EPA finalizes ozone NAAQS, retains current standards

The U.S. Environmental Protection Agency (EPA) on Dec. 23 announced its decision to retain, without changes, the 2015 ozone National Ambient Air Quality Standards (NAAQS) set by the Obama-Biden Administration.

The EPA said it is following the principles established by the Trump Administration to streamline the NAAQS review process and to fulfill the statutory responsibility to complete the NAAQS review within five years. The action marks the second time in Clean Air Act history that the agency has completed an ozone NAAQS review within the congressionally mandated five-year timeframe, according to the EPA.

The agency noted that since the beginning of the Trump Administration, it has re-designated eight nonattainment areas  as in attainment with the 2008 eight-hour ozone standards.

In May 2018, EPA issued a “Back-to-Basics” memo to improve EPA’s process for reviewing the NAAQS. The memo laid out goals to get EPA back on track with Clean Air Act requirements, statutory deadlines, and the issuance of timely implementation rules. The Dec. 23 action is the first NAAQS review to do so and charts a path to continue this statutory responsibility in the future.   

The Clean Air Act requires EPA to set NAAQS for “criteria pollutants.” Currently, ozone and related photochemical oxidants and five other major pollutants are listed as criteria pollutants.

The law requires EPA to periodically review the relevant scientific information and the standards and revise them, if appropriate, to ensure that the standards provide the requisite protection for public health and welfare.

In the prior review of the ozone standards, which was completed in 2015, the Obama-Biden EPA increased the stringency of the levels of the ozone standards to 70 parts per billion (ppb), from the 2008 standard of 75 ppb.

Additional information about EPA ozone standards is available at: https://www.epa.gov/ground-level-ozone-pollution. APPA submitted comments in support of retaining the 2015 primary (public health) and secondary (public welfare) standards at 70 ppb.

EPA is making the ozone NAAQS rule legally effective upon publication, and the rule is almost certain to be challenged in court.