The EPA announced a proposal to retain the current 70 ppb National Ambient Air Quality Standard (NAAQS) for ozone, set in 2015. The agency reported that ozone concentrations have fallen by 4% from 2017 to 2019.
EPA’s proposal to retain the 70ppb standard comes at the recommendation of the Clean Air Scientific Advisory Committee (CASAC). Under the Clean Air Act, EPA is required to review the NAAQS standard every five years and consider the most current available scientific evidence, and risk and exposure information before making any revisions to the standard.
In their press release, EPA reported that “as a result of Clean Air Act, programs and efforts by state, local, and tribal governments, from 1990-2019, U.S. emissions of nitrogen oxides and volatile organic compounds – air pollutants that contribute to the formation of ground-level ozone – have dropped by 65 percent and 47 percent respectively. During that same time, national average ozone concentrations have dropped 25 percent.”
EPA will be accepting comment on this proposed decision for 45 days after it is published in the Federal Register. For more information, see https://www.epa.gov/ground-level-ozone-pollution/ozone-national-ambient-air-quality-standards-naaqs.
The TCC Air Conservation Committee will discuss prospective comments for submission to EPA, and in coordination with the American Chemistry Council and other industry stakeholders.
NAAQS Background from EPA
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, EPA increased the stringency of the levels of the ozone standards to 70 parts per billion (ppb), from the 2008 standard of 75 ppb.
If you have any questions about this update, please contact Sam Gammage, TCC General Counsel at gammage@texaschemistry.org or 512-646-6403.
