The Idaho plan was evaluated on the basis of the following classifications:
| Air quality control region
| Pollutants
|
|---|
| Particulate matter
| Sulfur oxides
| Nitrogen dioxide
| Carbon monoxide
| Ozone
|
|---|
| Eastern Idaho Intrastate | I | II | III | III | III.
|
| Eastern Washington Northern Idaho Interstate (Idaho) | I | II | III | III | III.
|
| Idaho Intrastate | I | III | III | III | III.
|
| Metropolitan Boise Intrastate | II | III | III | I | III. |