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Ground-level Ozone Pollution

Technical Data and Reports on Ozone Measurements and SIP Status

EPA collects data from the states and regions on their air quality and state implementation plan (SIP) progress. This information is compiled in a database, and used to create reports, trend charts, and maps.

SIP Status for Nonattainment (Designated Area) Requirements

About these reports: If an area is designated as "nonattainment" (designated areas), states must develop a SIP that details the path to attain and maintain the National Ambient Air Quality Standards (NAAQS). Certain Northeast states, known as the Ozone Transport Region (OTR), must also submit a SIP for the pollutants that form ozone.

 See also: Where to find EPA actions on SIP submittals in the Federal Register.

Air Quality and Emissions Data 

  • Status and trends of key air pollutants - EPA tracks the levels of criteria air pollutants and how much of each pollutant is emitted from various pollution sources.
  • Design values - A design value is a statistic that describes the air quality status of a given location relative to the level of the NAAQS.
  • AirNow - Current air quality index.
  • AirData - Historical air quality data.
  • National Emissions Inventory Interactive Report - Explains how air emissions data are generated and used as well as provides tools that explore emission trends and source contributions to air pollution.


  • Ozone Designations: This web site provides information on the process EPA, the states, and the tribes follow to designate areas as "attainment" (meeting) or "nonattainment" (not meeting) the ground-level ozone standards.
  • Green Book: listings of areas designated nonattainment for each NAAQS pollutant. It includes current designation and classification status, area maps, reports, and Federal Register notices.