Emission Inventory Documentation

This page last reviewed February 11, 2013



Southern California from orbit (NASA photo)

Air pollution comes from a wide variety of sources. It comes from large industrial facilities, as well as from things we use in our daily lives such as cars and trucks, paints, and aerosol spray products. For convenience, we have grouped air pollution sources into five major categories that are listed below.


Mobile Sources

On-Road Sources
Sources of on-road air pollution include automobiles, motorcycles, and trucks. Emission Data


Off-Road Sources
Off-road mobile sources include the following categories: small off-road engines and equipment, off-road recreational vehicles, farm and construction equipment, forklifts, locomotives, commercial marine vessels, and marine pleasure craft. Emission Data


Stationary Sources
Stationary sources of air pollution include non-mobile sources such as power plants, refineries, and manufacturing facilities. Emission Data


Areawide Sources
Areawide sources of pollution are those where the emissions are spread over a wide area, such as consumer products, fireplaces, road dust, and farming operations. Emission Data


Natural Sources
Natural sources are non-manmade emission sources, which include biological and geological sources, wildfires, windblown dust, and biogenic emissions from plants and trees. Emission Data




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