40 CFR 52.821 - Classification of regions.

The Iowa plan was evaluated on the basis of the following classification:

Air quality control region	Pollutant					Particulate matter	Sulfur oxides	Nitrogen dioxide	Carbon monoxide	Photochemical oxidants (hydrocarbons)	Metropolitan Omaha-Council Bluffs Interstate	I	II	III	III	III	Metropolitan Sioux Falls Interstate	II	III	III	III	III	Metropolitan Sioux City Interstate	III	III	III	III	III	Metropolitan Dubuque Interstate	I	III	III	III	III	Metropolitan Quad Cities Interstate	I	III	III	III	III	Burlington-Keokuk Interstate	I	I	III	III	III	Northwest Iowa Intrastate	III	III	III	III	III	North Central Iowa Intrastate	IA	III	III	III	III	Northeast Iowa Intrastate	I	III	III	III	III	Southwest Iowa Intrastate	III	III	III	III	III	South Central Iowa Intrastate	I	III	III	III	I	Southeast Iowa Intrastate	III	III	III	III	III

[37 FR 10865, May 31, 1972, as amended at 39 FR 16346, May 8, 1974]