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EPA, Working with States and Tribes, Makes Final Attainment Designations for 2015 Ozone NAAQS

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EPA Press Office (

WASHINGTON (November 6, 2017) — Consistent with the states’ and tribes’ recommendations, the U.S. Environmental Protection Agency (EPA) is moving forward with designations for close to 90 percent of the country. EPA will continue to work with the remaining areas on their designations.

“Today’s action shows our commitment to working with our state and tribal partners on one of the most important areas of EPA’s work – ensuring that more Americans are living and working in areas that meet national air quality standards,” said EPA Administrator Scott Pruitt. “The ozone designation process is complex and requires ongoing and extensive conversations with state and local agencies.  As we move forward, the Agency will be able to prioritize, be more responsive to local needs, and move forward on a case-by-case basis.”

After EPA establishes or revises an air quality standard, the Agency follows a process, dictated by the Clean Air Act, by which states recommend area designations to EPA.  The Agency then evaluates their recommendations prior to making its final designations.

Since the Clean Air Act Amendments of 1990 – passed with bipartisan support to address concerns with regard to pollutants – there has been tremendous progress in implementing these reforms. National monitored levels of ozone have dropped 22 percent, all while our population, energy use and GDP have increased.  

The Clean Air Act provides in Section 107(d)(1)(B) that the Administrator has two years from promulgation of revised NAAQS (October 1, 2015) to promulgate designations. Consistent with states’ and tribes’ recommendations, EPA finds that most areas of the country -- 2,646 of the more than 3,100 counties in the United States -- meet the standards for ground-level ozone. These areas do not have any increased compliance burdens.

For the remaining areas, EPA is not extending the time provided under section 107 of the Clean Air Act, but is not yet prepared to issue designations.  In the spirit of cooperative federalism, EPA will continue to work with states and the public to help areas with underlying technical issues, disputed designations, and/or insufficient information. Additionally, EPA modeling, state agency comments, and peer-reviewed science indicate international emissions and background ozone can contribute significantly to areas meeting attainment thresholds. The agency intends to address these areas in a separate future action.

In June, EPA Administrator Pruitt sent a letter to governors to inform them that EPA is extending the deadline for promulgating initial area designations, by one year, for the 2015 NAAQS for ozone. In August, EPA announced that the Agency would be moving forward with the 2015 ozone designations on a case-by-case basis.  This replaced and clarified EPA’s path forward, providing states the long-term certainty they need.

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