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EPA makes final attainment designations for 2015 National Ambient Air Quality Standards for Ozone - Designations for Over 400 Counties Remain Outstanding

On November 6, the U.S. Environmental Protection Agency (EPA) released a partial list of counties that will not be impacted by the yet-to-be implemented 2015 National Ambient Air Quality Standards (NAAQS) for Ozone. EPA also indicated that attainment designations for the remaining counties will be announced at a later date. The move is in response to a rule finalized in 2015, which lowered the NAAQS for ozone from 75 parts per billion (ppb) to 70 ppb.

EPA’s decision is based off recommendations made by the individual states last fall. In the notice, the agency stated that most areas of the country – 2,646 counties overall – either meet the 2015 standards for ground-level ozone or are unclassifiable. The agency also announced that while it is not ready to issue designations for the remaining areas of the country, it would continue to work with those states and localities to determine these designations. In short, EPA’s announcement means that designations for about 420 counties remain outstanding, and EPA has yet to provide an official timeline for completing them.

Under the Clean Air Act, the EPA Administrator is required to make all attainment designations within two years after a final rule revising the NAAQS is published. However, the deadline for EPA Administrator Pruitt to issue designations for the 2015 NAAQS for ozone passed on October 1. As a result, numerous groups have already notified EPA of their intent to sue, setting the stage for litigation in the coming weeks absent further action from EPA.

Ozone is one of the six air pollutants regulated by the Clean Air Act (CAA) NAAQS program. Under NAAQS, EPA is required to reassess air quality standards every five years. Primarily known as a summertime pollutant, ozone forms when sunlight reacts with pollutants such as volatile organic compounds emitted from chemical plants, gasoline pumps, oil-based paints, and auto body and print shops. Sources of nitrogen oxides (NOx) include power plants, industrial facilities and motor vehicles. 

Ozone designations can have a significant impact on county governments. Under the Clean Air Act, states and counties serve as co-regulators with the federal government and are ultimately responsible for the implementation of new and existing air quality standards. 227 counties are currently regulated under ozone air quality standards, yet the new 70 ppb standard is expected to increase the number of impacted counties to over 350.

NACo has called on EPA to delay implementation of the 2015 ozone standards until the 75ppb standard set in 2008 can be fully analyzed for impact, and will continue to work closely with Congress and the Trump Administration to craft clear, concise and workable rules that take into account the role of counties as key regulatory partners with the federal government.

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