52.1821—Classification of regions.
The North Dakota 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) | |
| Metropolitan Fargo-Moorhead Interstate | II | III | III | III | III |
| North Dakota Intrastate | II | III | III | III | III |