Classification of regions.

The Alaska plan was evaluated on the basis of the following classifications: Air quality control Region Pollutant Particulate matter Sulfur oxides Nitrogen dioxide Carbon monoxide Ozone Cook Inlet Intrastate I III III I III. Northern Alaska Intrastate I III III I III. South Central Alaska Intrastate III III III III III. Southeastern Alaska Intrastate III III III III III. [37 FR 10848, May 31, 1972, as amended at 48 FR 30625, July 5, 1983]