40 CFR 52.1971 - Classification of regions.

The Oregon plan was evaluated on the basis of the following classifications:

Air quality control region	Pollutant					Particulate matter	Sulfur oxides	Nitrogen dioxide	Carbon monoxide	Ozone	Portland Interstate	I	IA	III	I	I	Southwest Oregon Intrastate	II	III	III	III	III	Northwest Oregon Intrastate	III	III	III	III	III	Central Oregon Intrastate	II	III	III	III	III	Eastern Oregon Intrastate	II	III	III	III	III

[37 FR 10888, May 31, 1972, as amended at 45 FR 42278, June 24, 1980]