Illinois Administrative Code (Last Updated: February 21, 2024) |
TITLE35. ENVIRONMENTAL PROTECTION |
PART204. PREVENTION OF SIGNIFICANT DETERIORATION |
SUBPARTF. REQUIREMENTS FOR MAJOR STATIONARY SOURCES AND MAJOR MODIFICATIONS IN ATTAINMENT AND UNCLASSIFIABLE AREAS |
§204.1120. Air Quality Models
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a) All estimates of ambient concentrations required under this Section shall be based on applicable air quality models, databases, and other requirements specified in 40 CFR 51, appendix W (Guideline on Air Quality Models) (incorporated by reference in 35 Ill. Adm. Code 204.100).
b) When an air quality model specified in 40 CFR 51, appendix W (Guideline on Air Quality Models) (incorporated by reference in Section 204.100) is inappropriate, the model may be modified or another model substituted. Such a modification or substitution of a model may be made on a case-by-case basis or, where appropriate, on a generic basis for a specific State program. Written approval of USEPA must be obtained for any modification or substitution. In addition, use of a modified or substituted model must be subject to notice and opportunity for public comment under procedures set forth in 35 Ill. Adm. Code 252.