Illinois Administrative Code › Title 35 - ENVIRONMENTAL PROTECTION › Part 291 - RULES FOR THE PERFORMANCE OF AIR QUALITY IMPACT ANALYSES TO BE USED IN SUPPORT OF PERMIT APPLICATIONS › Subpart B - ELEMENTS OF THE AIR QUALITY ANALYSIS › Section 291.207 - Emission Projection and Allocation Techniques

Current through Register Vol. 48, No. 28, July 12, 2024
a) 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.
b) 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.
c) 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.
d) 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.
e) 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.
f) 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.
g) 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.
h) 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.
1) 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 a 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.
2) 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.
3) 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.
4) Industrial Fuel Combustion. Requirements
				for Orders 1, 2, and 3 of this emissions category are similar to those for
				industrial process emissions.
5)
				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.