52.2621—Classification of regions.
The Wyoming 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) | |
| Cheyenne Intrastate | II | III | III | III | III |
| Casper Intrastate | II | III | III | III | III |
| Wyoming Intrastate | III | III | III | III | III |