statute unless the agency certifies
that the rule will not have a significant
economic impact on a substantial
number of small entities. Small entities
include small businesses, small
organizations, and small governmental
jurisdictions.
For purposes of assessing the impacts
of this final action on small entities,
small entity is defined as: (1) A small
business as defined by the Small
Business Administration’s (SBA)
regulations at 13 CFR 121.201; (2) a
small governmental jurisdiction that is a
government of a city, county, town,
school district, or special district with a
population of less than 50,000; or (3) a
small organization that is any not-for-
profit enterprise that is independently
owned and operated and is not
dominant in its field.
After considering the economic
impacts of this final rule on small
entities, I certify that this action will not
have a significant economic impact on
a substantial number of small entities
and it is not necessary to prepare a
regulatory flexibility analysis in
conjunction with this final rule. The
final rule governing SIPs will not
directly impose any requirements on
small entities. Rather, this rule
interprets the obligations established in
the CAA for States to submit
implementation plans in order to attain
the PM
2.5
NAAQS.
D. Unfunded Mandates Reform Act
Title II of the Unfunded Mandates
Reform Act of 1995 (UMRA), Public
Law 104–4, establishes requirements for
Federal agencies to assess the effects of
their regulatory actions on State, local,
and Tribal governments and the private
sector. Under section 202 of the UMRA,
EPA generally must prepare a written
statement, including a cost-benefit
analysis, for proposed and final rules
with ‘‘Federal mandates’’ that may
result in expenditures to State, local,
and tribal governments, in the aggregate,
or to the private sector, of $100 million
or more in any 1 year. Before
promulgating an EPA rule for which a
written statement is needed, EPA is
required by section 205 of the UMRA to
identify and consider a reasonable
number of regulatory alternatives, and
adopt the least costly, most cost-
effective or least burdensome alternative
that achieves the objectives of the rule.
The provisions of section 205 do not
apply when they are inconsistent with
applicable law. Moreover, section 205
allows EPA to adopt an alternative other
than the least costly, most cost-effective
or least burdensome alternative if the
Administrator publishes with the final
rule an explanation why that alternative
was not adopted. Before EPA establishes
any regulatory requirements that may
significantly or uniquely affect small
governments, including Tribal
governments, it must have developed
under section 203 of the UMRA a small
government agency plan. The plan must
provide for notifying potentially
affected small governments, enabling
officials of affected small governments
to have meaningful and timely input in
the development of EPA regulatory
proposals with significant Federal
intergovernmental mandates, and
informing, educating, and advising
small governments on compliance with
the regulatory requirements.
This rule contains no Federal
mandate that may result in expenditures
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of $100 million or more for State, local,
and Tribal governments, in the
aggregate, or the private sector in any 1
year. The estimated administrative
burden hours and costs associated with
implementing the PM
2.5
NAAQS are
estimated in the ICR for this rule. The
estimated costs presented there for
States totals $33.4 million for a three-
year period. Thus, this rule is not
subject to the requirements of section
202 and 205 of the UMRA. The EPA
consulted with governmental entities
affected by this rule and has determined
that this rule contains no regulatory
requirements that may significantly or
uniquely affect small governments,
including Tribal governments.
The CAA imposes the obligation for
States to submit SIPs to implement the
PM
2.5
NAAQS. In this rule, EPA is
merely providing an interpretation of
those requirements. However, even if
this rule did establish an independent
requirement for States to submit SIPs, it
is questionable whether a requirement
to submit a SIP revision would
constitute a Federal mandate in any
case. The obligation for a State to submit
a SIP that arises out of section 110 and
section 172 (part D) of the CAA is not
legally enforceable by a court of law,
and at most is a condition for continued
receipt of highway funds. Therefore, it
is possible to view an action requiring
such a submittal as not creating any
enforceable duty within the meaning of
section 421(5)(9a)(I) of UMRA (2 U.S.C.
658(a)(I)). Even if it did, the duty could
be viewed as falling within the
exception for a condition of Federal
assistance under section 421(5)(a)(i)(I) of
UMRA (2 U.S.C. 658(5)(a)(i)(I)).
E. Executive Order 13132: Federalism
Executive Order 13132, entitled
‘‘Federalism’’ (64 FR 43255, August 10,
1999), requires EPA to develop an
accountable process to ensure
‘‘meaningful and timely input by State
and local officials in the development of
regulatory policies that have Federalism
implications.’’ ‘‘Policies that have
Federalism implications’’ is defined in
the Executive Order to include
regulations that have ‘‘substantial direct
effects on the States, on the relationship
between the national government and
the States, or on the distribution of
power and responsibilities among the
various levels of government.’’
