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The AirData Web site provides access to yearly summaries of United States air pollution data, taken from EPA's air pollution databases.


Environmental Protection Agency (EPA)

Data Years Available



The Environmental Protection Agency (EPA) conducts a national inventory of air pollutant emissions at three-year intervals, and adds the new data to the National Emission Inventory database. Between inventories, EPA refines and corrects the emissions data, and updates the database several times. Data are extracted for use in AirData approximately once per year. The Air Quality System (AQS) database is updated at least weekly. Most states submit their air monitoring data monthly, with different groups of states submitting data during any given week. Around the beginning of each month, criteria air pollutant summary values for the current year and ten previous years are extracted from the AQS database for presentation in AirData reports.



Selected Content

AirData has information about where air pollution comes from (emissions) and how much pollution is in the air outside our homes and work places (monitoring). Monitoring sites report data to EPA for these six criteria air pollutants: Carbon monoxide (CO), Nitrogen dioxide (NO2), Ozone (O3) , Sulfur dioxide (SO2), Particulate matter (PM10 and PM2.5), and Lead (Pb). EPA collects emissions data for three criteria air pollutants: Carbon monoxide (CO), Sulfur dioxide (SO2), Particulate matter (PM10 and PM2.5) and three precursors/promoters of criteria air pollutants: Volatile organic compounds (VOC), Nitrogen oxides (NOx), Ammonia (NH3) .

Population covered

The data include all fifty states plus District of Columbia, Puerto Rico, and the U. S. Virgin Islands.


AirData draws information from two EPA databases: EPA's National Emission Inventory (NEI) database, and The Air Quality System (AQS) database.

Response rate and sample size


Interpretation Issues

Some values may be absent due to incomplete reporting and some values may be subsequently changed due to quality assurance activities. Also, some values in reports and maps may be slightly out of date. Readers are cautioned not to infer a qualitative ranking order of geographic areas as pollution levels measured in the vicinity of a particular monitoring site may not be representative of a county or urban area. AirData reports should not be used to deduce trends without confirming that EPA used equivalent estimation methods for the years being monitored.