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Area Designations for the 2012 Annual Fine Particle (PM2.5) Standard


March 31, 2015 - EPA is establishing or revising initial area designations and a technical amendment to correct an inadvertent error in the initial designation for one area for the 2012 annual national ambient air quality standards for fine particle pollution. Learn more

December 18, 2014 – EPA issued final designations for most areas of the country for the 2012 annual fine particle standard. Learn more


This Web site provides information on the process EPA, the states and the tribes engage in to designate areas as "nonattainment" (not meeting) the annual PM2.5 standard established in 2012.

The Clean Air Act requires EPA to issue designations after the agency sets a new National Ambient Air Quality Standard (NAAQS) or revises an existing standard. EPA formally designates areas as “nonattainment” (not meeting the standard), “unclassifiable/attainment” (meeting the standard or expected to be meeting the standard despite a lack of monitoring data), or “unclassifiable” (insufficient data to classify).

Once nonattainment designations take effect, the state and local governments must develop implementation plans outlining how areas will attain and maintain the standards by reducing air pollutant emissions contributing to fine particle concentrations.   

This Web site contains the following information:

State Designations: EPA has issued final designations for most states.  The status of this effort is summarized here.

Tribal Designations: EPA has issued final designations for areas of Indian Country.  The status of this effort is summarized here. 

Frequent Questions: Answers to common questions regarding fine particles and the designations process.

Designations Guidance and Data: Data and tools for States and Tribes that may be useful in the annual PM2.5 NAAQS designation process.

PM2.5 Conditions: Links to the AirNOW Web site with real-time information on PM2.5 conditions and web cameras around the country.

Air Quality Forecast: Links to the Air NOW Web site with PM2.5 air quality forecasts for dozens of cities around the country. 

Basic Information: Background on PM2.5 attainment issues and EPA actions to address PM2.5 emission concerns.

PM and Human Health: Information about the health effects of particle pollution. 

Related Links: Related sites offering further information and assistance.

Glossary: Explanations of the technical terms and acronyms used throughout the site.

EPA has similar sets of web pages for ozone designations, nitrogen dioxide (NO2) designations, sulfur dioxide (SO2) designations, and lead (Pb) designations.


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