At the time of proposal, EPA
concluded that the proposed rule would
not have any federalism implications.
The EPA stated that the proposed rule
would not have substantial direct effects
on the States, on the relationship
between the national government and
the States, or on the distribution of
power and responsibilities among the
various levels of government, as
specified in Executive Order 13132. The
CAA establishes the scheme whereby
States take the lead in developing plans
to meet the NAAQS. This rule clarifies
the statutory obligations of States in
implementing the PM
2.5
NAAQS.
However, EPA recognized that States
would have a substantial interest in this
rule and any corresponding revisions to
associated SIP requirements.
Therefore, in the spirit of Executive
Order 13132, and consistent with EPA
policy to promote communications
between EPA and State and local
governments, EPA held a number of
calls with representatives of State and
local air pollution control agencies and
hosted a public hearing in Washington,
DC in November 2005. The EPA
considered the comments from State
and local governments in developing
the final rule.
EPA concludes that this final rule
does not have federalism implications,
for the reasons proposed. The final rule
will not modify the relationship of the
States and EPA for purposes of
developing programs to implement the
NAAQS. As noted above in section D on
UMRA, this rule does not impose
significant costs on State and local
governments. (EPA estimates the costs
to States to implement the PM
2.5
NAAQS to be $33.4 million.) Thus,
Executive Order 13132 does not apply
to this rule.
F. Executive Order 13175: Consultation
and Coordination With Indian Tribal
Governments
Executive Order 13175, entitled
‘‘Consultation and Coordination with
Indian Tribal Governments’’ (65 FR
67249, November 9, 2000), requires EPA
to develop an accountable process to
ensure ‘‘meaningful and timely input by
Tribal officials in the development of
regulatory policies that have Tribal
implications.’’ This final rule does not
have ‘‘Tribal implications’’ as defined in
Executive Order 13175. This rule
concerns the requirements for State and
tribal implementation plans for
attaining the PM
2.5
air quality standards.
The CAA provides for States to develop
plans to regulate emissions of air
pollutants within their jurisdictions.
The Tribal Air Rule (TAR) under the
CAA gives Tribes the opportunity to
develop and implement CAA programs
such as programs to attain and maintain
the PM
2.5
NAAQS, but it leaves to the
discretion of the Tribe the decision of
whether to develop these programs and
which programs, or appropriate
elements of a program, they will adopt.
Although Executive Order 13175 does
not apply to this rule, EPA did reach out
to Tribal leaders and environmental
staff in developing this rule. From
2001–2004, the EPA supported a
National Designations Workgroup to
provide a forum for tribal professionals
to give input to the designations
process. In 2006, EPA supported a
national ‘‘Tribal Air call’’ which
provides an open forum for all Tribes to
voice concerns to EPA about the
NAAQS implementation process,
including the PM
2.5
NAAQS. In these
meetings, EPA briefed call participants
and Tribal environmental professionals
gave input as the rule was under
development. Furthermore, in December
2005, EPA sent individualized letters to
all federally recognized Tribes about the
proposal to give Tribal leaders the
opportunity for consultation.
This final rule does not have Tribal
implications as defined by Executive
Order 13175. It does not have a
substantial direct effect on one or more
Indian Tribes, since no Tribe has
implemented a CAA program to attain
the PM
2.5
NAAQS at this time. The EPA
notes that even if a Tribe were
implementing such a plan at this time,
while the rule might have Tribal
implications with respect to that Tribe,
it would not impose substantial direct
costs upon it, nor would it preempt
Tribal law.
Furthermore, this rule does not affect
the relationship or distribution of power
and responsibilities between the Federal
government and Indian Tribes. The
CAA and the TAR establish the
relationship of the Federal government
and Tribes in developing plans to attain
the NAAQS, and this rule does nothing
to modify that relationship. As this rule
does not have Tribal implications,
Executive Order 13175 does not apply.
G. Executive Order 13045: Protection of
Children From Environmental Health
and Safety Risks
EO 13045, ‘‘Protection of Children
from Environmental Health and Safety
Risks,’’ (62 FR 19885, April 23, 1997)
applies to any rule that (1) Is
determined to be ‘‘economically
significant’’ as defined under Executive
Order 12866, and (2) concerns an
environmental health or safety risk that
EPA has reason to believe may have
disproportionate effect on children. If
the regulatory action meets both criteria,
the Agency must evaluate the
environmental health or safety effects of
the planned rule on children, and
explain why the planned regulation is
preferable to other potentially effective
and reasonably feasible alternatives
considered by the Agency. This final
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rule is subject to EO 13045 because it is
economically significant as defined in
EO 12866, and we believe that the
environmental health risk addressed by
this action may have a disproportionate
effect on children. This rule implements
a previously promulgated health-based
Federal standard—the PM
2.5
NAAQS
56
.
