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TITLE 35: ENVIRONMENTAL PROTECTION

SUBTITLE B: AIR POLLUTION

CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY

PART 291

RULES FOR THE PERFORMANCE OF AIR QUALITY IMPACT ANALYSES TO BE USED

IN SUPPORT OF PERMIT APPLICATIONS

SUBPART A: GENERAL PROVISIONS

Section

291.101

Statutory Authority

291.102

Purpose

291.103

Overview of Procedures

SUBPART B: ELEMENTS OF THE AIR QUALITY ANALYSIS

Section

291.201

Study Area and Background Concentrations

291.202

Point Source Emissions Inventory Data

291.203

County-Wide Area Source Emissions Inventory

291.204

Meteorological Data

291.205

Air Quality Data

291.206

Dispersion Modeling

291.207

Emission Projection and Allocation Techniques

SUBPART C: CONTENTS OF THE AIR QUALITY STUDY

Section

291.301

Contents of the Air Quality Study Submitted in Support of a Permit Application

for an SO

or TSP Emission Source

APPENDIX A Rule into Section Table

AUTHORITY: Implementing and authorized by Sections 4 and 39 of the Environmental

Protection Act (Ill. Rev. Stat. 1981, ch. 111 1/2, pars. 1004 and 1039).

SOURCE: Filed and effective December 30, 1977; codified at 8 Ill. Reg. 870.

SUBPART A: GENERAL PROVISIONS

Section 291.101

Statutory Authority

These rules are promulgated pursuant to authority conferred on the Illinois Environmental

Protection Agency (Agency) by Sections 4 and 39 of the Environmental Protection Act (Ill. Rev.

Stat. 1981, ch. 111 1/2, pars. 1004 and 1039) (Act).

Section 291.102

Purpose

These rules were developed by the Agency to provide guidance to sources that choose to

show compliance with Section 9(a) of the Act or Rule 102 of the Pollution Control Board

Rules and Regulations, Chapter 2: Air Pollution (codified as 35 Ill. Adm. Code 201.141),

by performing comprehensive air quality impact evaluations.

These rules were formulated in response to the remand by the Illinois Supreme Court to

the Pollution Control Board (Board) of the adoption of Rules 203(g)(1), 204(a)(1) and

204(c)(1)(A) (codified as 35 Ill. Adm. Code 212.201 through 212.205, 214.121(a) and

214.141), which established particulate and sulfur dioxide emission standards for new

and existing fuel combustion sources. Commonwealth Edison v. Pollution Control

Board, 62 Ill. 2d 494 (1976). The Court's decision, however, did not eliminate the

requirement of construction or operating permits for solid fuel emission sources; it also

did not eliminate the prohibition of air pollution contained in Section 9(a) and Rule 102

nor the prohibition of ambient air quality violations contained in Rule 102.

Thus, for any period that Rules 203(g)(1), 204(a)(1) or 204(c)(1)(A) are not effective,

construction and operating permit applications for solid fuel combustion sources will be

evaluated on the basis of comprehensive air quality impact evaluations performed by the

applicant and designed to enable the Agency to determine the status of compliance with

respect to the air quality provisions of Section 9(a) and Rule 102.

In lieu of performing comprehensive air quality impact evaluations in accordance with

these rules, the applicant may elect to show compliance with the emission limitations

contained in Rules 203(g)(1), 204(a)(1) and 204(c)(1)(A), even if those rules are not

currently effective. Compliance with these emissions limitations will usually be deemed

by the Agency to be sufficient to assure compliance with the air quality provisions of

Section 9(a) of the Act and Rule 102. Of course, for any period of time in which Rules

203(g)(1), 204(a)(1) or 204(c)(1)(A) are in effect, the permit applicant must show

compliance with these rules, without regard to comprehensive air quality analysis done

pursuant to these rules. Compliance with these rules may only be used to support permit

applications when Rules 204(g)(1), 204(a)(1) or 204(c)(1)(A) are not effective.

