On Dec. 23, the United States Environmental Protection Agency (EPA) declared that it had finalized its five-year review of ozone National Ambient Air Quality Standards (NAAQS), retaining the same standards put in place by the Obama-Biden Administration. The press release noted that this is only the second time in Clean Air Act (CAA) history that the agency has met the congressionally-mandated time frame for addressing ozone standards.
The decision, the EPA said, came after thorough review of the latest available scientific evidence and technical information, consultation with the EPA’s independent science advisors, and consideration of more than 50,000 public comments submitted. The rule keeps in place the former ozone standards that, when initiated in 2015, limited the permissible concentration of ozone from 75 parts per billion (ppb) to 70 ppb.
The press release also noted that since President Trump’s ascension to office, the EPA has “re-designated to attainment eight nonattainment areas for the 2008 8-hour ozone standards.” Over the same period, the announcement stated, domestic nitrogen oxide emissions have dropped 10%, volatile organic compound emissions 3%, and ozone concentrations 4%. Since 1990, the EPA explained, national average ozone concentrations have fallen 25%.
As to the timeliness of the agency’s action, the press release partly credited a May 2018 agency-issued memorandum entitled “Back-to-Basics,” aimed at streamlining the EPA’s process for reviewing the NAAQS. EPA Administrator Andrew Wheeler touted the agency’s punctuality and remarked that “[o]ur actions today show [that] the Trump Administration is fulfilling its promise of protecting human health and environment for all Americans, regardless of where they live.”