The NAAQS constitute uniform,
national standards for PM pollution;
these standards are designed to protect
public health with an adequate margin
of safety, as required by CAA section
109. However, the protection offered by
these standards may be especially
important for children because children,
along with other sensitive population
subgroups such as the elderly and
people with existing heart or lung
disease, are potentially susceptible to
health effects resulting from PM
exposure. Because children are
considered a potentially susceptible
population, we have carefully evaluated
the environmental health effects of
exposure to PM pollution among
children. These effects and the size of
the population affected are summarized
in section 9.2.4 of the Criteria Document
and section 3.5 of the Staff Paper.
H. Executive Order 13211: Actions That
Significantly Affect Energy Supply,
Distribution, or Use
This final rule is not a ‘‘significant
energy action’’ as defined in Executive
Order 13211, ‘‘Actions That
Significantly Affect Energy Supply,
Distribution, or Use,’’ (66 FR 28355,
May 22, 2001) because it is not likely to
have a significant adverse effect on the
supply, distribution, or use of energy.
This rule is not a ‘‘significant energy
action,’’ because it does not establish
requirements that directly affect the
general public and the public and
private sectors, but, rather, interprets
the statutory requirements that apply to
States in preparing their SIPs. The SIPs
themselves will likely establish
requirements that directly affect the
general public, and the public and
private sectors.
I. National Technology Transfer
Advancement Act
Section 12(d) of the National
Technology Transfer Advancement Act
of 1995 (‘‘NTTAA’’), Public Law No.
104–113, section 12(d) (15 U.S.C. 272
note) directs EPA to use voluntary
consensus standards (VCS) in its
regulatory activities unless to do so
would be inconsistent with applicable
law or otherwise impractical. Voluntary
56
See
62 FR 38652–38760, National Ambient Air
Quality Standards for Particulate Matter, Final Rule;
also 40 CFR part 50.
consensus standards are technical
standards (e.g., materials specifications,
test methods, sampling procedures, and
business practices) that are developed or
adopted by VCS bodies. The NTTAA
directs EPA to provide Congress,
through OMB, explanations when the
Agency decides not to use available and
applicable VCS.
This final rulemaking does not
involve technical standards. Therefore,
EPA is not considering the use of any
VCS. The EPA will encourage the States
and Tribes to consider the use of such
standards, where appropriate, in the
development of their implementation
plans.
J. Executive Order 12898: Federal
Actions To Address Environmental
Justice in Minority Populations and
Low-Income Populations
EO 12898 (59 FR 7629 (Feb. 16, 1994)
establishes Federal executive policy on
environmental justice. Its main
provision directs Federal agencies, to
the greatest extent practicable and
permitted by law, to make
environmental justice part of their
mission by identifying and addressing,
as appropriate, disproportionately high
and adverse human health or
environmental effects of their programs,
policies and activities on minority
populations and low-income
populations in the United States.
The EPA has determined that the final
rule should not have disproportionately
high and adverse human health or
environmental effects on minority or
low-income populations because it
increases the level of environmental
protection for all affected populations
without having any disproportionately
high and adverse human health or
environmental effects on any
population, including any minority or
low-income population. The health and
environmental risks associated with fine
particles were considered in the
establishment of the PM
2.5
NAAQS. The
level is designed to be protective with
an adequate margin of safety. This final
rule provides a framework for
improving environmental quality and
reducing health risks for areas that may
be designated nonattainment.
K. Congressional Review Act
The Congressional Review Act, 5
U.S.C. 801 et seq., as added by the Small
Business Regulatory Enforcement
Fairness Act of 1996, generally provides
that before a rule may take effect, the
agency promulgating the rule must
submit a rule report, which includes a
copy of the rule, to each House of the
Congress and to the Comptroller General
of the United States. The EPA will
submit a report containing the rule and
other required information to the U.S.
Senate, the U.S. House of
Representatives, and the Comptroller
General of the United States prior to
publication of the rule in the
Federal
Register
. A Major rule cannot take effect
until 60 days after it is published in the
Federal Register
. This action is a ‘‘major
rule’’ as defined by 5 U.S.C. 804(2). This
rule will be effective June 25, 2007.
