40 CFR 52.721: Classification of regions.

The Illinois plan was evaluated on the basis of the following classifications:

Air quality control region Pollutant

Particulate matter Sulfur oxides Nitrogen dioxide Carbon monoxide Ozone

Burlington-Keokuk Interstate I I III III III

East Central Illinois Intrastate III II III III III

Metropolitan Chicago Interstate (Indiana-Illinois) I I I I I

Metropolitan Dubuque Interstate I III III III III

Metropolitan Quad Cities Interstate I III III III III

Metropolitan St. Louis Interstate (Missouri-Illinois) I I III I I

North Central Illinois Intrastate II IA III III III

Paducah (Kentucky)-Cairo (Illinois) Interstate I II III III III

Rockford (Illinois)-Janesville-Beloit (Wisconsin) Interstate II III III III III

Southeast Illinois Intrastate III II III III III

West Central Illinois Intrastate I IA III III III