National Wildlife Refuge System

Sources of Air Quality

Various air pollutants can cause detrimental effects on sensitive park resources. These include pollutants emitted directly from sources (primary pollutants) and those that are formed as a result of chemical reactions in the atmosphere (secondary pollutants). Primary pollutants include, sulfur dioxide, nitrogen oxides, particulate matter, and volatile organic compounds, while secondary pollutants include sulfates, nitrates, and ozone.


Types of Pollution Sources

Sources of Air pollution include: "stationary sources" such as power plants, industrial facilities, and factories; "mobile sources" such as cars, buses, planes, trucks, and trains; "natural sources" such as wind-blown dust, wildfires, and volcanoes. The following graphic outlines the major pollutant sources, transport, transformations, deposition, and effects.

Emissions and Effects

Sources vary in quantity and categories across the United States, this results in varying concentrations of pollutants. Within the Air Quality in Refuges pages detail air pollution affecting each of the twenty-one Class 1 refuges.

Last updated: June 16, 2015