Illinois Administrative Code

Section 203.1070 Baseline Actual Emissions "Baseline actual emissions" means the rate of emissions, in tons per year, of a regulated NSR pollutant, as determined in accordance with subsections (a) through (d). a) For any existing electric utility steam generating unit, baseline a…

Section 203.1080 Begin Actual Construction "Begin actual construction" means in general, initiation of physical on-site construction activities on an emissions unit that are of a permanent nature. Such activities include, but not limited to, installation of building supports and …

Section 203.1090 Building, Structure, Facility, or Installation a) "Building, structure, facility, or installation" mean all of the pollutant-emitting activities which belong to the same industrial grouping, are located on one or more contiguous or adjacent properties, and are un…

Section 203.110 Available Growth Margin "Available growth margin" means the portion which remains of any emission allowance for new or modified major stationary sources expressly identified in the attainment demonstration approved by the United States Environmental Protection Age…

Section 203.1100 Commence "Commence," as applied to construction of a major stationary source or major modification, means that the owner or operator has all necessary preconstruction approvals or permits and either has: a) Begun, or caused to begin, a continuous program of actua…

Section 203.1110 Complete "Complete" means, in reference to an application for a permit, that the application contains all of the information necessary for processing the application. (Source: Added at 49 Ill. Reg. 6237, effective April 23, 2025)

Section 203.112 Building, Structure and Facility a) The terms "building", "structure", and "facility" include all of the pollutant-emitting activities which belong to the same industrial grouping, are located on one or more contiguous or adjacent properties, and are under the con…

Section 203.1120 Construction "Construction" means any physical change or change in the method of operation (including fabrication, erection, installation, demolition, or modification of an emissions unit) that would result in a change in emissions. (Source: Added at 49 Ill. Reg.…

Section 203.113 Commence As applied to construction of a major stationary source or major modification "commence" means that the owner or operator has obtained all necessary preconstruction approvals or permits and either has: a) Begun, or caused to begin, a continuous program of…

Section 203.1130 Dispersion Technique a) "Dispersion technique" means any technique that attempts to affect the concentration of a pollutant in the ambient air by: 1) Using the portion of a stack that exceeds good engineering practice stack height; 2) Varying the rate of emission…

Section 203.1140 Electric Utility Steam Generating Unit "Electric utility steam generating unit" means any steam electric generating unit that is constructed for the purpose of supplying more than one-third of its potential electric output capacity and more than 25 MW electrical …

Section 203.1150 Emission Offset "Emission offset" means a creditable emissions reduction used to compensate for the increase in emissions resulting from a new major stationary source or a major modification in accordance with Section 203.1810. (Source: Added at 49 Ill. Reg. 6237…

Section 203.116 Construction "Construction" means any physical change or change in the method of operation, including but not limited to fabrication, erection, installation, demolition, or modification of an emissions source unit, which would result in a change in actual emission…

Section 203.1160 Emissions Unit "Emissions unit" means any part of a stationary source that emits or would have the potential to emit any regulated NSR pollutant and includes an electric utility steam generating unit as defined in Section 203.1140. For purposes of this Part, ther…

Section 203.117 Dispersion Enhancement Techniques "Dispersion Enhancement Techniques" mean so much of the stack height of any source as exceeds good engineering practice or any other dispersion technique, determined by regulations at 40 CFR 51.100 (1987) (no future amendments or …

Section 203.1170 Excessive Concentration "Excessive concentration" is defined for the purposes of determining good engineering practice stack height under Section 203.1200(a)(3) and means: a) For sources seeking credit for stack height exceeding that established under Section 203…

Section 203.1180 Federally Enforceable "Federally enforceable" means all limitations and conditions which are enforceable by the USEPA, including those requirements developed pursuant to 40 CFR Parts 60, 61, 62 and 63 (incorporated by reference in Section 203.1000), requirements …

Section 203.119 Emission Baseline "Emission baseline" means the starting point or reference level from which increases and decreases in emissions are measured. The rules governing determination of emission offsets, calculations of net emission increases, and evaluation under 35 I…

Section 203.1190 Fugitive Emissions "Fugitive emissions" means those emissions which could not reasonably pass through a stack, chimney, vent or other functionally equivalent opening. (Source: Added at 49 Ill. Reg. 6237, effective April 23, 2025)

Section 203.1200 Good Engineering Practice a) "Good engineering practice", with respect to stack height, means the greater of: 1) 65 meters, measured from the ground-level elevation at the base of the stack; 2) The following: A) For a stack in existence on January 12, 1979, and f…

Section 203.121 Emission Offset "Emission offset" means a creditable emission reduction used to compensate for the increase in emissions resulting from a new major source or a major modification in accordance with Sections 203.302 and 203.303 of this Part. (Source: Section 203.12…

Section 203.1210 Lowest Achievable Emission Rate "Lowest Achievable Emission Rate" or "LAER" means, for any source, the more stringent rate of emissions based on the following: a) The most stringent emissions limitation which is contained in the implementation plan of any State f…

Section 203.122 Emissions Unit "Emissions unit" means any part of a stationary source which emits or has the potential to emit any air pollutant subject to regulation under the Act or this Chapter or by the United States Environmental Protection Agency under the Clean Air Act (42…

Section 203.1220 Major Modification a) Except as provided in subsections (d) through (f) below, "major modification" means any physical change or change in the method of operation of a major stationary source that would result in: a significant emissions increase (as defined in S…

