ILLINOIS POLLUTION CONTROL BOARD
July
10,
1975
IN THE MATTER OF
)
R72-7
PROPOSED AIR QUALITY STANDARDS
)
OPINION OF THE BOARD
(by Mr. Dumelle):
This Opinion supports the Air Quality Standards for
particulates, sulfur oxides, carbon monoxide,
nitrogen
dioxide, non—methane hydrocarbons, and photochemical oxidants
adopted by the Board May
3,
1973 and July
10,
1975.
Th~
standards were adooted following a review of the record in
this proceeding wüch
includes testimony at two public
hearings,
exhibits submitted at the hearings, and written
comments submitted to the Board.
The record also
contains portions of the record in another proceeding,
R74-2, concerning health effects
of sulfur dioxide,
ordered incorporated into this proceeding by Board
Order on February
14,
1975.
The Proposed Air Quality Standards, drafted by the
Board and published
in Board Newsletter
#47 (Exhibit 1),
consisted of primary
(i.e.
health related)
and,
in some
cases, secondary
(i.e. welfare related)
standards for
particulates, sulEur oxides,
non-methane hydrocarbons,
carbon monoxide, nitrogen dioxide,
and photochemical oxidants.
Measurement methods for these pollutants were also proposed.
Table
I summarizes
the Proposed Air Quality Standards.
The Board acknowledges with appreciation the excellent
work of Edward H. Hohman, Administrative Assistant to the
Board, in this proceeding.
18
—
89
TABLE
I
PROPOSED AIR QUALITY STANDARDS
POLLUTANT
PROPOSED STANDARD
1.
Particulates
Primary
75 Jig/rn3 annual geometric mean
260 jig/rn3 maximum 24—hour,
not
to be exceeded
more than once per year
Secondary
60 pg/rn3 annual geometric mean
150 pg/rn3 maximum 24—hour,
not
to
be exceeded
more than once per year
2.
Suliur Oxides
(measured
a~’ sulfur dioxide)
Alternate
1
Primary
80 pg/m~ (0.03 ppm)
annual arithmetic mean
365
,pg/rn
(0.14 ppm)
maximum 24—hour,
not
to be
exceeded more than once per
year
Secondary
60 pg/rn3
(0.02 ppm)
annual arithmetic mean
260 pg/rn3
(0.09 ppm)
maximum 24—hour,
not
to be
exceeded more than once per
3
year
1300 )lg/m
(0.45 ppm)
maximum
3—hour,
not
to be
exceeded more than once per
year
Alternate
2
40 pg/rn3
(0.015 ppm) annual geometric mean based on
24—hour samples
265 pg/rn3
(0.10 ppm)
maximum 24—hour, not
to be
exceeded more than
1
of days
yearly
450
3.lg/m3
(0.17 ppm)
maximum 24—hour, not
to be
exceeded more than once per
3
year
1120 pg/rn
(0.42 ppm)
maximum 1—hour, not
to be
exceeded more than once per
year
TABLE
I
(Continued)
3.
Non—methane Hydrocarbons (measured as methane)
160 pg/rn3
(0.24 ppm) maximum 3—hour
(6
to
9 am),
not
to be exceeded more than
once per year
4.
Carbon Monoxide
10 mg/rn3
(9 ppm)
maximum 8—hour, not
to be exceeded
more
than once per year
40 mg/rn3 (35 ppm)
maximum 1—hour, not
to be exceeded
more than once ner year
5.
Nitrogen Dioxide
100
pg/rn3
(0.05
ppm) annual arithmetic mean
6.
Phorochernical Oxidants
160 pg/rn3
(0.08 ppm) maximum 1—hour, not
to be exceeded
more than once per year.
NOTES:
pg/rn3 means concentration in terms
of micrograms per cubic meter
mg/rn3 means concentration
in terms
of milligrams per cubic meter
—4—
The proposed standards and measurement methods, except
for sulfur dioxide alternate
2,
were consistent with the
Federal Ambient Air Quality Standards published on April 30,
1971
(Exhibit
2)
In making this proposal,
the Board discussed in some
detail the need ~or statewide ambient air quality standards.
The following excerpt from Exhibit
1 discusses this need.
“Air quality standards designating the maximum tolerable
levels for various air contaminants have been the
subject of several regulations adopted by the Air
Pollution Control Board
(Chapter V1 APCB Rules)
and of
further hearings
(R70-9,
R70—lO)
by the Pollution
Control Boarch
The regulations proposed
at this
time
are those promulgated by the Federal EPA, April
30,
1971
(36 Fed.
Reg.
8186—8201).
The federal government
further specified that these standards were to be
attained at the latest,
by July
3,
1975,
although
provision was made for limited extensions past this
date
(36 Fed.
Reg.
15486—15506, August
14,
1971).
As a
result, the control strategy embodied in the Illinois
Implementation Plan,
as well as the emission levels
specified in the recently promulgated stationary source
air emission regulations
(Parts
I and II of the PCB
Rules
—
Chapter
2),
were developed based on achieving
these levels of air quality.
We are expected by federal law to adopt and enforce
implementation plans
to achieve and maintain the new
federal standards throughout the State.
If we do not,
the federal agency will
--
the statute says-—,
and
there will be no federal funds to support state or
local air pollution control efforts.
Given this state
of affairs one course for us would be to adopt no air
quality standards of our own.
But
it is useful to have
a complete set of regulations at the state level, not
only
for ease of reference since these standards are
importantly related
to emission control limits, but
also because federal standards are not immutable and
because
in some instances we may wish to adopt stricter
standards.
The federal standards are what we can
tolerate
in crowded areas;
in national parks,
for
example, we might find stricter standards necessary.
On the other hand,
uniformity between state and federal
18
—
92
—5—
standards is obviously desirable unless there
is
solid
ground for disagreement, especially since we have
already devised a plan for achieving federal standards.
In light of the
above considerations, the PCB is
today
proposing adoption of the federal standards.
This
action also repeals and supersedes the air quality
standards of Chapter V of the APCB Rules and Regulations.
An alternative sulfur dioxide standard has been included
which applies the present Illinois standards for St.
Louis and Chicago to the entire State
(Alternate
-
2).”
Public hearings on the proposal were held on June
15,
1972 in Chicago and on June 16,
1972
in Granite City.
The
record from these hearings includes
68 pages of testimony
and 10 exhibits from
8 witnesses.
The record incorporated
from the R74—2 hearings consists of 358 pages of testimony
and 16 exhibits from
5 witnesses.
All of the submitted
material, including the comments submitted prior
to and subsequent
to the hearings has been reviewed by the Board in reaching the
findings of fact and conclusions of law contained in this
Opinion.
Public comments concerning the proposed regulations were
received
from 13 parties; citizens, industry, citizen groups, and
trade associations.
The bulk of the comments were
in reference to
the sulfur dioxide proposal.
The citizens and citizen groups
supported the more stringent Alternate
2 proposal while industry
supported, gener~11y,the proposed standards with Alternate
1.
There was,
in addition, some opposition to the secondary
standards for sulfur dioxide.
Other public comments were that
the oxidant standard was not too lax and that the particulate
standard may not be attainable.
The following sections contain discussions of each
individual pollutant for which an ambient air quality standard
was proposed.
