The Michigan plan was evaluated on the basis of the following classifications:
| Air quality control region
| Pollutant
|
|---|
| Particulate matter
| Sulfur oxides
| Nitrogen dioxide
| Carbon monoxide
| Ozone
|
|---|
| Metropolitan Detroit-Port Huron Intrastate | I | I | III | III | III
|
| Metropolitan Toledo Interstate | I | I | III | III | I
|
| South Central Michigan Intrastate | II | II | III | III | III
|
| South Bend-Elkhart (Indiana)-Benton Harbor (Michigan) Interstate | I | IA | III | III | III
|
| Central Michigan Intrastate | II | III | III | III | III
|
| Upper Michigan Intrastate | III | III | III | III | III |