Section 291.103

Overview of Procedures

These procedures are designed to serve as guidelines for applicants desiring to develop

particulate and sulfur dioxide emission limitations for a subject emission source.

The procedures consist of two phases. The first phase requires an analysis of the air

quality in the vicinity of the subject source for a base year. For the base year analysis a

point and area source emissions inventory, consisting of emission rates and stack

parameters for all point sources and emission rates for county-wide area sources affecting

the study areas, are required. Base year air quality, meteorolgical data and the necessary

sub-county allocation parameters (i.e., employment, population, etc. used to allocate

county-wide area source emissions to sub-county grid squares) are required to be valid

for the time frame for which the emissions inventory is valid.

The point and area source emissions inventory data, along with air quality data and

meteorological data, should be input to an acceptable air quality dispersion model. This

simulation model should be validated and calibrated by the applicant. Procedures for and

results of this effort should be carefully documented. After calibration, the simulated air

quality in the vicinity of the subject source should be compared with the ambient air

quality standards as shown in the following table. If a violation is indicated with the

subject source operating at the proposed emission rates, the source must reduce the

emission rates so that the AAQS are not exceeded. If a violation is not indicated, the

source should proceed to Phase II.

Ambient Air Quality Standards

Pollutant

Time of

Primary

Secondary

Average

Standard

Particulate

Annual 75 ug/m3

60 ug/m(3)

Matter

Geometric

Mean

(TSP)

24 hour

260 ug/m(3) 150 ug/m(3)

Sulfur

Annual 80 ug/m(3)

None

Dioxide

Geometric

Mean

(SO(2))

24 hour

365 ug/m(3) None

3 hour None

1300 ug/m(3)

Phase II of the analysis is designed to assess the impact of the subject source on the

ambient air quality for the year 1980, as a minimum. The base year point and area source

emissions should be multiplied by appropriate growth factors developed by the applicant

for the specific study area. When determining future annual air quality, meteorological

data averaged over a minimum period of five consecutive years and model calibration

data developed for the base year analysis should be utilized. Dispersion modeling should

again be performed to determine if violations of the AAQs are indicated for the

projection year(s). If a violation is indicated, the subject source must revise its emission

rates so that the AAQS are not violated. If no violation of the AAQS are indicated by

dispersion modeling, the subject facility should submit the proper application to the

Agency for evaluation.

SUBPART B: ELEMENTS OF THE AIR QUALITY ANALYSIS

Section 291.201

Study Area and Background Concentrations

The study area shall include all territory surrounding the subject facility which

encompasses a common aggregation of sources, usually an urbanized/industrial area

bounded by areas which are now undeveloped. The analysis must consider the

following:

All point and area source emissions originating within the urbanized/industrial

area must be considered in the analysis.

Any emission source located beyond the undeveloped boundary of the

urbanized/industrial area if such source contributes one microgram per cubic

meter or more to the sulfur dioxide and/or particulate annual average; 10

micrograms per cubic meter or more to the maximum sulfur dioxide and/or

particulate 24-hour concentration; or, 50 micrograms per cubic meter or more to

the maximum 3 hour sulfur dioxide concentration within the study area.

The effect of the subject facility outside of the territory defined above when such

facility contributes the same annual and/or short-term concentrations in other

urbanized/industrial areas located outside of the study area.

The influence of topography and geography on the dispersion of air pollutants

when performing the analyses to determine the study area or impacted areas

outside the study area.

Background concentrations contained in the "clean" air entering the study area may be

considered to be 40 micrograms per cubic meter for particulates and 10 micrograms per

cubic meter for sulfur dioxide when calculating annual average concentrations. When

calculating the second highest short-term concentration for purposes of comparison to the

short-term primary standards, the critical meteorological conditions associated with such

second highest concentration must be identified. The background concentration

associated with these meteorological conditions shall be estimated using available air

quality data and information pertaining to emission sources located outside of the study

area.