It
is important to distinguish between proposed
primary standards and proposed secondary standards,
if such
distinctions are :dtade for a given pollutant.
According
to
Exhibit
2,
“National primary ambient air quality standards are
those which,
in the judgment of the Administrator
(of
the U.S. EPA),
based on the air quality criteria and
allowing an adequate margin of safety, are requisite to
protect the public health.
National secondary ambient air quality standards are
those which,
in the judgment of the Administrator,
based on the air quality criteria,
are requisite to
18
—
93
—6—
protect
the public welfare from any known or anticipated
adverse effects associated with the presence of air
pollutants
in the ambient air.”
Particu1ates
The major evidence regarding this pollutant is contained
in Exhibit
3, entitled “Air Quality Criteria for Particulate
Matter”
(AP-49)
published by the U.
S. Department of Health,
Education and Welfare.
This document discusses the effects
of atmospheric particulate matter on visibility, materials,
the climate, economics
(soiling, property values,
etc.),
vegetation;
and the toxicological and epidemiological effects
on animals, including humans.
Regarding health effects,
the toxic effects of particulates
are related to injury to the respiratory system of man.
As
discussed in Exhibit
3,
“Such injury may be permanent or temporary.
It may be
confined to the surface,
or it may extend beyond,
sometimes producing functional or other alterations.
Particulate material in the respiratory tract may
produce injury itself, or it may act in conjunction
with gases,
altering their sites or their modes of
action.
Laboratory studies of man and other animals
show clearly that the deposition,
clearance, and retention
is
a very complex process,
...
Particles cleared from
the respirat.ory tract by transfer to the lymph, blood,
or gastrointestinal tract may exert effects elsewhere.”
(Exhibit
3,
P.
182)
The epidemiological studies discussed in Exhibit
3 can
be used to quantify levels of particulates at which health
effects have been observed.
The following is a summary of
particulate levels and health effects contained
in the
Exhibit.
“Excess deaths and a considerable increase in illness
have bee9 observed in London at smoke levels above
750 pg/m
and
in New York at a smokeshade index of 5-6
cohs.
Sulfur oxides pollution levels were also high in
both cases.
These unusual short—term, massive exposures
result in immediately apparent pathological effects,
and they represent the upper limits of the observed
dose-response relationship between particulates and
adverse effects on health.
18
—
94
—7-.
Daily averages of smoke
above
300 ~ig/m3to 400
have been absociated with acute worsening of chronic
bronchitis patients
in England.
No comparable data are
available in this country.
Studies of British workmen
found that increased absences due to illness occurred
when smoke levels exceeded 200 pg/rn3.
Two recent British studies showed increases
in
selected
respiratory illness
in children to be associated with
annual mean smoke levels above 120 pg/rn3
.
Additional
health changes were associated with higher levels.
These effects may be of substantial significance in the
natural history of chronic bronchitis.
Changes beginning
in young children may culminate in bronchitis several
decades
later.
The lowest particulate levels at which health effects
appear to have occurred in this country are reported in
studies of Buffalo and Nashville.
The Buffalo study
clearly shows increased death rates from selected
causes
in males and females 50 to
69 years old at
annual geometric means of 100 ~ig/m3and over.
The
study suggests that increased mortality may have been
associated with residence in areas with 2—year geometric
means of 80 pg/rn3 to 100 pg/rn3.
The Nashville study
suggests increased death rates for selected causes at
levels above 1.1 cohs.
Sulfur oxides pollution was
also present during the periods studied.
In neither
study were the smoking habits of the decedents known.
Corroborating information is supplied from Fletcher’s
study of West London workers between the ages of
30 and
59.
The data indicate that with a decrease of smoke
pollution
(yearly mean)
from 140 pg/rn3 to
60 pg/rn3,
there was an associated decrease in mean sputum volume.
Fletcher noted that there may have been changes in the
tar composition of cigarettes during the period studied;
such a change could affect the findings.
This study
provides one of the rare opportunities to examine the
apparent improvement in health that followed an improvement
in the quality of the air.”
(Exhibit
3,
p.
183-184)
The Exhibit thus identifies particulate levels of
80 to
100 pg/rn3
(2 year geometric means)
as the lowest levels at
which health effects
(increased mortality)
have been observed
in the United States, and daily averages of 300
to 400 jig/rn3
as causing a worsening of chronic bronchitis.
The effects of particulates on public welfare are likewise
discussed
in Exhibit
3.
The effects include the following:
18
—
95
—8—
a)
At concentrations ranging from 100 )ig/m3 to
150 pg/ma for particulates, where large smoke turbidity
factors persist,
in middle and high latitudes direct
sunlight is reduced up to one-third in
surnnier and two-
thirds in winter.
b)
At concentrations of about 150 jig/rn3 for particulates,
where the predominant particle size ranges from 0.2
microns
to 1.0 microns and relative humidity is less
than
70 percent,
visibility is reduced to as low as
5
miles.
c)
At concentrations ranging from 60 jig/rn3
(annual
geometric mean),
to 180 pg/rn3 for particulates
(annual
geometric mean),
in the presence of sulfur dioxide and
moisture, corrosion of steel and zinc panels occurs at
an accelerated rate.
d)
At concentrations of approximately
70
jig/rn3 for
particulates
(annual geometric mean)
,
in the presence
of other pollutants, public awareness and/or concern
for air pollution may become evident and increase
proporti~natelyup to and above concentrations of
200 pg/rn
for particulates.
Exhibit
3 concludes that adverse effects on materials
were observed at ~n annual mean particulate concentration
exceeding 60
jig/rn
The particulate standards were discussed by several
witnesses at the hearings.
Kirkwood
(R.
49) and Sutton
(R.
62) supported the particulate levels.
Sutton testified
concerning the particulate levels in Granite City
(the
levels
for the first five months of 1972 averaged 200 pg/rn3
in one residential area)
and urged the Board for a “speedy
implementation of the State’s air quality standards.”
(R.
62—63)
Fancher, of Commonwealth Edison, provided the only
opposition to the levels,
stating that in
his opinion,
the
bases for these le~ielswas “extremely weak”.
(R.
30)
He
suggests that particulates from large scale fossil—fuel
combustion plumes have not been investigated
in terms of
toxicological research and that the evidence
(the Buffalo
study) regarding effects at the secondary standard level may
be caused by some other pollutant.
(R.
30-31)
Fancher also
provided information regarding particulate levels in Illinois
(Exhibit
1 to Fancher statement)
and concluded that isolated,
18— 96
—9—
non—metropolitan communities have particulate levels the
same as non—industrial suburbs,
and only slightly less than
metropolitan areas including parts of Chicago.
(R.
32)
He
suggests that
this
indicates high
“natural” background
levels of particulates which could not be reasonably controlled.
Our review of the record finds that the points raised
by Edison are not suøported.
The levels contained in the
criteria document and summarized earlier in this Opinion are
based on epiderniological studies from both Europe and North
America where the particulate levels certainly contained
contributions
from fossil—fuel combustion sources,
the
combustion being used for heating as well as power generation.
In addition, par-iculates both cause adverse effects and
magnify the adverse effects of other pollutants as pointed
out earlier
in this Opinion.
