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

Livingston County, Michigan; Luce County, Michigan; and Mackinac County, Michigan.  The Livingston County Seat is Howell, Michigan; the Luce County Seat is Newberry, Michigan; and the Mackinac County Seat is Saint Ignace, Michigan.