EPA Officials Sideline Scientists When Establishing Particulate Matter Air Pollution Standard

Published Oct 28, 2022

What Happened: Political officials sidelined Environmental Protection Agency (EPA) scientists and disregarded the science on potential health risks caused by fine particulate matter pollution. These actions led to a finalized National Ambient Air Quality Standard (NAAQS) for particulate matter that the best available science suggests is less protective for human health.

Why It Matters: By sidelining scientists, the EPA failed to utilize the best available science to develop evidence-based environmental and public health protections. Instead of using the best available science to safeguard communities from harmful air pollution, especially those that are disproportionately impacted, EPA political officials prioritized political considerations over science.

Environmental Protection Agency (EPA) officials under the Trump administration sidelined scientists that stated the best available science showed that the existing National Ambient Air Quality Standard (NAAQS) for particulate matter 2.5 micrometers or less in diameter (PM2.5) is hazardous and therefore more stringent NAAQS measures for PM2.5 are required to protect public health. Specifically, EPA scientists wrote in a draft policy assessment that the best available science suggested that the annual particulate matter standard should be tightened to between 8 and 10 micrograms per cubic meter and they cited evidence suggesting that reducing the limit to 9 micrograms per cubic meter could save between 9,050 and 34,600 lives a year. When EPA scientists presented this policy assessment to EPA administrator Andrew Wheeler, Wheeler claimed that evidence that they presented was insufficient and that there was no the need to tighten the standards for particulate matter. This led the EPA to finalize a NAAQS for PM2.5 that kept the previous standards in place, despite the body of evidence showing that this will lead to public health and environmental harms.

The current NAAQS for PM2.5 was enacted in 2012, which set the annual standard for air pollution from fine-particulate matter to 12 micrograms per cubic meter of air. Recent research strongly suggests that lowering the standard to a more protective limit of nine micrograms per cubic meter of air could reduce the risks of adverse health effects such as heart attack, stroke, and death that result from long-term PM2.5 exposure.

In 2020, particulate matter was estimated to cause over 100,000 deaths a year in the US. PM2.5 is an air pollutant that can reduce visibility and cause the air to appear hazy when pollution levels are elevated. These particles pose a huge threat to the public as they can be inhaled deep into the lungs. Research studies have demonstrated that these particles cause severe damage to the human respiratory system, posing an even greater threat to those who have pre-existing conditions such as heart or lung disease. Researchers at the Harvard University T.H. Chan School of Public Health conducted an analysis of over 3,000 US counties and discovered that COVID-19 patients who were chronically exposed to elevated levels of PM2.5 were associated with higher mortality rates.

A series of unprecedented attacks occurred during the Trump administration on what were supposed to be independent scientific processes to evaluate the health effects of PM2.5 exposure. This included the dissolvement of the PM Review Panel, the Clean Air Scientific Advisory Committee (CASAC) openly admitting that it lacked expertise to evaluate PM2.5 standards, and CASAC considering an approach that would have limited the types of epidemiological studies used to assess the health risks of air pollution. A full timeline of these attacks can be viewed here. In 2019, the Union of Concerned Scientists hosted a meeting to reconvene the PM Review Panel that was previously disbanded, and the panel overwhelming stated that the current PM2.5 standards do not protect public health.

Communities of color and low-income communities historically have been disproportionately overburdened by pollution from neighboring industrial facilities. A 2019 study by the Union of Concerned Scientists found that on average, communities of color in the Northeast and Mid-Atlantic breathe 66 percent more air pollution from vehicles than white residents and that white residents make up 85 percent of the total populations of people living in areas with the lowest PM2.5 pollution. A 2021 study found that communities of color on average had exposure rates almost 3x higher than communities with white residents. The lack of implementation of stricter environmental protections from the EPA contributes to the continuous, systemic PM2.5 exposure disparity experienced by marginalized communities.

The decision-making process on setting air pollution standards should be guided by independent science and it is required to do so under the Clean Air Act. When the agency ignores the best available science, the government is less able to reduce hazards to the public health and the environment from particulate matter pollution. This is especially detrimental to underserved communities, Black, Indigenous, low-income, and communities of color, who experience higher levels of PM pollution and often have only minimal protections available to safeguard their health. The EPA is responsible for protecting human health but under the Trump administration the agency endangered the health and safety of people across the nation by sidelining federal scientists to appeal to political considerations.