40 CFR 52.2321 - Classification of regions.

Regulations last checked for updates: Feb 12, 2026

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

§ 52.2321 - Classification of regions.

The Utah 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	Photochemical oxidants (hydrocarbons)
Wasatch Front Intrastate	I	I	I	I	I
Four Corners Interstate	IA	IA	III	III	III
Utah Intrastate	III	III	III	III	III

[37 FR 10898, May 31, 1972, as amended at 39 FR 16347, May 8, 1974]

cite as: 40 CFR 52.2321