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EPA, Working with States and Tribes, Takes Next Steps on 2015 Ozone Designations

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WASHINGTON  – Highlighting its commitment to collaborating with states, tribes, and localities to protect air quality, the U.S. Environmental Protection Agency (EPA) is taking the next step in the Clean Air Act process to implement the national air quality standards for ozone that were issued in 2015. After designating most of the United States as meeting the standards in November 2017, the Agency is now completing nearly all remaining area designations. Eight counties in the San Antonio, Texas area will be designated by July 17, 2018.

“Following the data and the law, today’s designations reflect continued progress in addressing ground-level ozone and its precursors,” said EPA Administrator Scott Pruitt. “EPA will continue to work closely with our state and tribal partners to improve air quality for all Americans.”

After carefully considering state recommendations, today’s action identifies 51 nonattainment areas in 22 states and the District of Columbia. In identifying these areas, the Agency acknowledges the role played by background ozone that is outside the control of state and tribal air agencies. These designations also reflect the exclusion of certain data due to “exceptional events.”

In addition, today’s action includes two tribal areas designated as nonattainment separately from the surrounding state. EPA has designated Duval County, Florida as “unclassifiable.” All remaining areas are designated attainment/unclassifiable.

Continued Progress

Compared to designations issued in 2012 for the 2008 standards, there are more than 10 percent fewer counties being designated “nonattainment” for the more stringent 2015 standard. Ozone levels have dropped by more than 20 percent since 1990. Emissions of ozone precursors have fallen even more dramatically since 2000, with nitrogen oxide emissions down more than 50 percent and volatile organic compound emissions down more than 20 percent.

Implementing Air Quality Standards

After EPA sets a new National Ambient Air Quality Standard, or revises an existing standard, the Clean Air Act requires EPA to determine if areas across the country meet the new or revised standards and states and tribes submit recommendations to the EPA for each area in the state.   

After working with both states and tribes and considering air quality data and other information, EPA “designates” areas of the country as “nonattainment” if it is not meeting the standard or contributes to a violation in a nearby area. Most other areas are designated attainment or unclassifiable. In a few cases where air quality monitoring is available but incomplete, EPA designates an area as “unclassifiable.” 

Once areas are designated, state and local governments must develop implementation plans outlining how these areas will attain the standards by reducing air pollutant emissions. EPA will continue to support states and local agencies in their planning process as they determine the best methods to meet and maintain these Clean Air Act standards.

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