A bill to amend the Clean Air Act to revise the standard for the application of title I of the Act to modifications of facilities which emit or may emit any air pollutant.

Amends the Clean Air Act to revise the definition of "modification" of a source or facility, for purposes of the provisions of such Act concerning the prevention of significant deterioration of air quality, to mean any physical change in, or change in the operation of, a stationary source which increases the net amount of any pollutant emitted by such stationary source by either 100 tons per year or more for a major emitting facility, or by 250 tons per year or more for any other stationary source.

Revises the definitions of "modifications" and "modified", for purposes of the provisions of such Act concerning plan requirements for nonattainment areas, to mean any physical change in (including a complete replacement), or a change in the method of operation of, a stationary source which increases the net amount of any air pollutant emitted by such stationary source, or which results in the emission of any air pollutant not previously emitted by such stationary source by 100 tons per year or more.