L. Petitions for Judicial Review
Under section 307(b)(1) of the Act,
petitions for judicial review of this
action must be filed in the United States
Court of Appeals for the District of
Columbia Circuit by June 25, 2007.
Filing a petition for reconsideration by
the Administrator of this final rule does
not affect the finality of this rule for the
purposes of judicial review nor does it
extend the time within which a petition
for judicial review may be filed, and
shall not postpone the effectiveness of
such rule or action. This action may not
be challenged later in proceedings to
enforce its requirements. See Act
section 307(b)(2).
M. Judicial Review
Under sections 307(d)(1)(E) and
307(d)(1)(V) of the CAA, the
Administrator determines that this
action is subject to the provisions of
section 307(d). Section 307(d)(1)(V)
provides that the provisions of section
307(d) apply to ‘‘such other actions as
the Administrator may determine.’’
While the Administrator did not make
this determination earlier, the
Administrator believes that all of the
procedural requirements, e.g.,
docketing, hearing and comment
periods, of section 307(d) have been
complied with during the course of this
rulemaking.
IV. Statutory Authority
The statutory authority for this action
is provided by 42 U.S.C. 7401, 7408,
7410, 7501–7509a, and 7601(a)(1). This
notice is also subject to 307(d) of the
CAA (42 U.S.C. 7407(d)).
List of Subjects in 40 CFR Part 51
Administrative practice and
procedure, Air pollution control,
Intergovernmental relations, Nitrogen
dioxide, Ozone, Particulate matter,
Sulfur oxides, Transportation, Volatile
organic compound.
Dated: March 29, 2007.
Stephen L. Johnson,
Administrator.
For the reasons set out in the
preamble, title 40, chapter I of the Code
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of Federal Regulations is amended as
follows:
1. The authority citation for part 51
continues to read as follows:
Authority:
23 U.S.C. 101; 42 U.S.C. 7401–
7671q.
2. A new Subpart Z is added to read
as follows:
Subpart Z—Provisions for
Implementation of PM
2.5
National
Ambient Air Quality Standards
Sec.
51.1000 Definitions.
51.1001 Applicability of part 51.
51.1002 Submittal of State implementation
plan.
51.1003 [Reserved]
51.1004 Attainment dates.
51.1005 One-year extensions of the
attainment date.
51.1006 Redesignation to nonattainment
following initial designations for the
PM
2.5
NAAQS.
51.1007 Attainment demonstration and
modeling requirements.
51.1008 Emission inventory requirements
for the PM
2.5
NAAQS.
51.1009 Reasonable further progress (RFP)
requirements.
51.1010 Requirements for reasonably
available control technology (RACT) and
reasonably available control measures
(RACM).
51.1011 Requirements for mid-course
review.
51.1012. Requirements for contingency
measures.
§ 51.1000 Definitions.
The following definitions apply for
purposes of this subpart. Any term not
defined herein shall have the meaning
as defined in 40 CFR 51.100.
Act
means the Clean Air Act as
codified at 42 U.S.C. 7401–7671q.
(2003).
Attainment date
means the date by
which an area, under an approved State
implementation plan, is required to
attain the PM
2.5
NAAQS (based on the
average of three consecutive years of
ambient air quality data).
Baseline year inventory
for the RFP
plan is the emissions inventory for the
year also used as the base year for the
attainment demonstration.
Benchmark RFP plan
means the
reasonable further progress plan that
requires generally linear emission
reductions in pollutants from the
baseline emissions year through the
milestone inventory year.
Date of designation
means the
effective date of the PM
2.5
area
designation as promulgated by the
Administrator.
Direct PM
2.5
emissions
means solid
particles emitted directly from an air
emissions source or activity, or gaseous
emissions or liquid droplets from an air
emissions source or activity which
condense to form particulate matter at
ambient temperatures. Direct PM
2.5
emissions include elemental carbon,
directly emitted organic carbon, directly
emitted sulfate, directly emitted nitrate,
and other inorganic particles (including
but not limited to crustal material,
metals, and sea salt).
Existing control measure
means any
Federally enforceable national, State, or
local control measure that has been
approved in the SIP and that results in
reductions in emissions of PM
2.5
or
PM
2.5
precursors in a nonattainment
area.
Full implementation inventory
is the
projected RFP emission inventory for
the year preceding the attainment date,
representing a level of emissions that
demonstrates attainment.