Regarding the Edison testimony
concerning the Buffalo studies, we note that Exhibit
3
reports
a positive correlation between total mortality
including mortality from chronic respiratory disease,
and particulate level;
and increased mortality at particulate
levels exceeding 80 ~ig/m3. (Exhibit
3,
p.
159)
Except for
the unknown smoking habits, we conclude that Fancher’s
statement concerning the Buffalo study is mere speculation.
Finally, our review of the Edison statement concerning
particulate ~eve~
in Illinois shows 1970 ~evels ranging
from 50 pg/ma
foi: Crystal Lake to 205 pg/rn
for Chicago
Heights;
and we question whether this is evidence as suggested
by Edison of similar particulate levels existing statewide.
Furthermore, Fancher estimates
a “natural” background of
45 pg/rn3
and adds on estimated contributions due to man’s
activity.
(Exhibit
3
of Fancher statement) We conclude from
this “evidence” that if all particulate emissions due to
man’s activity were completely abated,
a level of
45 pg/rn3
could be achieved.
This,
however,
is not required since the
primary and secondary standards we have adopted are
75 pg/rn3 and
60
jig/mi
respectively.
We,
therefore, have adopted the federal primary and
secondary standards for particulates
as state standards for
Illinois.
Sulfur Oxides
(Sulfur Dioxide)
The federal document,
“Air
Quality Criteria
for Sulfur
Oxides”
(AP-50), published by the U.S. Department of Health,
Education, and Welfare, was entered into the record as
Exhibit
4.
This document
contains
a discussion
of the
effects
of sulfur oxides
on materials,
vegetation,
animals
and man, and at the time of the hearings, formed the major
basis for setting
standards.
18—97
—10—
Sulfur dioxide
is a non—flammable, non—explosive,
colorless gas.
t is emitted to the atmosphere as
a result
of combustion processes.
The effects of sulfur dioxide on humans are related to
irritation of the respiratory system,
the injury can be
either temporary or permanent.
Broncho constriction, as
evidenced by increased airway resistance, has been shown to
occur
in man following
30 minute exposures to sulfur dioxide
at levels of
5
ppm.
Sensitive individuals exposed to
1 ppm
of sulfur dioxide have in some instances exhibited severe
bronchospasrns.
(Exhibit 4,
p.
155-156)
Epidemiolog~calstudies discussed in Exhibit
4 relate
to both short term-high level and long term-low level exposures.
The Exhibit concludes the following regarding the effects of
sulfur dioxide on human health
(Exhibit
4,
p.
161-162):
a)
At concentrations of about 1500 pg/rn3
(0.52 ppm)
of sulfur dioxide
(24-hour average), and suspended
particulate matter measured as a soiling index of
6
cohs or greater, increased mortality may occur.
b)
At concentrations of about 715 jig/rn3
(0.25 ppm)
of
sulfur dioxide and higher
(24-hour mean),
accompanied
by smoke at a concentration of 750 jig/rn3, increased
daily death rates may occur.
c)
At concentrations of about 500 jig/rn3
(0.19 ppm)
of
sulfur dioxide
(24-hour mean), with low particulate
levels,
increased mortality rates may occur.
d)
At concentrations ranging from 300 jig/rn3 to
500
jig/rn3
(0.11 ppm to 0.19 ppm)
of sulfur dioxide
(24-
hour mean)
,
with low particulate
levels,
increased
hospital admissions of older persons for respiratory
disease may occur;
absenteeism from work,
particularly
with older persons, may also occur.
e)
At concentrations of about
715 jig/rn3
(0.25 ppm)
of
sulfur dioxide
(24—hour mean)
,
accompanied by particulate
matter,
a sharp rise in illness rates for patients over
age
54 with severe bronchitis may occur.
f)
At concentrations of about
600 jig/rn3
(about 0.21
ppm)
of sulfur dioxide
(24-hour mean), with smoke
concentrations
of about 300 jig/rn3, patients with chronic
lung disease may experience accentuation of symptoms.
q)
At concentrations ranging from 105 jig/rn3
to
265 jig/rn3
(0.037 ppm to 0.092 ppm)
of sulfur dioxide
(annual mean),
accompanied by smoke concentrations of
18
—
98
—11—
about 185 jig/rn3, increased frequency of respiratory
symptoms and lung disease may occur.
h)
At concentrations of about
120 jiq/rn3
(0.046 ppm)
of sulfur dioxide
(annual mean), accompanied by smoke
concentrations of about 100 pg/rn3,
increased frequency
and severity of respiratory diseases
in school children
may occur.
i)
At concentrations of about
115 jig/rn3
(0.040 ppm)
of sulfur dioxide
(annual mean), accompanied by smoke
concentrations of about
160 jig/rn3,
increase
in mortality
from bronchitis and from lung cancer may occur.
This information was buttressed by Dr. Carnow of the
University of
Illinois Medical Center.
Dr. Carnow testified
regarding his epidemiological studies.
(Exhibit
9)
By
dividing the City of Chicago into different areas,he found
that at each level of 502 from 0.041 ppm to
5 ppm,
the
higher the level,
the greater the number of people
(male,
55
years old with advanced bronchitis)
reporting acute chest
disease.
(R.
7)
He also found increased instances of acute
illness
at SO
levels greater than 0.09 ppm and further
increases at ~O2 levels greater than 0.19 ppm.
(Exhibit
9)
He concludes
from these and other studies that there is no
threshold for SO2, that at every level
someone is affected
adversely.
“...you cannot compare a 30—year old population,
which is done frequently,
and examine them and compare them
with new—borns
(sic)
and people with emphysema and severe
arteriosclerosis,...we have
to define levels that are achievable
and those which will protect the maximum number of people.”
(R.
222)
Exhibit
4 also includes information relating to the
public welfare aspects of sulfur dioxide.
The following
conclusions are drawn from this information:
(Exhibit
4,
p.
162)
a)
At a concentration of 285 pg/rn3
(0.10 ppm)
of
sulfur dioxide, with
a comparable concentration of
particulate mattar and a relative humidity of
50 percent,
visibility may be reduced to about five miles.
b)
At a mean sulfur dioxide level of 345 jig/rn3
(0.12
ppm),
accompanied by high particulate levels, the
corrosion ra~efor steel panels may be increased by 50
percent.
C)
At a concentration of about
85 jig/rn3
(0.03
ppm)
of
sulfur dioxide
(annual mean), chronic plant injury and
excessive leaf drop may occur.
18
—
99
—12—
d)
After exposure to about
860 jig/rn3
(0.3 ppm)
of
sulfur dioxide for
8 hours, some species of trees and
shrubs show injury.
e)
At concentrations of about
145 pg/rn3 to 715 pg/rn3
(0.05 ppm to 0.25 ppm), sulfur dioxide may react synergistically
with either ozone
or nitrogen
dioxide
in short—term
exposures
(e.g.,
4 hours)
to produce moderate to severe
injury to sensitive plants.
Since there were two alternative proposals for SO
standards under consideration at the
hearings,
the iss~ewas
not only whether there should be a SO~,standard, but which
proposal
it should be.
Rissman states that Alternate 2,
which included
a 0.015 ppm annual standard,
should be adopted,
citing evidence of plant injury from SO2 at levels of 0.025
ppm to 0.017 ppm on a seasonal average.
