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

Code of Federal Regulations

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