Point: Point sources are large, stationary (non-mobile), identifiable sources of emissions that release pollutants into the atmosphere. Examples include large industries, such as manufacturing plants, power plants, paper mills, refineries, but can also include portable sources such as some asphalt or rock crushing operations and gas stations.
Area Source: Area sources collectively represent sources which individually are too small in magnitude to report as point sources. Examples include residential heating, commercial combustion, asphalt paving, and commercial and consumer solvent use.
Event Sources: Event sources include fires that are reported in a day-specific format such as wildfires and prescribed burns. Generally, the US EPA calculates these emissions using a satellite detection approach combined with fire models and activity data provide by State, Local, and Tribal air agencies or forestry agencies.
Biogenic Source: Biogenic emissions are all pollutants emitted from nonanthropogenic sources. Example sources include trees and vegetation, oil and gas seeps, and microbial activity.
Mobile Source: Onroad sources include emissions from onroad vehicles that use gasoline, diesel, and other fuels. These sources include light duty and heavy duty vehicle emissions from operation on roads, highway ramps, and during idling. Nonroad sources include off-road mobile sources that use gasoline, diesel, and other fuels. Source types include construction equipment, lawn and garden equipment, aircraft ground support equipment, locomotives, and commercial marine vessels.