(R.4)
Carnow
suggested that to protect the greatest number of people,
0.015 ppm was an achievable standard that should be adopted.
(R.
12)
Fancher testified that there was no toxicological
or epidemiological evidence to support the Alternate
2
standards.
He estimated that the additional cost to Edison’s
customers of complying with Alternate
2 would be
$400 million.
(R.
29)
He concluded that an 0.015 ppm annual average
cannot be achieved even though in 1970 the annual average
for Chicago was 0.017 ppm,
since at only
3 locations within
the city was 0.015 ppm reached.
(R.
38-39)
Kirkwood supported
the Alternate
2 standards but suggested that the 0.17 ppm
24-hour standard be decreased to 0.14 ppm, citing evidence
from Exhibit
4.
(R.
49—50)
Following th~hearings, the Board published for comment
a proposed final draft for sulfur oxides air quality standards
on May
17,
1973 in Newsletter
#65.
The proposed final draft
contained the Alternate
1 standards,
the federal standards,
for most of the state with the Alternate
2 standards
to
apply
to the Chicago and East St. Louis major metropolitan
areas.
Comments regarding the proposal were received from
many parties, primarily
in opposition to the more stringent
Chicago and East St. Louis provisions.
On September
14,
1973
(38 FR 25678)
the U.S. EPA Administrator
revoked the annual and 24—hour secondary standards for SO2,
and retained the ~-hour secondary standard of 1300 jig/rn3
(0.5 ppm),
not
to be exceeded more than once per year.
While not
a part of this record,
the Board takes official
notice of this event
in formulating its decision regarding
sulfur dioxide air quality standards.
18— 100
—13—
As mentioned previously, by Board Order on February 14,
1975 the portion of the record
in R74—2, SO2 Inquiry Hearings,
pertaining
to health affects was incorporated into the R72-7
proceedings.
Five witnesses testified at some length regarding
health effects, a summary of which follows.
Dr. Finklea of the U.S. EPA presented recent information
regarding the effects of sulfur oxides,
including sulfur
dioxide and sulfates.
He concluded the following regarding
the justification of the SO2 federal air quality
standard:
“I think the discussion of our additional information
has been toward saying that there
is less of
a safety margin
in the primary air quality standard,
and
if anything the
degree of control envisioned should be better supported so
that the direction of our information
is to say that we have
more support for the existing standard and we have less of
a
safety margin that we thought in the present ambient air
quality standard.”
(R.
74-2,
p.
80)
Mr.
Ross,
from Great Britian, stated that concentrations
of sulfur dioxide in the order of
1 to
2 ppm are practically
harmless
in the absence of particula~es, and that if SO
concentrations remain below 500 pg/rn
,
there
is no hea1~h
danger.
(R.
74—2,
p.
1783—1784)
He felt, however,
that the
primary and secondary standards for SO2 were reasonable and
adequate
(R.
74—2,
p.
1835)
Dr. Mueller,
from ERT, supported Finklea’s conclusion
that the SO2 primary and secondary standards are
at an
appropriate level to protect public health.
(R.
1858)
In
addition, he felt that secondary pollutants
from SO2,
such
as acid and particulate sulfates,
are likely to exacerbate
or increase adverse health effects.
(R.
1864)
Dr. Carnow’s testimony expanded on his presentation two
years earlier.
H~cited the National Academy of Science’s
report that current data on SO
shows no justification for
relaxing the air quality standards.
(R.
74—2,
p.
2063)
He
described an
18 month study that showed a direct correlation
between SO
levels
in Chicago and admissions
to the emergency
rooms of C~okCounty Hospital for acute respiratory illness
(H.
74-2,
p.
2066)
He also rebutted Ross’
testimony.
(R.
74—2,
p.
2069)
18—
101
—14—
Mr. Patzlaff of the Illinois Environmental Protection Agency
presented a literature survey on the health effects of
sulfur.
He concluded that there
is no basis for a relaxation
of the standards for sulfur oxides.
(H.
74-2,
p.
130)
The testimony from these recent hearings seems
to be
that the federal SO2 air quality standards, especially the
primary standards, are still adequate and are consistent
with recent data.
We find, based on the R74-2 information,
additional justification for adopting SO2 standards that are
identical
to the federal standards.
Based on the record established,
including the comments
relating to the proposed final draft,
the Board published on
February
18,
1975 in Environmental Register #98
a second
proposal with request for comments.
This proposal was identical
to the federal air quality standard and differed from the
previously published proposal
in that the stricter standards
for Chicago and East St. Louis were deleted, and the deleted
federal secondary standards were also deleted from the proposal.
One economic benefit of this proposal
is that the $400
million additional compliance cost to achieve Alternate
2
estimated by Edison
(R.
29)
is now moot.
Another
is that
the problem of modifying compliance plans on the part of all
emitters to meet the stricter Alternate
2 limits
is now
eliminated.
Comments regarding the latest proposed final draft were
received from the Illinois Manufacturers Association and
Olin Brass Company.
These comments urged the adoption of
the proposed sulfur oxides standards
as contained
in Environmental
Register #98.
It was also pointed out by the Agency that a
typographical error exists in Environmental Register
#98, in
that Rule 308(c)
should be headed Measurement Method rather
than Measurement Period.
We have corrected this error in
the final regulation.
We, therefore,
adopt today the sulfur oxide air quality
standards as published in Register #98 as corrected.
Non-methane Hydrocarbons
The primary evidence supporting the adoption of this
air quality standard
is contained in Exhibit
5, entitled “Air
Quality Criteria for Hydrocarbons”
(AP-50)
and published by
the U.S.
Departmer.t of Health, Education and Welfare.
This
exhibit contains
a description of the sources, nature, and
principles of control of atmospheric hydrocarbons, atmospheric
18
—
102
—15—
levels of hydrocarbons and their products,
the relationship
of atmospheric hydrocarbons
to photochemical air pollution
levels,
the effects
of hydrocarbons on vegetation, and a
toxicological appraisal of hydrocarbons.
The effects of atmospheric hydrocarbons on health and
welfare are summarized
in Exhibit
5
as they occur
in three
areas:
the effects of hydrocarbons directly on human health,
the effects of hydrocarbons
in forming photochemical oxidants,
and the effects
of hydrocarbons
on vegetation.
rphe first effect,
human health,
is not as significant
as the other effects.
Exhibit
5 summarizes direct health
effects as fol1o~s:
(Exhibit
5,
p.
8—3,
4)
“1.
The aliphatic and alicyclic hydrocarbons are
generally biochemically inert, though not biologically
inertA and are only reactive at concentrations of
102
to lO~ higher than those levels found
in the ambient
atmosphere.
No effects have been reported at
levels
below 500 ppm.
2.
The aromatic hydrocarbons are biochemically and
biologically active.
The vapors are more irritating
to
the mucous membranes than equivalent concentrations of
the aliphatic or alicyclic groups.
Systemic injury can
result from the inhalation of vapors of the aromatic
compounds;
no effects, however, have been reported at
levels below
25 ppm.”
The second effect,
formation of photochemical oxidants,
is the most important
in terms of an air quality standard;
since photochemical oxidants,
as will be discussed later
in
the Opinion,
cause adverse effects such as respiratory
irritation,
eye irritation, cracking of rubber and damage to
vegetation.