Section 203.123 Federally Enforceable "Federally enforceable" means enforceable by the United States Environmental Protection Agency. (Source: Former Section 203.123 renumbered to Section 203.122, new Section 203.123 added at 17 Ill. Reg. 6973, effective April 30, 1993)

Section 203.1230 Major Stationary Source a) The following constitute a major stationary source: 1) For an area designated as nonattainment for ozone, a major stationary source for ozone is a stationary source which emits or has the potential to emit VOM in an amount equal to or g…

Section 203.124 Fugitive Emissions "Fugitive Emissions" means those emissions which could not reasonably pass through a stack, chimney, vent or other functionally equivalent opening. (Source: Added at 12 Ill. Reg. 6118, effective March 22, 1988)

Section 203.1240 Nearby "Nearby", with respect to a specific structure or terrain feature: a) For purposes of applying the formula provided in Section 203.1200(a)(2), means that distance up to five times the lesser of the height or the width dimension of a structure, but not grea…

Section 203.125 Installation "Installation" means an identifiable piece of equipment, including, but not limited to, boilers, furnaces, reactors, dryers, incinerators, heaters, and coating lines. (Source: Former Section 203.125 renumbered to Section 203.126, new Section 203.125 a…

Section 203.1250 Necessary Preconstruction Approvals or Permits "Necessary preconstruction approvals or permits" mean those permits or approvals required under federal air quality control laws and regulations and those air quality control laws and regulations which are part of th…

Section 203.126 Lowest Achievable Emission Rate "LAER" is an acronym for lowest achievable emission rate. (Source: Amended at 17 Ill. Reg. 6973, effective April 30, 1993)

Section 203.1260 Net Emissions Increase a) "Net emissions increase" means, with respect to any regulated NSR pollutant emitted by a major stationary source, the amount by which the sum of the following exceeds zero: 1) The increase in emissions from a particular physical change o…

Section 203.127 Nonattainment Area An area designated by USEPA as nonattainment for a given pollutant pursuant to Section 107 of the Clean Air Act (42 U.S.C. 7407). (Source: Added at 12 Ill. Reg. 6118, effective March 22, 1988)

Section 203.1270 Nonattainment Area An area designated by the USEPA as nonattainment for a given pollutant under section 107 of the CAA (42 U.S.C. 7407) in Subpart C of 40 CFR Part 81. (Source: Added at 49 Ill. Reg. 6237, effective April 23, 2025)

Section 203.128 Potential to Emit "Potential to emit" means the maximum capacity of a stationary source to emit a pollutant under its physical and operational design. Any physical or operational limitation on the capacity of the source to emit a pollutant, including air pollution…

Section 203.1280 Nonattainment New Source Review (NA NSR) Permit "Nonattainment New Source Review permit" or "NA NSR permit" means a permit or a portion of a permit for a new major source or major modification that is issued by the Agency under the construction permit program req…

Section 203.1290 Potential to Emit "Potential to emit" means the maximum capacity of a stationary source to emit a pollutant under its physical and operational design. Any physical or operational limitation on the capacity of the source to emit a pollutant, including air pollutio…

Section 203.1300 Process Unit "Process unit" means any collection of structures and/or equipment that processes, assembles, applies, blends, or otherwise uses material inputs to produce or store an intermediate or completed product. A process unit may contain more than one emissi…

Section 203.131 Reasonable Further Progress "Reasonable Further Progress" means the annual incremental reductions in the emissions of the applicable air pollutant as determined by USEPA pursuant to Part D of the Clean Air Act (42 U.S.C. 7501 et seq.) and federal regulations adopt…

Section 203.1310 Project "Project" means a physical change in or change in the method of operation of an existing major stationary source. (Source: Added at 49 Ill. Reg. 6237, effective April 23, 2025)

Section 203.1320 Projected Actual Emissions a) "Projected actual emissions" means the maximum annual rate, in tons per year, at which an existing emissions unit is projected to emit a regulated NSR pollutant in any one of the 5 years (12-month period) following the date the unit …

Section 203.1330 Reasonable Further Progress "Reasonable further progress" means the annual incremental reductions in the emissions of the pollutant as determined by the USEPA pursuant to Part D of Title I of the CAA (42 U.S.C. 7501 et seq.) and federal regulations adopted pursua…

Section 203.134 Secondary Emissions "Secondary Emissions" means the emissions which would occur as a result of the construction or operation of a major stationary source or major modification, but do not come from the major stationary source or major modification itself. For the …

Section 203.1340 Regulated NSR Pollutant "Regulated NSR pollutant" means the following: a) NOX or VOM; b) Any pollutant for which a NAAQS has been promulgated; c) Any pollutant that is identified under this Section as a constituent or precursor of a general pollutant listed under…

Section 203.1350 Replacement Unit "Replacement unit" means an emissions unit for which all the criteria listed in subsections (a) through (d) are met. No creditable emissions reductions shall be generated from shutting down the existing emissions unit that is replaced. a) The emi…

Section 203.136 Stationary Source "Stationary Source" means any building, structure, facility or installation which emits or may emit any air pollutant subject to regulation under the Act or this Chapter or by USEPA under the Clean Air Act (42 U.S.C. 7401 et seq.). (Source: Added…

Section 203.1360 Secondary Emissions "Secondary Emissions" means emissions which would occur as a result of the construction or operation of a major stationary source or major modification, but do not come from the major stationary source or major modification itself. Secondary e…