Section 291.202

Point Source Emissions Inventory Data

A detailed point source emissions inventory must be used to assess the ambient air

quality. The following point sources shall be identified:

All point sources outside the subject facility and within the study area which emit

25 tons per year or more of the specified pollutant per year to the ambient air.

All point sources of the specified pollutant within the subject facility.

Data for each point source should be valid for the same period of time as the

meteorological and air quality data and should include, as a minimum:

The facility name and address.

The location of all the emission sources in the subject facility and their

relationship to each other.

The maximum hourly controlled emission rate, which is the greatest quantity of

emissions that a source is expected to produce during any one-hour of operation.

The annual average hourly controlled emission rate, which is the total controlled

emissions for a 12-month period divided by the total hours of operation for the

same period.

Stack height, stack diameter, exit gas temperature, and exit gas velocity.

The point source emissions inventory data should be obtained whenever possible from

the Division of Air Pollution Control, Illinois Environmental Protection Agency, 2200

Churchill Road, Springfield, Illinois, 62706. If the Agency does not have what it

considers to be complete data for all sources affecting the study area, the data should be

obtained from facilities in question.

Section 291.203

County-Wide Area Source Emissions Inventory

An area source emissions inventory, valid for the same time period as the point source emissions

inventory, should be used to determine the contribution to the ambient air quality of sources

other than those identified in the point source emissions inventory. A county-wide area source

emission inventory for any county within Illinois should be obtained from the Division of Air

Pollution Control, Illinois Environmental Protection Agency, 2200 Churchill Road, Springfield,

Illinois 62706. For counties outside the State of Illinois, county-wide area source emissions

inventory information from the National Emissions Data System (NEDS) may be obtained

through the Air Surveillance Branch, Region V, United States Environmental Protection Agency,

230 South Dearborn, Chicago, Illinois 60604.

Section 291.204

Meteorological Data

Meteorological data is required for input to the various annual and short-term dispersion

models as well as for the identification of the frequency and duration of conditions when

short-term, high air pollution concentrations may be expected to exist. Hourly

meteorological data shall be acquired from:

Acceptable on-site meteorological monitoring equipment physically located

within the study area or

The nearest National Weather Service weather reporting station which can be

justified as having meteorological conditions representative of the study area.

On-site monitors. To be acceptable, the monitoring site must have been maintained and

operated as a continuous meteorological sensing network designed to determine the wind

and temperature structure controlling downwind transport and the dispersion of

pollutants.

The system shall contain adequate instrumentation for measuring the following

parameters at or near 10 meters above ground-level: wind speed, wind direction

and dry bulb temperature. A determination of the wind speed, wind direction and

air temperature in the mixing layer must have been made at least twice every

24-hour period by use of remote sensing techniques such as pibals, radiosondes,

acoustic sounders or aircraft.

A record of the maintenance and service schedule must be available to allow the

determination of acceptability of on-site meteorological monitoring equipment.

The service and maintenance should have been performed at a frequency

necessary to maintain a minimum of 90% data recovery per parameter per quarter.

Maintenance should have included periodic cleaning, testing and calibration of all

sensors and recorder.

Justification should be submitted with the operating application including that the

meteorological parameters measured at the on-site monitor(s) are representative

of the meteorology in the study area. Included in this justification should be a

discussion of the effects of local terrain, bodies of water, heat islands and any

other conditions which could substantially affect the meteorology of the area.

No on-site monitors. If on-site meteorological monitoring equipment is unavailable or

not selected for use, a justification must be submitted indicating that the meteorological

parameters which are utilized are representative of the study area. Meteorological data

may be obtained from the following sources:

Seasonal and annual wind speed, wind direction, and atmospheric stability. The

National Climatic Center (NCC) in Asheville, North Carolina has wind speed and

wind direction data available as part of hourly or three-hourly weather records.

Data for wind speed and wind direction are combined with atmospheric stability

in a joint frequency distribution called a STAR Program. Various forms of

stability wind rose data are available from NCC in tabular form, on punched

cards, and on magnetic tape. The tapes include the hourly or three-hourly

observations upon which the stability wind rose is based. Five-year, annual,

seasonal and monthly stability wind roses are available.