The conclusion that we reach regarding oxidants
is an air quality standard of 0.08 ppm as a maximum 1-hour
concentration.
It then becomes necessary to determine the
maximum atmospheric level of hydrocarbons allowed to insure
that the air quality standard for oxidants
is not exceeded.
Exhibit
5 discusses
the data relating to the tie—in between
hydrocarbons and oxidant levels, and contains the following
summary:
(Exhibit
5,
p.
5—11,
12)
“The development of
a model
to relate emission rates of
hydrocarbons
to ambient air quality and then to the
secondary products of photochemical reactions has
proved
to be
rn elusive problem.
Because of this lack
of an appropriate model,
the relationship between
hydrocarbon emissions and subsequent maximum daily
18
—
103
—16—
oxidant levels must be approached empirically.
The
empirical approach adopted
is
a comparison of 6:00 to
9:00 a.m. average hydrocarbon values with hourly maximum
oxidant values attained later in the day.
This approach
has
validity only because of the dominating influence
of the macro—meterological variables on both the concentrations
of precursors and photochemical products.
Furthermore,
this approach can yield useful information only when
a
large
number: of days are considered;
this guarantees
the inclusion
of all possible combinations of emission
rates, meteorological dilution and dispersion variables,
sunlight intensity,
and ratios of precursor emissions.
When maximum daily oxidant values
from such an unrestricted
data base are plotted as a function of the early morning
hydrocarbons, a complete range of oxidant values
——
starting near zero and ranging up to finite and limiting
values
——
is observed.
Given data
for a sufficient
number of days,
it becomes apparent that the maximum
values of attainable oxidant are a direct function of
the early morning hydrocarbon concentration.
This
upper limit of the maximum daily oxidant concentration
is
dependent on the metropolitan geographical
area only
to the extent that differences
in meteorological variables
exist between these areas.
Thus,
the data from all
citIes can be plotted on one graph when defining the
oxidant upper limit as a function of early morning
hydrocarbon.
In defining this oxidant upper limit,
all available
data relating directly measured non—methane hydrocarbon
values to maximum daily oxidant concentrations have
been used.
Direct observation of this
limit in the
vicinity of 200 pg/rn3
(0.1 ppm)
daily maximum 1-hour
average
oxidant
concentrations
shows
that
in order to
keep
the oxidant below this value,
the 6:00 to 9:00
a.m.
average non—methane hydrocarbon concentration must
be less than 200 jig/rn3
(0.3 ppm C).
This maximum
oxidant concentration potential may be expected to
occur on about
1 percent of the days.”
1t
should
be noted that the emphasis here
is on the
ma~iorit:yof the hydrocarbons
that are photochemically reactive.
f~orthis reason, methane,
a non—reactive hydrocarbon,
is not
included
in the measurements or the air quality standards.
The effect on vegetation has been investigated
since
t:he
1900’s,
and
the
particular hydrocarbon ethylene has been
shown
to be the major
hazard
at
ambient
concentrations.
The
effects
of
ethylene
are
summarized
in
Exhibit
5
as
follows:
(T~xhibit5, p.
6—7)
18
—
104
—17-
~‘Hydrocarbons were first recognized
as phytotoxic
air
pollut:ants about
the turn of the century as
a result of
complaints
of injury to greenhouse plants from illuminating
gas.
Ethylene
was shown to be the injurious component.
kenewed
interest
in
hydrocarbons,
and
ethylene
in
particular, occurred in the mid—l950’s when ethylene
was
found
to
be one
of
the
primary
pollutants
in
the
photochernical
smog
complex.
Research
on
several
unsaturated
and
sat:urated
hydrocarbons
proved
that
only
ethylene
had
adverse
effects
at
known
ambient
concentrations.
Acetylene
and
propylene
more
nearly
approach the activity
of
ethylene
than
do
other similar gases,
but
60
to
500
times
the
concentration
is
needed
for
comparable
effects.
In
the
absence
of
any
other
symptom,
the
principal
effect
of
ethylene
is
to
inhibit
growth
of
plants.
Unfortunately,
this effect does not characterize ethylene
because other pollutants
at sublethal dosages,
as well
as some disease
and environmental factors, will also
inhibit growth.
Epinasty of leaves and abscission of leaves,
flower
buds,
and flowers are somewhat more typical
of the
effects of ethylene, but the same effects may be associated
with nutritional imbalance,
disease, or early senescence.
Perhaps the most characteristic ethylene effects are
the dry sepal wilt of orchids and the closing of
carnation
flowers.
Injury to sensitive plants has been reported
at ethylene concentrations of 1.15
to
575
jig/rn3
(0.001 to
0.5
ppm)
during time periods of
8 to
24
hours
.
“
Ethylene
is
a major petrochemical product and
is
a
malor component of automobile exhausts.
There
is not,
however,
evidence available on the atmospheric concentrations
of ethylene or vegetation affected
in Illinois.
Thus we
cannot base
an air quality standard for hydrocarbons on the
effect of ethylene on vegetation.
There was no evidence presented during the hearings
opposing the hydrocarbon proposal.
Based on the record
developed
in
this
proceeding,
we
have
adopted
the
non-
methane
hydrocarbon
standard
as
proposed.
Carbon
Monoxide
The
major
ev~denco
presented
regarding
this
proposal
is
cont:~:tned
in Exhibit.
6
which
is
entitled
“Air
Quality
Criteria
for
Carhon
Monoxide”
(AP-62)
and
is
published
by
the
U.S.
Pepartmc’nt.
of
heal
th,
Education,
and
Welfare.
This
document
18— 105
-18-
discusses,
in part,
the occurrence, properties,
and fate of
atmospheric carbon monoxide, principles of formation and
control of carbon monoxide, effects on plants and microorganisms,
toxicological effects,
and an epidemiological
appraisal.
Carbon monoxide
(CO)
i_s a colorless,
odorless,
tasteless
gas.
It occurs
in the atmosphere because of the incomplete
oxidation
of carbonaceous material,
including the incomplete
combustion
of organic materials.
The major emission source
of CO, particularly
in urban areas,
is the internal combustion
engine used in vehicles; major industrial sources include
steel mills, petroleum refineries and foundries.
The effects of CO on plants and microorganisms occur
at
higher
levels
than
the effects on animals.
Detrimental
effects
on
certain
“higher
order plants” have occurred,
according
to
Exhibit
6,
at
levels
greater
than
100
ppm
after
exposures
of
1
to
3 weeks.
Nitrogen fixation by certain
bacteria
in clover roots was inhibited by
100
ppm
CO
for
an
exposure of
1 month.
(Exhibit
6,
p.
7—2)
These effects
are,
however,
not controlling in terms of establishing
an
air quality standard.
The effects of CO on humans
is discussed
in detail
in
Exhibit
6.
The following excerpts summarize the toxicological
and epidemiological effects of CO.
(Exhibit
6,
p.
10-3)
“Co
is absorbed by the lung and reacts primarily with
hernoproteins and most notably with the hemoglobin of
the
circulating
blood.
The
absorption
of
CO
is
associated
with
a reduction
in
the oxygen—carrying capacity
of
blood and in the readiness with which the blood gives
up its available oxygen to the tissues.
