U.S. Code of Federal Regulations
Regulations most recently checked for updates: Aug 27, 2025
The Tennessee 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) | |
| Eastern Tennessee-Southwestern Virginia Interstate | I | I | III | III | III |
| Tennessee River Valley-Cumberland Mountains Intrastate | I | I | III | III | III |
| Middle Tennessee Intrastate | I | II | III | III | I |
| Western Tennessee Intrastate | I | III | III | III | III |
| Chattanooga Interstate | I | II | III | III | III |
| Metropolitan Memphis Interstate | I | III | III | III | I |
