Despite clear recommendations from its own science advisors, the US Environmental Protection Agency (EPA) announced over the summer that it will delay its scheduled process to consider strengthening public health standards for ground-level ozone pollution. The announcement is the latest development in a long-running saga over this air pollutant, which is the main component of smog. As a result, the public will continue to be unnecessarily exposed to ozone levels that may be hazardous to their health for at least a few more years, an outcome especially harmful to communities currently overburdened by air pollution.
The decision to delay comes on the heels of draft recommendations released just a few months earlier by EPA’s Clean Air Scientific Advisory Committee (CASAC) that recommended lowering the primary standard from the current level of 70 parts per billion (ppb) to 55-60 ppb. CASAC is a panel of independent scientific experts that provides technical guidance on EPA’s national air quality standards. CASAC’s recommendations were based on an exhaustive review of the scientific evidence about the effects of ozone exposure, including EPA’s own findings about the public health effects.
The stakes over ground-level ozone standard are high. Ozone is one of six “criteria air pollutants” for which EPA is required to establish National Ambient Air Quality Standards (NAAQS). These air pollutants are commonly emitted across the nation and can harm public health and the environment. Unlike the beneficial ozone in the Earth’s upper atmosphere that protects us from the sun’s ultraviolet rays, ground-level ozone is created from chemical reactions between pollutants—mostly those emitted by cars, power and chemical plants, and refineries.
Breathing ground-level ozone, which is a colorless gas, can cause serious respiratory issues and aggravate existing lung diseases, such as asthma. EPA’s troubling decision to sidestep science-based recommendations to adopt a stronger standard will unnecessarily result in thousands of cases of asthma exacerbations and other respiratory illnesses.
A political tug of war
Historically, efforts to strengthen the ground-level ozone standard have been undermined by political and corporate motivations. Administrations under the previous three US presidents have all ignored CASAC’s recommendations, setting weaker standards. In particular, the Trump administration went so far as to dismiss a panel of experts tasked with advising on the development of the ozone standard and to remove independent scientists in CASAC. The administration’s actions led to a deeply flawed rulemaking process that ignored the science and maintained the existing standard.
The Biden administration had the opportunity to rectify the previous administration’s actions to sideline science in the process of updating the ground-level ozone standard. However, EPA staff continued to advocate for maintaining the 70 ppb level despite CASAC’s unequivocal stance for years that a more protective standard is needed to safeguard public health.
In August, EPA Administrator Michael Regan decided to scrap the process for updating the ground-level ozone standard altogether and start anew. While the reasons for this delay remain unclear, the decision essentially sanctions the continued use of the less protective standard for at least another two years.
According to EPA’s proposed timeline, the agency plans to convene a public science and policy workshop in spring 2024 to gather input on the latest available science related to ozone exposure, and release its Integrated Review Plan by the fall. The Integrated Review Plan presents EPA’s proposed approach for completing an updated review of scientific information related to ground-level ozone. This delayed timeline runs headfirst into the 2024 election, and if a more hostile administration assumes leadership, we may have to wait at least four more years before EPA adopts an evidence-based ground-level ozone standard that is set at a level to help eliminate disparities in ozone exposure.
In response to EPA’s disappointing decision, attorneys in states including New York and California are pursuing legal action to challenge the agency’s 2020 decision to maintain the existing standard.
Major implications for public health
EPA’s decision to delay flies in the face of robust science supporting a more protective standard for ground-level ozone. While CASAC’s recommendations may seem like a small shift, decreasing the standard by 10 ppb could have measurable benefits for public health. A 2012 study found that decreasing the ozone standard from 75 ppb (the standard at the time) to 60 ppb could avoid up to 8,000 ozone-related premature deaths per year. In 2015, the American Thoracic Society cited several studies documenting adverse respiratory health effects at levels of exposure exceeding 60 ppb.
According to the American Lung Association, more than 30 percent of the US population are regularly exposed to hazardous levels of ozone. In the US, BIPOC populations, especially Black and Asian people, are more likely to be exposed to ozone than white populations. A breadth of research shows that concentrated air pollution contributes to greater risk of premature death in non-white populations, in large part due to the cumulative impacts of environmental and social stressors foisted upon these communities. Without a doubt, current NAAQS standards have measurably protected public health and decreased air pollution exposure across the nation. However, without a stronger ground-level ozone standard, overburdened communities in particular will continue to bear the burden of inadequate protections.
The science is clear, yet EPA has decidedly failed Americans by passing the buck on adopting science-based protections from ozone pollution. Communities, especially those that grapple with the compounding harms of air pollution, deserve better.