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Air Quality System


The Air Quality System (AQS), formerly the Aerometric Information Retrieval System (AIRS), is the Environmental Protection Agency's (EPA) repository of ambient air quality data. AQS stores data from over 10,000 monitors, 5,000 of which are currently active. The system contains ambient air pollution data collected by EPA, state, local, and tribal air pollution control agencies.  AQS also contains meteorological data, descriptive information about each monitoring station (including its geographic location and its operator), and data quality assurance/quality control information.  The Office of Air Quality Planning and Standards (OAQPS) and other AQS users rely upon the system data to assess air quality, assist in Attainment/Non-Attainment designations, evaluate State Implementation Plans for Non-Attainment Areas, perform modeling for permit review analysis, and other air quality management functions.  AQS information is also used to prepare reports for Congress as mandated by the Clean Air Act.

Environmental Protection Agency
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EPA regulations require state environmental agencies to report air monitoring data at least quarterly. Data for one calendar quarter are due to EPA by the end of the following quarter.

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Some values may be absent due to incomplete reporting, and some values may be subsequently changed due to quality assurance activities.