Mixing height. Climatological summaries of mixing heights based on radiosonde

observations are available in Mixing Height, Wind Speeds, and Potential for

Urban Air Pollution Throughout the Contiguous United States (AP-101) by

George Holzworth of the U.S. Environmental Protection Agency (USEPA). Data

contained in this text are acceptable for utilization with annual dispersion

modeling analyses. Mixing height data for use in determining short-term air

quality levels may be computed from measured meteorological parameters using

the methods outlined in the USEPA's AQMA Guideline Document 10 or the

USEPA's Interim User's Guide to a Computation Technique to Estimate

Maximum 24-Hour Concentrations from Single Sources. Radiosonde observation

data is available for selected meteorological sites from the NCC.

Temperature. Hourly, three-hourly and annual mean temperature records for

meteorological reporting sites are available from the NCC.

Hourly atmospheric stability. The atmospheric stability data may be estimated

from other meteorological parameters by Turner's Method, which is explained in

AQMA Guideline Document 10. The method requires: solar altitude, cloud

cover, ceiling and wind speed. The solar altitude can be obtained from Table 170

entitled "Solar Altitude and Azimuth" in the Smithsonian Meteorological Tables.

Cloud cover and ceiling are available as hourly or three-hourly observations from

the NCC. The solar altitude, time of day, cloud cover and ceiling can be used to

index the solar radiation intesity which, together with the wind speed, determines

the atmospheric stability.

Section 291.205

Air Quality Data

All available ambient air quality monitoring data for the subject pollutant in the study area shall

be assembled by the applicant in a form suitable for comparison with the AAQS and for

calibration of the various air quality simulation models which are a necessary portion of the air

quality study.

Air monitoring data collected by federal, state, or certain local agencies in Illinois may be

obtained from the Division of Air Pollution Control, Illinois Environmental Protection

Agency, 2200 Churchill Road, Springfield, Illinois, 62706. Monitoring data collected by

a governmental agency in a state other than Illinois or by any private industry should be

obtained from the organization responsible for the monitoring site.

Monitoring data which is used by the applicant should have been collected by air

montiroing reference and equivalent methods published by the USEPA in 40 CFR 50

(Appendices) and 40 CFR 53 and revisions thereto or by an equivalent method approved

by the Agency.

Section 291.206

Dispersion Modeling

Several dispersion models are available for determining the annual and short-term

impacts of pollutant emissions on ambient air quality. The dispersion models which are

available from the Agency for use in annual analyses are the Climatological Dispersion

Model (CDM) and the Climatological Dispersion Model revised by the Agency (Revised

CDM). The Agency model available for short-term analyses is the Air Quality

Short-Term Model (AQSTM) developed by the Agency's Division of Air Pollution

Control. All of these models are based on the Gaussian diffusion equation and utilize the

Brigg's plume rise formulae.

Facilities utilizing the models mentioned in subsection (a) to perform the attainment and

maintenance analyses do not need to submit a description of the dispersion and plume

rise formulae other than those listed above, then the following information shall be

submitted to the Agency in support of the techniques which are selected:

A complete computer program listed of the model;

A detailed description of all model equations;

A model flow chart; and

A justification for the use of such model and equations.

Annual Analysis. The basic objective of the annual dispersion analysis is to determine

the maximum ground-level concentrations of sulfur dioxide and total suspended

particulate for comparison with annual air quality standards.

The location of pollutant sources in each facility within the study area shall be

accurately identified so that their relative positions can be input to the dispersion

model.

For the attainment portion of the annual analysis, the average annual controlled

emission rate from each source in the base year and the annual meteorological

parameters determined for the base year shall be utilized. Both the controlled

source emission rates and the meteorological parameters should be valid for the

same one-year period.

The annual analysis for the 1980 projection year and for other Projection years as

deemed necessary by the applicant must be conducted utilizing projected annual

average emissions for the year analyzed and the mean annual meteorological

paramters which have been determined based on historical data from a period of

at least five consecutive years.

