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EPA’s decision to reconsider National Ambient Air Quality Standards for ozone is a long-awaited step in the right direction

October 28, 2021 Work Area: Power Plants

The Environmental Protection Agency’s decision to reconsider the National Ambient Air Quality Standards (NAAQS) for ozone is “a long-awaited step in the right direction,” according to Hayden Hashimoto, attorney for Clean Air Task Force, which represents several other non-profit environmental organizations in the matter. The NAAQS must be set at a level that protects public health with an adequate margin of safety, and it is particularly important that the standard be set at a level that protects sensitive groups. The previous administration disregarded compelling scientific evidence supporting strengthening the level of the ambient ozone standard, and we are pleased that the Biden EPA has decided to revisit this issue.”

Ground-level ozone, which forms in the air when pollutants produced by combustion chemically react in the presence of sunlight, can cause respiratory problems, especially for people with lung diseases, including asthma and chronic bronchitis. The elderly and children playing outdoors are also particularly vulnerable.

The American Lung Association’s 2021 State of the Air report found that more than 123 million Americans lived in counties that experienced repeated instances of unhealthy levels of ozone in the air. Climate change is likely to exacerbate this problem by causing more hot sunny days that are conducive to high ozone levels.

The World Health Organization’s guideline level for ozone, which was recently reviewed and retained, is set at an 8-hour daily maximum of 100 µg/m3 or about 50 ppb, which is far below the current NAAQS standard of 70 ppb, which dates from 2015. During that last review process, EPA’s Clean Air Scientific Advisory Committee (CASAC), which was able to utilize the expertise of an external review panel, noted that setting the standard at 70 ppb, while more protective than the prior level of the standard, would provide little margin of safety, and advised the Administrator to set the standard lower than 70 ppb within a range down to 60 ppb.

At the time, CASAC noted substantial scientific evidence of adverse effects at 70 ppb, including decrease in lung function, increase in respiratory symptoms, and increase in airway inflammation.

Hashimoto continued: “We encourage EPA to move expeditiously. The Agency must conduct a thorough review, and set the ozone NAAQS at a level that protects public health with the adequate margin of safety required by the Clean Air Act. It is particularly important that the standard be set at a level that protects at-risk populations, including children, people with asthma, and the elderly.”


Press Contact: Stuart Ross, Communications Director, sross@catf.us, +1 914-649-5037

About Clean Air Task Force

Clean Air Task Force (CATF) is a non-profit organization working to safeguard against the worst impacts of climate change by catalyzing the rapid global development and deployment of low-carbon energy and other climate-protecting technologies. We work towards these objectives through research and analysis, public advocacy leadership, and partnership with the private sector. With nearly 25 years of nationally and internationally recognized expertise on clean air policy and regulations and a fierce commitment to fully exploring all potential solutions, CATF is an environmental advocacy group with the bold ideas needed today to solve the climate crisis. CATF is headquartered in Boston, with staff working virtually around the U.S. and abroad.

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