These are the common air pollutants regulated by the EPA under the Clean Air Act. They are also known as primary air pollutants because they are emitted directly from sources and have significant impacts on human health and the environment.
Primary air pollutants are those emitted directly from a source, while secondary pollutants form when primary pollutants react in the atmosphere. The EPA's criteria air pollutants include both types, chosen based on their widespread presence and known health impacts.
Check Your Local Air QualityCreated by chemical reactions between NOx and VOCs in sunlight.
Mixture of solid particles and liquid droplets in the air.
Colorless, odorless gas from incomplete combustion.
Primarily from fossil fuel combustion at power plants.
Forms from emissions from cars, power plants, and off-road equipment.
Emissions from industrial sources and contaminated soil.