Short-Term Analysis. For short term analyses, ground-level concentrations should be

determined for periods of time associated with those meterorological conditions giving

rise to maximum ground-level concentrations, considering the actual physical stack

height and diameter and operating characteristics of the facilities.

Consistent with the annual modeling, the location of the various pollutant

emission sources in each facility affecting the study area must be accurately

identified.

The applicant shall identify those operating conditions leading to the maximum

emissions of sulfur dioxide and/or particulate matter. Specific operating

schedules may be considered in order to determine a reasonable maximum

controlled emission rate for each source affecting the study area (i.e., it is

recognized that all sources may not operate at their maximum levels during the

same time period).

Maximum grid point spacing used in the models shall be 1 kilometer for comparison with

annual standards and 0.1 kilometer for short-term modeling.

The contribution to the point of maximum concentration shall be calculated for each

source of sulfur dioxide (SO(2)) or total suspended particulate (TSP) within the study

area. Sulfur dioxide or TSP ambient air quality monitoring data may be utilized to assist

in establishing background concentrations. Such air quality data should have been

collected for a minimum of 1 year and should be consistent with the ambient air quality

monitoring portion of these procedures.

There are several meteorological situations which might cause sufficiently elevated

ground-level concentrations to threaten the short-term ambient air quality standards. The

following potentially adverse meteorological or physical conditions shall be considered

as a minimum when performing the short-term modeling analyses:

Trapping conditions (for comparison with the 3-hour SO(2) standard and the

24-hour SO(2) and TSP standard).

Mixing height equal to the height of maximum plume rise for that source

at the subject facility or within the study area such that the maximum

ground-level concentration is achieved.

Wind speed equal to 4.4 meters per second at a height of 10 meters above

ground-level.

Atmospheric stability equal to B (unstable).

Wind direction equal to that direction which aligns the emission sources

so as to maximize the ground-level concentrations.

Calculate the maximum 1-hour ground-level concentration using the

dispersion model.

Calculate the minimum 3-hour ground-level SO(2) concentration by

taking the 1-hour concentration in subsection (E) above times 0.80.

Calculate the maximum 24-hour concentration by taking 1/4 of the hourly

concentration calculated in subsection (E) above.

Neutral stability with moderate to high winds (for comparison with the 3-hour

SO(2) standard and the 24-hour SO(2) and TSP standard).

Mixing height equal to 1200 meters.

Stability class equal to D (neutral).

Determine the wind direction which aligns the emission sources such as to

maximize the ground-level concentration of the actual source

configuration.

Determine the critical wind speed (i.e., the wind speed which produces the

maximum ground-level concentration).

Calculate the maximum 1-hour ground-level oncentration using the

dispersion model including background).

Calculate the maximum 3-hour ground-level SO(2) concentration by

taking the 1-hour concentration in subsection (E) above times 0.80.

Calculation of the 24-hour ground-level concentration requires an

examination of actual meteorological conditions collected in the study

area. One technique for calculating the 24-hour ground-level

concentration from the 1-hour concentration is explained on page 38 of the

Workbook of Atmospheric Dispersion Estimates. The method makes the

assumption that the plume is uniformly distributed in the crosswind

direction within a down-wind sector of 22.5 < and may be utilized when

critical wind speed, persistent wind direction, and neutral stability occur

for 16 hours or greater. The 24-hour concentration is obtained by

multiplying the resulting sector concentration by t/24, where t is the

number of hours within a 24-hour period during which the above

meteorological conditions actually occur.

Inversion break-up fumigation (for comparison with the 3-hour SO(2) standard).

Assume that the mixing height is located at ground-level at the beginning

of the 3-hour period for which the maximum ground-level concentration is

being calculated. Allow the mixing height to rise at a rate of 4.88 meters

per minute.

Assume an atmospheric stability class of E (stable) above the height of the

inversion and B (unstable) below the inversion.

