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AirCompare - Frequently Asked Questions

Why doesn’t AirCompare include information on air toxics (hazardous air pollutants)?
AirCompare focuses on pollutants covered by EPA’s Air Quality Index. These include ground-level ozone, particle pollution (also known as particulate matter), carbon monoxide, sulfur dioxide, and nitrogen dioxide. Information on air toxics, including estimates of population exposure, is available through EPA’s National-scale Air Toxics Assessment (NATA).

Why can't I select a county from the map?
AirCompare shows results only for counties that have monitoring data.  Counties without monitoring data appear gray in the map and cannot be selected.  Note that some of these counties could be part of a nonattainment area, even though they lack monitoring data. For a list of nonattainment counties by pollutant, visit EPA’s Greenbook.

Can I get information about pollen and mold on this site? Use this site to get information about air pollution in different areas -- including ozone and particle pollution. Information on pollen and mold is available from the American Academy of Allergy Asthma & Immunology. Exit EPA disclaimer


AIRNow is a government-backed program. Through AIRNow, EPA, NOAA, NPS, news media, tribal, state, and local agencies work together to report conditions for ozone and particle pollution. State, Local and Tribal Partners.
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