The affinity
of hemoglobin for CO is over 200 times that for oxygen,
indicating that carboxyhernoglobin
(COT-Tb)
is
a more
stable compound that oxyhemoglobin
(O~Hb).
About
20
percent of an absorbed dose of CO
is round outside of
the vascular system, presumably
in combination with
myoqlobin and heme—containing enzymes.
The magnitude
of
absorption
of
CO
increases
with
the
concentration,
the
duration
of
exposure, and the ventilatory rate.
With
fixed
concentrations
and
with
exposures
of
sufficient
durat:ion,
an
equilibrium
is
reached;
the
equilibrium
is
reasonably
ptedictable
from
partial—pressure
ratios
of
oxygen
to
CO.
18—106
—19—
Long-term
exposures of animals
to
sufficiently
high
CO
concentrations
can
produce
structural
changes
in
the
heart
and
brain.
It
has
not
been
shown
that
ordinary
ambient exposures will produce
this.
The lSwest exposure
producing any such changes has been 58
mg/in
(50 ppm)
continuously
for
6
weeks.
The
normal or “background”
concentration of
COHb
in
nonsmokers
is
about
0.5
percent
and
is attributed to
endogenous
sources
such
as
heme
catabolism.
The
body’s
uptake
of
exogenous
CO
increases
blood
COHb
according
to
the concentration and length of
exposure
to CO as
well
as
the
respiratory
rate
of
the
individual.”
The
results
of
the toxicological appraisal according to
Exhibit
6
are
the
following
summary
statements.
(Exhibit
6,
p.
10—4)
“
(1)
no
human
health
effects
have
been
demonstrated
for
COHb
levels
below
1
percent,
since
endogenous
CO
production
makes this
a physiological range;
(2) the following
effects on the central nervous system occur
above
2
percent COHb:
(a)
at about
2.5 percent COHh
in nonsmokers
(from exposure to
58 mg/m-~for
90 minutes),
an impairment
in time—interval discrimination has been documented,
(b)
at aboi~t3 percent COHh
in nonsmokers
(from exposure
to
58 mg/rn
for
50 minutes)
,
an impairment
in visual
acuity and relative brightness threshold has been
observed,
(c)
at about
5 percent COHb there
is an
impairment in performance of certain other psychomotor
tests;
(3)
cardiovascular changes have been shown
to
occur at exposure sufficient
to produce over
5 percent
COHb;
they include increased cardiac output,
increased
arterial—venous
oxygen difference, increased coronary
blood flow
in patients without coronary disease, decreased
coronary sinus blood P02
in patients with coronary
heart disease, impaired oxidative metabolism of the
myocardium, and other
related effects; these changes
have been demonstrated to produce an exceptional burden
on some patlents with heart disease;
and
(4)
adaptation
to CO may occur through increasing blood volume,
among
other
mechanisms.”
Proceeding
or.e
step
further,
i.e.
relating
exposures
to
CO
with
effects
on
humans,
the
following
results
are
shown.
(Exhibit
6,
p.
10—5,
6)
18—
107
—20—
1.
Experimental exposure of nonsmokers to
a concentration
of
35
mg/rn3
(30 ppm)
for
8
to
12 hours has shown that
an
equl libriurn
value
of
5
percent
COHh
is
approached
in
this
time;
about
80
percent
of
this
equilibrium
value,
I .c.
,
4
percent
COHb,
is
present
after
only
4
hours
of
exposure.
These
experimental
data
verify
formulas
used
for
estimating
the
equilibrium
values
of
COT-lb after
exposure
to
low
concentrations of CO.
These formulas
indicate
that
continuous exposure of nonsmoking sedentary
individuals
to
23
mg/rn3
(20
ppm)
will
result
in
a
blood
COHb level of about
3.7
percent,
and
an
exposure
to
12
mg/rn3
(10 ppm) will result
in
a blood level of about
2
percent.
2.
Experimental
exposure
of
nonsmokers
to
58
mg/rn3
(50
ppm)
for
90
minutes
has
been
associated
with
impairment
in
time-interval discrimination.
This exposure will
produce
an
increase of about
2 percent COHb in the
blood.
This
same
increase
in
blood COHb will occur
with
continuous
exposure
to
12
to
17
mg/rn3
(10
to
15
ppm)
for
8
or
more
hours.
3.
Experimental exposure to CO concentrations sufficient
to produce blood COHb levels of about
5 percent
(a
~eveJ producible by exposure to about
35 mg/rn3 for
8 or
more hours)
has provided,
in some instances,
evidence
ol
impaired performance on certain other psychomotor
test:s,
and an
impairment
in visual discrimination.
4.
Experimental exposure to CO concentrations
sufficient
to produce blood COHb levels above
5 percent
(a
level
producible by exposure to
35 mg/rn3 or more for
8 or
more hours)
has provided evidence of physiologic stress
in
patients
with
heart
disease.
Thus,
a
CO
level
of
10
to
15
ppm,
i:
it
exists
for
an
8-hour
period
or
r:lore,
will
result
in
a
COHb
level
of
2
to
2.5
percent,
which
is
associated with adverse health effects.
in
addit:ion,
a
CO
level
of
35
ppm,
if
it
exists
for
a
one
hour
period,
would result
in approximately the same
2
percent
COIlU
level
(See Exhibit
6,
p.
8—9)
.
Furthermore,
the
U.S.
I~PAAdministrator,
in promulgating
the federal air quality
st.ancLirds,
stated
that the
CO
standards
are
“intended
to
protect:
against
the occurrence
of carboxyhemoglobin
levels
ab)Ve
2
pc’ rcen t
.
“
(Exh :ib it
2
18—
108
-21—
Once again the record does not contain any opposition
to the CO levels proposed by the Board.
Additional support
for the levels was provided,
in general
terms,
by Kirkwood.
Based on the record, the Board adopted the carbon
monoxide air quality standards as proposed.
Nitrogen Dioxide
The record for nitrogen dioxide
(NO~,) is contained
mainly in Exhibit
7,
“Air Quality Criterta for Nitrogen
Oxides”
(AP-84), published by the U.S.
EPA.
This document
discusses the properties and occurrences of nitrqgen oxides
(NOr), nitrogen dioxide
(NO
)
is of concern here,
and the
effects of NOx
on materiai, vegetation,
and health.
Nitric oxide
(NO)
and nitrogen dioxide
(NO2)
are the
two oxides of nitrogen considered to be significant pollutants
in the atmosphere.
They are emitted primarily from combustion
processes, with the bulk of the NO~emissions being in the
form of NO.
The NO is then converted,
in the atmosphere,
by
photochemical reactions and oxidation with oxygen to NO2.
Typical peak atmospheric levels of these oxides of nitrogen
are 0.05 ppm for NO2 and 0.10 ppm for NO.
(Exhibit
7,
p.
6-
10 to 6—13)
The effects of NO~on materials are most severe on
textile dyes and additives.
Exhibit
7 reports that fading
of sensitive disperse dyes used on cellulose acetate fibers
has been attributed to NO2 levels below 100 ppm, and that
other effects on dyes and textile fibers has been attributed
to NOR.
(Exhibit
7,
p. 113)
The effects of NO2 on vegetation have not been demonstrated
at atmospheric concentrations according to Exhibit
7.
