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

Judith Basin County, Montana; Lake County, Montana; and Lewis And Clark County, Montana.  The Judith Basin County Seat is Stanford, Montana; the Lake County Seat is Polson, Montana; and the Lewis And Clark County Seat is Helena, Montana.