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

Niobrara County, Wyoming; Park County, Wyoming; and Platte County, Wyoming.  The Niobrara County Seat is Lusk, Wyoming; the Park County Seat is Cody, Wyoming; and the Platte County Seat is Wheatland, Wyoming.