Concentrations of 0.5 ppm to 25 ppm have resulted in visible
injury such as leaf drop and chiorosis.
There is also
evidence that exposure for
8 months to NO
concentrations of
0.25 ppm or less caused leaf drop and red~cedyield in naval
oranges.
(Exhibii~ 7,
p.
11-4)
While NO is not considered a threat to human health
at ambient concentrations, studies have shown definite human
health effects for exposures to NO
at ambient levels.
The
primary toxic effect of NO2 is on ~he lungs.
The following
summary of direct health effects
is taken from Exhibit
7.
(1)
Short-Term Exposure.
Limited studies show that
exposure to NO2 for less than 24 hours continuously can
have several concentration-dependent effects.
18—
109
—22—
1.
The olfactory threshold value of NO2
is about
225 ug/m3
(0.12 ppm).
2.
Exposure to 9.4 mg/rn3
(5
ppm)
for
10
minutes
has produced transient increase in airway resistance.
3.
Occupational exposure to 162.2
mg/rn3
(90 ppm)
for 30 minutes has produced pulmonary edema
18
hours later, accompanied by an observed vital
capacity that was 50 percent
of
the value predicted
for the normal pulmonary function.
(2)
Long—Term
Exposure.
An increased incidence of
acute respiratory disease was observed in family groups
when the mean range of 24-hour NO
concentrations,
measured over a 6—month period, w~sbetween 117 and
205 jig/rn3
(0.062 and 0.109 ppm)
and the
mean
suspended
nitrate level during the same period was 3.8 .ug/m3 or
greater.
rfhe frequency of acute bronchitis
increased among
infants and school children when the
range of mean 24-
hour NO2 concentrations, measured over a 6-month period,
was between 118 and 156 pg/rn3
(0.063 and 0.083 ppm)
and the mean suspended nitrate level during the same
period was 2.6 pg/rn3
or greater.
Exhibit
7 summarizes the nationwide implications of the
above long—term results, referred to as the Chattanoog
studies.
Yearly average NO2 concentrations exceed ~he
Chattanooga health-effect-related value of 113
jig/rn
(0.06
ppm)
in 10 percent of cities in the United States with
populations of less than 50,000,
54 percent of cities with
populations between 50,000 and 500,000 and 500,000, and
85
percent of cities with populations over 500,000.
In addition to the direct health effect, NOR, along
with
reactive hydrocarbons, are precursor compounds that
participate
in the formation of photochemical oxidants.
Specifically,
the following photolytic reaction involving
NO2,
NO2
NO+O,
frees an oxygen for the subsequent
formation of ozone
(03) and other oxidants using the reactive
hydrocarbons that are present.
One possible way, therefore,
of insuring that an oxidant air quality standard
is
not
exceeded is to limit the concentration of NOx available to
participate in the photochexnical reactions.
18—110
—23—
Exhibit
7 relates oxidant levels
to NO
(and hydrocarbon)
levels.
The relationship found
is as
follo*s:
(Exhibit
7,
p.
11—11)
“An analysis of
3 years of data collected
in three
American cities shows that on those several days
a year
when meteorological conditions are most conducive to
the formation of photochemical oxidant,
and the 6-to-~
a.m. nonmethane hydrocarbon concentration
is 200 pg/rn
(0.3 ppm C),
a 6—to
9 a.m.
NO
concentration
(measured
by the continuous Saltzman Me~hodand expressed
as NO2)
that
ranged
between
80
and
320
pg/rn3
(0.04
and
0.16
ppm)
would
be
expected
to
produce
a
1—hour
photochemical
oxidant
level
of
200
jig/rn3
(0.1
ppm)
2
to
4
hours
later.
If this same functional relationship exists at
the
lowest
levels
at
which
photochemical
oxidant
has
been observed to adversely affect human health,
the
corresponding nonmethane hydrocarbon concentration
would be approximately 130 jig/rn3
(0.2 ppm C)
and the
6-
to
9 a.m. NO~level would be as high as 214
jig/rn3
(0.11
ppm)
.“
The only objection
to the proposed NO
level was by
Edison.
Their comment was that they didn’~know how much of
the control strategy for nitrogen oxides was feasible.
(R.
43)
As with the other pollutants Kirkwood supported the
proposal
for NO2.
(R.
49)
Based
on
the
record,
the
Board
has
adopted
the
nitrogen
dioxide air quality standard as proposed.
Photochemical Oxidants
The major evidence concerning
this pollutant
is contained
in Exhibit
8, entitled “Air Quality Criteria for Photochemical
Oxidants”
(AP-63)
and published by the U.S. Department of
Health, Education,
and Welfare.
This document discusses
bhe characteristics
of oxidants,
atmospheric concentrations,
sources of ozone, measurement techniques,
effect of oxidants
on veqetation and microorganisms,
effect on materials,
and a
t:oxicological and an epidemiological
appraisal of oxidants
on animals including humans.
Photochemical oxidants are a class of chemical compounds
formed by
a series of atmospheric reactions involving nitrogen
oxides and certain organic compounds.
The energy for the
reactions
is provided by the ultraviolet component of sunlight.
The
products
of
these
reactions
are
photochemical
oxidants,
ozone
being
the
major constituent
in terms
of concentration.
18—111
—24—
other individual oxidants that have been identified
include
nitrogen
dioxide,
peroxyacyl
nitrates
(PAN),
formaldehyde,
acrolein, and organic peroxides.
The complex nature of the
reactions
is indicated by the fact that nitrogen dioxide
is
both a photochemical oxidant and a precursor compound,
due
Lo the photolytic reaction, described previously,
in the
photochemical formation process.
The control of oxidant levels
is not as straightforward
as other pollutants,
since one does not control oxidant
emissions directly,
but rather controls the precursor compounds,
nitrogen oxides and photochemically reactive organics.
The
resulting oxidant level will also depend on the incident
solar radiation intensity and the time for the chemical
reactions
to
occur
in
an
area,
parameters
not
able
to
be
controlled.
The effects
of
oxidants,
in particular ozone,
on materials
has
been
known
for some time.
Many organic polymers are
altered by ozone at
levels found
in the atmosphere.
Rubber
is extremely sensitive
to ozone, especially when under
tension.
According
to Exhibit
8,
cracking of rubber can
occur from exposure to ozone levels of 0.01 to 0.02
ppm.
This
can
be
prevented
by
the
addition
of
expensive,
and
not
totally effective anti—oxidant chemicals.
Other effects
caused by ozone exposures include fading of some dyes and
deterioration of some fabrics, although no quantitative
evidence
is available.
The effects of oxidants
on vegetation
is discussed
next.
As summarized by Exhibit
8:
(Exhibit
8,
p.
10—3)
“Injury to vegetation
is one of the earliest manifestations
of photochemical air pollution,
and sensitive plants
are useful biological
indicators of this type of pollution.
The visible symptoms of photochemical oxidant produced
injury
to plants may be classified as:
(1)
acute
injury,
identified by cell collapse with subsequent
development of necrotic patterns:
(2)
chronic
injury,
identified by necrotic patterns with or without chlorotic
or other pigmented patterns;
and,
(3)
phsyiological
(sic)
effects,
identified by growth alterations,
reduced
reduced yields,and changes
in the quality of plant products.