Milestone year inventory
is the
projected RFP emission inventory for
the applicable RFP milestone year (
i.e.
2009 and, where applicable, 2012).
PM
2.5
NAAQS
means the particulate
matter national ambient air quality
standards (annual and 24-hour) codified
at 40 CFR 50.7.
PM
2.5
design value
for a
nonattainment area is the highest of the
three-year average concentrations
calculated for the monitors in the area,
in accordance with 40 CFR part 50,
appendix N.
PM
2.5
attainment plan precursor
means S0
2
and those other PM
2.5
precursors emitted by sources in the
State which the State must evaluate for
emission reduction measures to be
included in its PM
2.5
nonattainment area
or maintenance area plan.
PM
2.5
precursor
means those air
pollutants other than PM
2.5
direct
emissions that contribute to the
formation of PM
2.5
. PM
2.5
precursors
include S0
2
, NO
X
, volatile organic
compounds, and ammonia.
Reasonable further progress (RFP)
means the incremental emissions
reductions toward attainment required
under sections 172(c)(2) and 171(1).
Subpart 1
means the general
attainment plan requirements found in
subpart 1 of part D of title I of the Act.
§ 51.1001 Applicability of part 51.
The provisions in subparts A through
X of this part apply to areas for purposes
of the PM
2.5
NAAQS to the extent they
are not inconsistent with the provisions
of this subpart.
§ 51.1002 Submittal of State
implementation plan.
(a) For any area designated by EPA as
nonattainment for the PM
2.5
NAAQS,
the State must submit a State
implementation plan satisfying the
requirements of section 172 of the Act
and this subpart to EPA by the date
prescribed by EPA which will be no
later than 3 years from the date of
designation.
(b) The State must submit a plan
consistent with the requirements of
section 110(a)(2) of the Act unless the
State already has fulfilled this obligation
for the purposes of implementing the
PM
2.5
NAAQS.
(c)
Pollutants contributing to fine
particle concentrations.
The State
implementation plan must identify and
evaluate sources of PM
2.5
direct
emissions and PM
2.5
attainment plan
precursors in accordance with
§§ 51.1009 and 51.1010. After January 1,
2011, for purposes of establishing
emissions limits under 51.1009 and
51.1010, States must establish such
limits taking into consideration the
condensable fraction of direct PM
2.5
emissions. Prior to this date, States are
not prohibited from establishing source
emission limits that include the
condensable fraction of direct PM
2.5
.
(1) The State must address sulfur
dioxide as a PM
2.5
attainment plan
precursor and evaluate sources of SO
2
emissions in the State for control
measures.
(2) The State must address NO
X
as a
PM
2.5
attainment plan precursor and
evaluate sources of NO
X
emissions in
the State for control measures, unless
the State and EPA provide an
appropriate technical demonstration for
a specific area showing that NO
X
emissions from sources in the State do
not significantly contribute to PM
2.5
concentrations in the nonattainment
area.
(3) The State is not required to
address VOC as a PM
2.5
attainment plan
precursor and evaluate sources of VOC
emissions in the State for control
measures, unless:
(i) the State provides an appropriate
technical demonstration for a specific
area showing that VOC emissions from
sources in the State significantly
contribute to PM
2.5
concentrations in the
nonattainment area, and such
demonstration is approved by EPA; or
(ii) The EPA provides such a technical
demonstration.
(4) The State is not required to
address ammonia as a PM
2.5
attainment
plan precursor and evaluate sources of
ammonia emissions from sources in the
State for control measures, unless:
(i) The State provides an appropriate
technical demonstration for a specific
area showing that ammonia emissions
from sources in the State significantly
contribute to PM
2.5
concentrations in the
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nonattainment area, and such
demonstration is approved by EPA; or
(ii) The EPA provides such a technical
demonstration.
(5) The State must submit a
demonstration to reverse any
presumption in this rule for a PM
2.5
precursor with respect to a particular
nonattainment area, if the
administrative record related to
development of its SIP shows that the
presumption is not technically justified
for that area.
§ 51.1003 [Reserved]
§ 51.1004 Attainment dates.
(a) Consistent with section
172(a)(2)(A) of the Act, the attainment
date for an area designated
nonattainment for the PM
2.5
NAAQS
will be the date by which attainment
can be achieved as expeditiously as
practicable, but no more than five years
from the date of designation. The
Administrator may extend the
attainment date to the extent the
Administrator determines appropriate,
for a period no greater than 10 years
from the date of designation,
considering the severity of
nonattainment and the availability and
feasibility of pollution control measures.
