81.23—Southwest Pennsylvania Intrastate Air Quality Control Region.
The Southwest Pennsylvania Intrastate Air Quality Control Region is redesignated to consist of the territorial area encompassed by the boundaries of the following jurisdictions or described area (including the territorial area of all municipalities (as defined in section 302(f) of the Clean Air Act, 42 U.S.C. 1857h(f)) geographically located within the outermost boundaries of the area so delimited):
In the State of Pennsylvania: Allegheny County, Armstrong County, Beaver County, Butler County, Greene County, Fayette County, Indiana County, Washington County, Westmoreland County.