Assume a wind speed of 4.4 meters per second at a height of 10 meters

above ground-level.

Determine the wind direction which aligns the emission sources such as to

maximize the ground-level concentration for the actual source

configuration.

Calculate the concentration profile downwind of the facility at 20 minute

intervals. That is, calculate the height of the mixing layer at 20-minute

intervals using the rate of rise given in subsection (A) above. Nine

20-minute average concentrations should be calculated to yield the 3-hour

maximum ground-level concentration.

If the Agency's AQSTM is used to calculate the ground-level

concentration under the fumigation situation, the maximum concentration

will be that concentration computed at a distance of at least x = 4.4

t(subscript m) where x is equal to downwind distance in meters, and

t(subscript m) is equal to the time in seconds required to eliminate the

inversion from the physical stack height to the height of the plume rise.

Any other meteorological conditions experienced in the vicinity of the subject

facility or physical characteristics of the facility or its surroundings which, in the

opinion of the applicant might reasonably be expected to produce maximum

ground-level concentrations in excess of those calculated using the considerations

outlined in subsection (g)(1)-(3).

If meteorological information specific to the subject facility is available, then

such data may be used to modify the procedures outlined in subsection (g)(1)-(4),

as appropriate. However, such meteorological information must have been

collected:

At the site of the subject facility and should be sufficient to determine

wind speed, wind direction, stability class and mixing height; and

During a field study having a minimum duration of one year. Such a

meteorological field study should meet the requirements outlined in these

procedures.

All dispersion models utilized for the annual and short-term analyses should be

calibrated, if possible, with base year ambient air quality monitoring data.

The minimum requirement for model validation shall be the computation of a regression

equaltion (linear, stepwise or non-linear, as appropriate) for observed concentrations vs.

the concentrations calculated by the dispersion model (plus background).

Short-term concentrations should be grouped for like-meteorological conditions

(considering the synoptic meteorological situation).

The regression equation should be applied to each calculated concentration (plus

background) for the appropriate meteorological situations.

The listing of monitored concentrations should be submitted in support of the

proposed emission limitation.

Practical displays of calculated vs. observed concentrations should be submitted

in addition to correlation coefficients and standard errors of estimate.

As deemed necessary by the applicant, additional statistical tests may be used to

evaluate the dispersion modeling results.

Section 291.207

Emission Projection and Allocation Techniques

Generally, the air quality impact analysis procedures use surrogate variables to project

and allocate future point and area source emissions in the study area. It is assumed that

the anticipated growth in emissions will be proportional to the growth in certain surrogate

variables, and will, therefore, be spatially distributed in the study area according to the

spatial distribution of the growth in such variables. The methodology for projecting and

allocating point and area source emissions in the study area is explained in detail in

Volumes 7 and 13 of the USEPA's Guidelines for Air Quality Maintenance Planning and

Analysis. The applicant is strongly urged to obtain and examine these documents

throughly before undertaking an air quality impact analysis.

In undertaking an air quality impact assessment, the applicant should use growth and

development projections which reflect control technology that is realistic for the

projection period and type of source being considered. For example, with respect to

point sources, the applicant should consider Best Available Control Technology (BACT)

Regulations and Guidelines as defined by New Source Performance Standards (40 CFR

60) and as further defined by the USEPA in guidelines for Non Significant Deterioration

(NSD)(40 CFR 52). Also the applicant should consider the application of Reasonably

Available Control Technology (RACT) as defined by Federal guidelines in 40 CFR 51.

In undertaking air quality impact analyses, area source emissions projections at a

sub-county spatial level will be necessary for use in dispersion models. The projections

included in these analyses must be consistent with those projections being used by the

Agency in its continuing air and water quality planning activities.

The Illinois Bureau of the Budget (IBOB) develops official state projections of

population for each county in the state at 5-year increments to the year 2025. State

agenices are constrained to use these figures, plus or minus 5%, for all planning

activities. Variations in excess of 5% must be submitted to the IBOB with detailed

supporting information before such figures will be acceptable to the Agency for inclusion

in a planning analysis.

