U.S. Code of Federal Regulations
Regulations most recently checked for updates: Aug 27, 2025
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 |
