Abstract: The Environmental Protection Agency (EPA) compiles data on emission tonnages of air pollutants for US counties.  US Air Quality Gradebook ("AirGrades") source sheets give the percentage contributions from specific air pollution sources.  This source sheet is for

Granite County, Montana; Hill County, Montana; and Jefferson County, Montana.  The Granite County Seat is Philipsburg, Montana; the Hill County Seat is Havre, Montana; and the Jefferson County Seat is Boulder, Montana.