(b) In the SIP submittal for each of its
nonattainment areas, the State must
submit an attainment demonstration
justifying its proposed attainment date.
For each nonattainment area, the
Administrator will approve an
attainment date at the same time the
Administrator approves the attainment
demonstration for the area, consistent
with the attainment date timing
provision of section 172(a)(2)(A) and
paragraph (a) of this section.
(c) Upon a determination by EPA that
an area designated nonattainment for
the PM
2.5
NAAQS has attained the
standard, the requirements for such area
to submit attainment demonstrations
and associated reasonably available
control measures, reasonable further
progress plans, contingency measures,
and other planning SIPs related to
attainment of the PM
2.5
NAAQS shall be
suspended until such time as: the area
is redesignated to attainment, at which
time the requirements no longer apply;
or EPA determines that the area has
violated the PM
2.5
NAAQS, at which
time the area is again required to submit
such plans.
§ 51.1005 One-year extensions of the
attainment date.
(a) Pursuant to section 172(a)(2)(C)(ii)
of the Act, a State with an area that fails
to attain the PM
2.5
NAAQS by its
attainment date may apply for an initial
1-year attainment date extension if the
State has complied with all
requirements and commitments
pertaining to the area in the applicable
implementation plan, and:
(1) For an area that violates the annual
PM
2.5
NAAQS as of its attainment date,
the annual average concentration for the
most recent year at each monitor is 15.0
µ
g/m
3
or less (calculated according to
the data analysis requirements in 40
CFR part 50, appendix N).
(2) For an area that violates the 24-
hour PM
2.5
NAAQS as of its attainment
date, the 98th percentile concentration
for the most recent year at each monitor
is 65
µ
g/m
3
or less (calculated according
to the data analysis requirements in 40
CFR part 50, appendix N).
(b) An area that fails to attain the
PM
2.5
NAAQS after receiving a 1-year
attainment date extension may apply for
a second 1-year attainment date
extension pursuant to section
172(a)(2)(C)(ii) if the State has complied
with all requirements and commitments
pertaining to the area in the applicable
implementation plan, and:
(1) For an area that violates the annual
PM
2.5
NAAQS as of its attainment date,
the two-year average of annual average
concentrations at each monitor, based
on the first extension year and the
previous year, is 15.0
µ
g/m
3
or less
(calculated according to the data
analysis requirements in 40 CFR part 50,
appendix N).
(2) For an area that violates the 24-
hour PM
2.5
NAAQS as of its attainment
date, the two-year average of annual
98th percentile concentrations at each
monitor, based on the first extension
year and the previous year, is 65
µ
g/m
3
or less (calculated according to the data
analysis requirements in 40 CFR part 50,
appendix N).
§ 51.1006 Redesignation to nonattainment
following initial designations for the PM
2.5
NAAQS.
Any area that is initially designated
‘‘attainment/unclassifiable’’ for the
PM
2.5
NAAQS may be subsequently
redesignated to nonattainment if
ambient air quality data in future years
indicate that such a redesignation is
appropriate. For any such area that is
redesignated to nonattainment for the
PM
2.5
NAAQS, any absolute, fixed date
that is applicable in connection with the
requirements of this part is extended by
a period of time equal to the length of
time between the effective date of the
initial designation for the PM
2.5
NAAQS
and the effective date of redesignation,
except as otherwise provided in this
subpart.
§ 51.1007 Attainment demonstration and
modeling requirements.
(a) For any area designated as
nonattainment for the PM
2.5
NAAQS,
the State must submit an attainment
demonstration showing that the area
will attain the annual and 24-hour
standards as expeditiously as
practicable. The demonstration must
meet the requirements of § 51.112 and
Appendix W of this part and must
include inventory data, modeling
results, and emission reduction analyses
on which the State has based its
projected attainment date. The
attainment date justified by the
demonstration must be consistent with
the requirements of § 51.1004(a). The
modeled strategies must be consistent
with requirements in § 51.1009 for RFP
and in § 51.1010 for RACT and RACM.
The attainment demonstration and
supporting air quality modeling should
be consistent with EPA’s PM
2.5
modeling guidance.
(b)
Required time frame for obtaining
emissions reductions.
For each
nonattainment area, the State
implementation plan must provide for
implementation of all control measures
needed for attainment as expeditiously
as practicable, but no later than the
beginning of the year prior to the
attainment date. Consistent with section
172(c)(1) of the Act, the plan must
provide for implementation of all RACM
and RACT as expeditiously as
practicable. The plan also must include
RFP milestones in accordance with
§ 51.1009, and control measures needed
to meet these milestones, as necessary.
