Source Definition Examples Stationary: Major Emissions of 10 tons per year or more of any one air toxic, or 25 tons per year or more of any combination of air toxics Utilities, refineries, steel manufacturers, chemical manufacturers Area Emissions of less than 10 tons per year of any one air toxic pollutant, or less than 25 tons per year of any combination of air toxics Dry cleaners, gas stations, auto body refinishing paint shops, decorative chromium electroplating operations Mobile: On-road Emissions from motorized vehicles normally operated on public roadways Cars, buses, sport-utility vehicles, light- and heavy- duty trucks Non-road Emissions from a diverse collection of engines, equipment, vehicles, and vessels operated off public roads Construction and agricultural equipment, personal watercraft, lawn and garden equipment