Construction and other industry groups welcomed the U.S. Environmental Protection Agency’s proposal to retain the national air quality standard for ozone at 70 parts per billion (ppb), the level established in 2015 by the Obama administration.

According to EPA, ozone concentrations fell 4% from 2017 to 2019. Moreover, since 2016, 13 communities designated to be in “non-attainment” with the 2008 eight-hour ozone standards have been re-designated to be in compliance.

“Based on a review of the scientific literature and recommendation from our independent science advisors, we are proposing to retain existing ozone standards which will ensure the continued protection of both public health and the environment,” Wheeler said in his July 13 announcement.

Ground-level ozone, often generated by exhaust from cars and trucks, is created when pollutants chemically react in the presence of sunlight. It is a key component of smog.

The announcement comes on the heels of EPA’s April proposal to retain the national ambient  air quality standards (NAAQS) for soot at levels set during the Obama administration.

Public health organizations say they are disappointed that the administration did not propose a more stringent standard for ozone. They noted that the 70 ppb set in 2016 was a compromise: EPA’s own Clean Air Scientific Advisory Committee had recommended in 2014 that the level be set to between 60 and 70 ppb.

Public health advocates had fought for 60 ppb then, and they say there is even more evidence that 70 ppb is “not adequate.”  In a joint statement, the American Lung Association, American Public Health Association and other medical groups said: “EPA’s proposal ignores the long-standing wealth of scientific evidence pointing to the need for a more protective standard.”

Some of that evidence includes research published in 2017 in the Journal of the American Medical Association suggesting that ozone pollution causes increased mortality at levels even below 70 ppb, the health groups said.

Nick Goldstein, vice president of regulatory and legal issues at the American Road and Transportation Builders Association, says that new air quality standards need time to work. Because the Clean Air Act requires that NAAQs be reviewed for both particulate matter and ozone every five years, communities barely have time to work toward meeting new standards before the review process begins again.  The evidence cited by EPA shows that air quality is improving under the existing standard, Goldstein says.

Counties deemed to be in non-attainment can have federal transportation funding withheld, which can lead to uncertainty and delays on construction projects.

The American Chemistry Council agreed, saying the current standard will protect public health without hobbling the U.S. economy. In a statement, the council said the proposal would “provide the U.S. Business of Chemistry—an industry sector responsible for more than 25% of U.S. GDP—much needed regulatory certainty.”