40 CFR 52.1221: Classification of regions.

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

Air quality control region Pollutant

Particulate matter Sulfur oxides Nitrogen dioxide Carbon monoxide Photochemical oxidants (hydrocarbons)

Central Minnesota Intrastate II III III III III

Southeast Minnesota-La Crosse (Wisconsin) Interstate II Ia III III III

Duluth (Minnesota)-Superior (Wisconsin) Interstate I II III III III

Metropolitan Fargo-Moorhead Interstate II III III III III

Minneapolis-St. Paul Intrastate I I III I III

Northwest Minnesota Intrastate II III III III III

Southwest Minnesota Intrastate III III III III III