Classification of regions.

The West Virginia plan was evaluated on the basis of the following classifications: Air quality control region Pollutant Particulate matter Sulfur oxides Nitrogen dioxide Carbon monoxide Photochemical oxidants (hydrocarbons) Steubenville-Weirton-Wheeling Interstate I I III III III Parkersburg-Marietta Interstate I II III III III Huntington-Ashland-Portsmouth-Ironton Interstate I III III III III Kanawha Valley Intrastate I III III III III Southern West Virginia Intrastate III III III III III North Central West Virginia Intrastate I III III III III Cumberland-Keyser Interstate I I III III III Central West Virginia Intrastate III III III III III Allegheny Intrastate III III III III III Eastern Panhandle Intrastate III III III III III [37 FR 10902, May 31, 1972]