The Agency has township population projections (which are consistent with IBOB

county control totals) for the entire state to the year 2010. Applicants may use these

figures in lieu of any acceptable alternative figures either derived by the applicants or

obtained from cognizant local and regional planning bodies in the area. Figures other

than those obtained from the Agency should be substantiated by detailed information,

including a description of data base, assumptions, and the methodology used in arriving

at such alternative projections.

To obtain necessary, detailed sub-county information on housing units and structures,

applicants should consult the 1970 Census reports series IIC(3) or PIIC(1). The

publications include maps in which census tracts are overlaid with township boundaries.

This base line data, coupled with the available township population projections, will

provide sufficient information for the applicant to develop forecast-year housing unit

totals.

The IBOB prepares estimates of employment in approximately 200 key industry groups

for 20 multi-county regions consitituting the State of Illinois. Estimates are reported for

base year and 5-year increments up to the year 2000. The "key industry" groupings

roughly correspond to aggregates of 3-digit Standard Industrial Classification (SIC)

categories. In order for an applicant to assess the air quality impact of his source and

those of other major sources within the study area, information on the emissions levels of

existing major sources is required in addition to a growth rate factor to be applied to such

emissions for analysis of future years. Information on current emissions from existing

major sources is available from the Agency. Growth factors for each of these major

sources may be derived by determining the SIC code of any major facility in the study

area, and assigning it the growth rate implicit in IBOB employment projections for the

IBOB industry category in which this practicular SIC code is included. As with the

population projections, the Agency will accept employment projections which deviate

from current IBOB totals, only if such figures are accompanied by a detailed explanation

of data base, assumptions, and methodology, and are concurred in by the IBOB.

Table 3 shows the various categories of emissions and corresponding orders of analysis

possible in an air quality impact study. These categories of analysis are described in

detail in Volume 13 of the USEPA's Guidelines for Air Quality Maintenance Planning

and Analysis. Air quality impact analyses undertaken at the specified level should use

the type and detail of data described in Table 4, unless concurrence from the Agency to

do otherwise is obtained by the applicant. The orders of analyses range from that

requiring the least detail (Order 1) to that requiring the greatest detail (Order 3). The

status of any particular county with respect to the classification scheme in Table 4 may

be obtained from the Division of Air Pollution Control.

Residential Fuel Combustion. Order 1 analyses use population by township,

either obtained from the Agency or developed especially for the air quality impact

study. Order 2 analyses use number of dwelling units by township (or equivalent

sub-county spatial level) within the study area. When a reasonable factor of

number-of-persons-per dwelling-unit is applied to the total number of dwelling

units projected in the study area, the result must be consistent with IBOB

population control totals. Order 3 analysis is refinement upon Order 2, such that

the number of residential structures in the study area is classified according to the

number of dwelling units per structure, similar to that classification outlined on

page 35 of AQMA Guideline Document 13.

Commercial/Institutional Fuel Combustion. Order 1 anlayses are similar to that

for Residential Fuel Combustion. Orders 2 and 3 use employment growth rates to

project and allocate emissions in the study area, using the methodology described

in Guideline Document 13 and the information sources described in the preceding

text.

Industrial Process. All orders of analysis use employment growth rates to project

and allocate emissions in the study area, according to the methodology described

in Guideline Document 13 and sources of information described in the proceding

text.

Industrial Fuel Combustion. Requirements for Orders 1, 2, and 3 of this

emissions category are similar to those for industrial process emissions.

Solid Waste. Estimation and allocation of emissions from the incineration of

solid waste parallel the requirements for Residential, Commercial/Institutional,

and Industrial Process Fuel Combustion for each order of analysis (i.e., the

contribution of each emission source category to solid waste disposal emissions is

determined by using the same indicator variables). For instance, in an Order 1,

analysis of solid waste emissions, the relative contribution of commercial

establishments to total solid waste emissions would be proportional to the growth

in population. Base year figures on emissions in the applicant's study area due to

solid waste disposal are available from the Agency.