§ 51.1008 Emission inventory
requirements for the PM
2.5
NAAQS.
(a) For purposes of meeting the
emission inventory requirements of
section 172(c)(3) of the Act for
nonattainment areas, the State shall, no
later than three years after designation:
(1) Submit to EPA Statewide emission
inventories for direct PM
2.5
emissions
and emissions of PM
2.5
precursors. For
purposes of defining the data elements
for these inventories, the PM
2.5
and
PM
2.5
precursor-relevant data element
requirements under subpart A of this
part shall apply.
(2) Submit any additional emission
inventory information needed to
support an attainment demonstration
and RFP plan ensuring expeditious
attainment of the annual and 24-hour
PM
2.5
standards.
(b) For inventories required for
submission under paragraph (a) of this
section, a baseline emission inventory is
required for the attainment
demonstration required under § 51.1007
and for meeting RFP requirements
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under § 51.1009. As determined on the
date of designation, the base year for
this inventory shall be the most recent
calendar year for which a complete
inventory was required to be submitted
to EPA pursuant to subpart A of this
part. The baseline emission inventory
for calendar year 2002 or other suitable
year shall be used for attainment
planning and RFP plans for areas
initially designated nonattainment for
the PM
2.5
NAAQS in 2004–2005.
§ 51.1009 Reasonable further progress
(RFP) requirements.
(a) Consistent with section 172(c)(2)
of the Act, State implementation plans
for areas designated nonattainment for
the PM
2.5
NAAQS must demonstrate
reasonable further progress as provided
in § 51.1009(b) through (h).
(b) If the State submits to EPA an
attainment demonstration and State
implementation plan for an area which
demonstrates that it will attain the PM
NAAQS within five years of the date of
designation, the State is not required to
submit a separate RFP plan. Compliance
with the emission reduction measures
in the attainment demonstration and
State implementation plan will meet the
requirements for achieving reasonable
further progress for the area.
(c) For any area for which the State
submits to EPA an approvable
attainment demonstration and State
implementation plan that demonstrates
the area needs an attainment date of
more than five years from the date of
designation, the State also must submit
an RFP plan. The RFP plan must
describe the control measures that
provide for meeting the reasonable
further progress milestones for the area,
the timing of implementation of those
measures, and the expected reductions
in emissions of direct PM
2.5
and PM
2.5
attainment plan precursors. The RFP
plan is due to EPA within three years of
the date of designation.
(1) For any State that submits to EPA
an approvable attainment demonstration
and State implementation plan
justifying an attainment date of more
than five and less than nine years from
the date of designation, the RFP plan
must include 2009 emissions milestones
for direct PM
2.5
and PM
2.5
attainment
plan precursors demonstrating that
reasonable further progress will be
achieved for the 2009 emissions year.
(2) For any area that submits to EPA
an approvable attainment demonstration
and State implementation plan
justifying an attainment date of nine or
ten years from the date of designation,
the RFP plan must include 2009 and
2012 emissions milestones for direct
PM
2.5
and PM
2.5
attainment plan
precursors demonstrating that
reasonable further progress will be
achieved for the 2009 and 2012
emissions years.
(d) The RFP plan must demonstrate
that in each applicable milestone year,
emissions will be at a level consistent
with generally linear progress in
reducing emissions between the base
year and the attainment year.
(e) For a multi-State nonattainment
area, the RFP plans for each State
represented in the nonattainment area
must demonstrate RFP on the basis of
common multi-State inventories. The
States within which the area is located
must provide a coordinated RFP plan.
Each State in a multi-State
nonattainment area must ensure that the
sources within its boundaries comply
with enforceable emission levels and
other requirements that in combination
with the reductions planned in other
state(s) will provide for attainment as
expeditiously as practicable and
demonstrate reasonable further progress.
(f) In the benchmark RFP plan, the
State must identify direct PM
2.5
emissions and PM
2.5
attainment plan
precursors regulated under the PM
2.5
attainment plan and specify target
emission reduction levels to be achieved
during the milestone years. In
developing the benchmark RFP plan,
the State must develop emission
inventory information for the
geographic area included in the plan
and conduct the following calculations:
(1) For direct PM
2.5
emissions and
each PM
2.5
attainment plan precursor
addressed in the attainment strategy, the
full implementation reduction is
calculated by subtracting the full
implementation inventory from the
baseline year inventory.
