40 CFR 52.2021: Classification of regions.

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

Air quality control region Pollutant

Particulate matter Sulfur oxides Nitrogen dioxide Carbon monoxide Ozone (hydrocarbons)

Metropolitan Philadelphia Interstate I I III I I

Northeast Pennsylvania-Upper Delaware Valley Interstate I II III III III

South Central Pennsylvania Intrastate I II III III III

Central Pennsylvania Intrastate I III III III III

Southwest Pennsylvania Intrastate I I III I I

Northwest Pennsylvania-Youngstown Interstate I II III III III