The
acute
symptoms
are
generally
characteristic
of
a
specific
pollutant;
though
highly
characteristic,
chronic
injury
patterns
are
not.
Ozone
injury
to
leaves
is
identified
as
a
stippling
or
flecking.
Such
injury
has
occurred experimentally in
the
most
sensitive
species
after
exposure
to
60
pg/rn3
(0.03
ppm)
ozone
for
B hours.
Injury will occur
in
shorter
time
periods
18—112
—25—
when
low levels of sulfur dioxide are present.
PAN-
produced injury is characterized by an under—surface
glazing or bronzing of the leaf.
Such injury has
occurred experimentally i~the most sensitive species
after exposure to
50 pg/ma
(0.01 ppm)
PAN for
5 hours.
Leaf injury has occurred in certain sensitive species
after
a 4-hour exposure to 100 jig/rn3
(0.05 ppm)
total
oxidant.
Ozone appears to be the most important phytotoxicant
in the photochernical complex.”
The
effect
of oxidants on humans include eye irritation,
and adverse effects on the respiratory system.
This
in
turn
may
affect
motor
performance,
and morbidity
in persons with
respiratory problems.
As summarized by Exhibit
8:
(Exhibit
8,
p.
10—9,
10—10)
a.
Ozone
(1)
Long—term exposure of human subjects.
(a)
Exposure to a concentration of up to
390
pg/rn3
(0.2
ppm)
for
3
hours
a
day,
6 days a week,
for 12 weeks,
has not produced
any apparent effects.
(b)
Exposure to a concentration of 980 pg/m3
(0.5 ppm)
for
3 hours
a day,
6 days
a week,
has caused a decrease
in the 1—second forced
expiratory volume
(FEy l.o~after
8 weeks.
(2)
Short—term exposure of human subjects.
(a)
Exposure to a concentration of
40
pg/rn3
(0.02
ppm)
was
detected
immediately
by
9
of
10
subjects.
After an average of
5 minutes
exposure,
subjects could no longer detect
ozone.
(b)
Exposure
to
a
concentration
of
590
pg/rn3
(0.3
ppm)
for
8 hours appears
to be the threshold
for nasal and throat irritation.
(c)
Exposure
to concentrations of from 1,180
to
1,960 pg/rn3
(0.6 to 1.0 ppm)
for
1 to
2 hours
may impair pulmonary function by causing
increased airway resistance, decreased carbon
monoxide diffusing capacity, decreased total
capacity,
and decreased forced expiratory
volume.
18
—
113
—26—
(d)
Exposure to concentrations of from 1,960
to
5,900 pg/rn3
(1.0 to
3.0
ppm)
for
10
to
30
minutes is intolerable
to some people.
(e)
Exposure to
a concentration of
17,600
pq/m3
(9.0
ppm)
produces severe illness.
b.
Oxidants
(1)
Long-term exposure of human subjects.
Exposure to ambient air contain~ngan oxidant
concentration of about 250 pg/m-~ (0.13 ppm)
(maximum
daily value)
has caused an increase
in the number
of asthmatic attacks in about
5 percent of
a group
of asthmatic patients.
Such a peak value would be
expected to be associated with a maximum hourly
average concentration of 100 to 120 jig/rn3
(0.05 to
0.06 ppm).
(2)
Short—term exposure of human subjects.
(a)
Exposure
to an atmosphere with peak oxidant
concentrations
of
200
jig/rn3
(0.1
ppm)
and
above has been associated with eye irritation.
Such a peak concentration would be expected
to be
associated
with
a maximum hourly average
concentration of
50 to 100 ,ug/m3
(0.025
to
0.05 ppm).
(b)
Exposure
to an atmosphere with average hourly
oxidant concentrations ranging from 60
to
590 pg/rn~ (0.03
to 0.30 ppm)
has been associated
with impairment of performance of student
athletes.
The measurement technique proposed is
specific for
ozone,
the major but not the only oxidant present
in the
atmosphere.
Therefore,
the air quality standard of 0.08 ppm
for photochemical oxidants
is really an ozone standard,
since only ozone is measured, which allows ambient levels of
total oxidants
to exceed 0.08 ppm.
No opposition
to the proposed standard was presented at
the hearings.
Upon a review of the
record, we concluded
that the air quality standard for photochemical oxidants
should be adopted
in the form proposed.
18—114
—27--
Technical Feasibility and Economic Reasonableness
The
record
does
not
contain
much
new
information
regarding
technical feasibility and economic reasonableness,
since
these issues have already been addressed in conjunction with
the R7l-23 proceeding concerning Emission Standards.
It should be understood that one does not clean up the
ambient air directly, but rather establishes limits on the
emissions of pollutants
in order
to
not
exceed
the
air
quality standards
for these pollutants.
For example,
limits
on the emissions of particulates
are designed to achieve
compliance
with
the
federal
air
quality standards for particulates.
In the prior Board proceeding, R7l—23, which concerned
emission
standards,
limits
on
the
emissions
of
particulates,
sulfur oxides, nitrogen oxides, hydrocarbons,
and carbon
monoxide were established as part of the State Implementation
Plan for achieving compliance with the Federal Air Quality
Standards.
These emission limitations were ordered by the
Board following a thorough review of the economic reasonableness
and technical
feasibility of the limits,
as discussed
in the
R7l-23 Opinion of the Board.
It follows that since the air
quality standards we adopted on May
3,
1973 and the SO2
Standard we have adopted
today are identical to the federal
standards,
upon which our emissions standards are based,
the
considerations of technical feasibility and economic reasonableness
have already been taken
into consideration in the prior proceeding.
In fact, the only new economic issue raised at the
Iiearinqs was by Edison and
it concerned the Alternate
2
sulfur oxides proposal.
We have not adopted Alternate
2 so
this issue is now moot.
Legally Enforceable Standards
Shell Oil suggested that the Board delete the portion
of proposed Rule 301 that made the air quality standards
“legally
enforceable”.
(R.
57—58)
The
problem,
as
they
see
it,
is
that
they
may
be
in an area that violates an air
quality standard and thus liable even though they are in
compliance with the emission standards.
Our response
is
that the air quality standards are the ultimate
issue.
Emission standards and implementation plans have as their
goal the achievement of certain air quality standards.
By
the adoption of standards for Illinois, we are responding to
18—
115
—28—
our mandate to provide people with a healthful environment
in Illinois.
Measurement Methods
Measurement methods for particulates, sulfur dioxide,
non-methane hydrocarbons, carbon monoxide, nitrogen dioxide,
and photochemical oxidants adopted by the Board on May
3,
1973 and July
10,
1975 are identical to the federal procedures.
This was done for the purposes of uniformity and in the absence
of opposition
at the hearings to these procedures.
Furthermore,
the Agency may approve alternate measurement methods
in order
to allow the use of equivalent procedures developed subsequent
to the federal promulgation of standards.
This Opinion constitutes the Board’s findings of fact and
conclusions of law.
I, Christan L. Moffett, Clerk of the Illinois Pollution Control
Board, hereby certify the above Opinion was adopted on the
/o’~”
day
of July,
1975 by a vote
of
.~-Q
Christan L. Moffett,
rk
Illinois Pollution C
ol Board
18—
116