(2) The ‘‘milestone date fraction’’ is
the ratio of the number of years from the
baseline year to the milestone inventory
year divided by the number of years
from the baseline year to the full
implementation year.
(3) For direct PM
2.5
emissions and
each PM
2.5
attainment plan precursor
addressed in the attainment strategy, a
benchmark emission reduction is
calculated by multiplying the full
implementation reduction by the
milestone date fraction.
(4) The benchmark emission level in
the milestone year is calculated for
direct PM
2.5
emissions and each PM
2.5
attainment plan precursor by
subtracting the benchmark emission
reduction from the baseline year
emission level. The benchmark RFP
plan is defined as a plan that achieves
benchmark emission levels for direct
PM
2.5
emissions and each PM
2.5
attainment plan precursor addressed in
the attainment strategy for the area.
(5) In comparing inventories between
baseline and future years for direct
PM
2.5
emissions and each PM
2.5
attainment plan precursor, the
inventories must be derived from the
same geographic area. The plan must
include emissions estimates for all types
of emitting sources and activities in the
geographic area from which the
emission inventories for direct PM
2.5
emissions and each PM
2.5
attainment
plan precursor addressed in the plan are
derived.
(6) For purposes of establishing motor
vehicle emissions budgets for
transportation conformity purposes (as
required in 40 CFR part 93) for a PM
2.5
nonattainment area, the State shall
include in its RFP submittal an
inventory of on-road mobile source
emissions in the nonattainment area.
(g) The RFP plan due three years after
designation must demonstrate that
emissions for the milestone year are
either:
(1) At levels that are roughly
equivalent to the benchmark emission
levels for direct PM
2.5
emissions and
each PM
2.5
attainment plan precursor to
be addressed in the plan; or
(2) At levels included in an
alternative scenario that is projected to
result in a generally equivalent
improvement in air quality by the
milestone year as would be achieved
under the benchmark RFP plan.
(h) The equivalence of an alternative
scenario to the corresponding
benchmark plan must be determined by
comparing the expected air quality
changes of the two scenarios at the
design value monitor location. This
comparison must use the information
developed for the attainment plan to
assess the relationship between
emissions reductions of the direct PM
2.5
emissions and each PM
2.5
attainment
plan precursor addressed in the
attainment strategy and the ambient air
quality improvement for the associated
ambient species.
§ 51.1010 Requirements for reasonably
available control technology (RACT) and
reasonably available control measures
(RACM).
(a) For each PM
2.5
nonattainment area,
the State shall submit with the
attainment demonstration a SIP revision
demonstrating that it has adopted all
reasonably available control measures
(including RACT for stationary sources)
necessary to demonstrate attainment as
expeditiously as practicable and to meet
any RFP requirements. The SIP revision
shall contain the list of the potential
measures considered by the State, and
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information and analysis sufficient to
support the State’s judgment that it has
adopted all RACM, including RACT.
(b) In determining whether a
particular emission reduction measure
or set of measures must be adopted as
RACM under section 172(c)(1) of the
Act, the State must consider the
cumulative impact of implementing the
available measures. Potential measures
that are reasonably available
considering technical and economic
feasibility must be adopted as RACM if,
considered collectively, they would
advance the attainment date by one year
or more.
§ 51.1011 Requirements for mid-course
review.
(a) Any State that submits to EPA an
approvable attainment plan for a PM
2.5
nonattainment area justifying an
attainment date of nine or ten years
from the date of designation also must
submit to EPA a mid-course review six
years from the date of designation.
(b) The mid-course review for an area
must include:
(1) A review of emissions reductions
and progress made in implementing
control measures to reduce emissions of
direct PM
2.5
and PM
2.5
attainment plan
precursors contributing to PM
2.5
concentrations in the area;
(2) An analysis of changes in ambient
air quality data for the area;
(3) Revised air quality modeling
analysis to demonstrate attainment;
(4) Any new or revised control
measures adopted by the State, as
necessary to ensure attainment by the
attainment date in the approved SIP of
the nonattainment area.
§ 51.1012 Requirement for contingency
measures.
Consistent with section 172(c)(9) of
the Act, the State must submit in each
attainment plan specific contingency
measures to be undertaken if the area
fails to make reasonable further
progress, or fails to attain the PM
2.5
NAAQS by its attainment date. The
contingency measures must take effect
without significant further action by the
State or EPA.
[FR Doc. E7–6347 Filed 4–24–07; 8:45 am]
BILLING CODE 6560–50–P
Electronic Filing - Received, Clerk's Office, December 20, 2007

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