The Oklahoma plan was evaluated on the basis of the following classifications:
Air quality control region | Pollutant | ||||
Particulate matter | Sulfur oxides | Nitrogen dioxide | Carbon monoxide | Ozone | |
Central Oklahoma Intrastate | I | III | III | III | I |
Northeastern Oklahoma Intrastate | I | III | III | III | I |
Southeastern Oklahoma Intrastate | III | III | III | III | III |
North Central Oklahoma Intrastate | III | III | III | III | III |
Southwestern Oklahoma Intrastate | III | III | III | III | III |
Northwestern Oklahoma Intrastate | III | III | III | III | III |
Metropolitan Fort Smith Interstate | II | III | III | III | III |
Shreveport-Texarkana-Tyler Interstate | II | III | III | III | III |
40 C.F.R. §52.1921