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Nomenclature changes to part 52 appear at 81 FR 74586, Oct. 26, 2016.
The Washington plan was evaluated on the basis of the following classifications:
| Air quality control region | Pollutant | ||||
|---|---|---|---|---|---|
| Particulate matter | Sulfur oxides | Nitrogen dioxide |
Carbon monoxide |
Ozone | |
| Eastern Washington-Northern Idaho Interstate | I | IA | III | III | III |
| Northern Washington Intrastate | II | III | III | III | III |
| Olympic-Northwest Washington Intrastate | II | II | III | III | III |
| Portland Interstate | I | IA | III | III | III |
| Puget Sound Intrastate | I | IA | III | III | I |
| South Central Washington Intrastate | I | III | III | III | III |
[81 FR 1131, Jan. 11, 2016]