VOCs (Volatile Organic Compounds) generally come from evaporated petroleum products. The main sources of VOCs are pesticides and fertilizers, motor vehicles, farming operations, petroleum production facilities, surface coatings, and solvents.

NOx (Nitrogen Oxides) come from fuel combustion, both in motor vehicles and industrial processes. Power plants, factories, cars, trucks, and stationary engines all create NOx.

Particulate matter (PM) comes from dirt roads, farming operations, industrial crushing and grinding, and windblown dust, among other sources. Combustion of fossil fuels, as well as burning garbage and agricultural products, also releases particulate matter into the air. Additionally, PM can be formed when chemicals such as NOx, sulfur dioxides, and others (including many of the same that form ozone) react and condense in the atmosphere.

Emissions Inventory
For detailed information on sources of pollution in a specific region of California, visit the California Air Resources Board's emission inventory website.

 

Compare emissions inventories for selected California regions:

• Sacramento Valley Air Basin
• San Francisco Bay Area Air Basin
• San Joaquin Valley Air Basin