40 CFR 52.1021 - Classification of regions.

Regulations last checked for updates: Feb 12, 2026

Title 40 - Protection of Environment last revised: Dec 22, 2026

§ 52.1021 - Classification of regions.

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

Air quality control region	Pollutant
Air quality control region	Particulate matter	Sulfur oxides	Nitrogen dioxide	Carbon monoxide	Ozone
Metropolitan Portland Intrastate	I	II	III	III	III
Androscoggin Valley Interstate	IA	IA	III	III	III
Down East Intrastate	IA	IA	III	III	III
Aroostook Intrastate	III	III	III	III	III
Northwest Maine Intrastate	III	III	III	III	III

[37 FR 10870, May 31, 1972, as amended at 45 FR 10774, Feb. 19, 1980]

authority: 42 U.S.C. 7401

cite as: 40 CFR 52.1021