SUBPART C: CONTENTS OF THE AIR QUALITY STUDY

Section 291.301

Contents of the Air Quality Study Submitted in Support of a Permit

Application for an SO(2) or TSP Emission Source

The air quality study shall include the following:

A description of the nature and location of the sulfur dioxide or particulate emission

sources at the subject facility, including but not limited to:

Diameter, height, exit gas temperature, and exit gas velocity for all stacks or vents

through which the pollutant is emitted into the atmosphere,

Description of the fuels used to include type, sulfur content, ash content, heat

content, and ultimate analysis,

Description of the type of fuel combustion equipment to include method of firing

and maximum firing rate,

Specific description of the location of the emission sources (Universal Transverse

Mercatur (UTM) coordinates or latitude/longitude) and a plot plan.

A summary of all ambient air quality data collected since January 1, 1973, at monitors

located within a 50-mile radius of the emission source and collected by the owner and/or

operator of the emission source. The summary should include: annual averages;

maximum and second highest short-term averages for each month; and the number of

times the short-term AAQS were exceeded during each month.

A general description of the method by which the air quality study was conducted to

include the method which was used to identify the maximum ground-level concentration

of pollutant contributed to by the subject facility and the location of such maximum

concentration.

A summary of all meteorological data collected by the owner or operator of the emission

source since January 1, 1973, at monitors located within a 50-mile radius of the specified

pollutant emission source provided that such data were used in the development of the

emission limitation.

A description of the justification for all point source data, area source data and

meteorological data which were input to the dispersion models.

An identification of and an estimate as to the frequency, characteristics, probable time of

occurrence and duration of meteorological conditions associated with the maximum

short-term ground-level concentration of the specified pollutant contributed to by the

subject facility. A description of the techniques used in arriving at the above estimates

should be included.

A detailed description and complete listing of all dispersion models and plume rise

equations which were used to develop the emission limitation to include all model

equations. This is not necessary if CDM and the AQSTM are exclusively utilized as

received from the Agency, except that a statement that CDM and the AQSTM were used

should be included.

A detailed description of the method that was used to determine total background

pollutant concentrations in the vicinity of the subject facility for the annual model and for

each of the meteorological conditions considered in performing the analysis is such

background concentrations are different than those given in Section 291.103.

A detailed description of all dispersion model validation and calibration procedures to

include the regression equations, correlation coefficients and other statistical data which

indicate the reliability of the modeling results for the various situations modeled.

A detailed description of the technique used to allocate area source emissions from the

county level to the sub-county level.

A detailed description of the technique used to project growth for the maintenance

period.

A statement of the base year used for the analysis and the reasons for selection of the

base period.

Detailed maps of the study area which include: topographic features, bodies of water,

and locations of point and area sources.

Data tables which include but are not limited to:

Short-term and annual background concentrations which were determined for all

meteorological conditions considered in the air quality study,

Calculated ground-level concentrations, calibrated and uncalibrated, from all

short-term and annual dispersion modeling.

The type, number and location of meteorological monitoring devices from which data

was obtained for use in performing the study including a discussion of the suitability of

the location of such monitors.

The type, number and location of instruments for the continuous monitoring and

recording of pollutant emissions which were used by the subject facility to determine

emissions for use in the study.

A description of the system and procedures used for acquisition and storage of ambient

air quality, meteorological and emissions data.

A description of the procedures utilized for validation of air quality, meteorological and

emissions data for use in the study.

Identification of company personnel responsible for use performance of the air quality

study so as to provide a point of contact.

An explicit statement of the emission limitation which is proposed for the source.

Section 291.APPENDIX A Rule into Section Table

Rule

Section

1.0

291.101

2.0

291.102

3.0

291.103

4.1

291.201

4.2

291.202

4.3

291.203

4.4

291.204

4.5

291.205

4.6

291.206

4.7

291.207

5.0

291.301