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

[37 FR 10862, May 31, 1972, as amended at 39 FR 16346, May 8, 1974; 45 FR 11493, Feb. 21, 1980]