EPA pushes controversial air pollution limits

In an effort to reverse Trump-era environmental policies, the Biden administration is proposing new rules aimed at significantly reducing smog-forming emissions and microscopic air pollutants.

The proposed restrictions, put forward by the Environmental Protection Agency (EPA), would reduce cross-state smog-forming emissions from power plants by up to 29 percent and cut fine air particulates by one-third. They could also result in billions of dollars in implementation costs for power plants and other industrial emission sources, from chemical plants to glass manufacturers. Yet some experts in air quality science and policy believe the proposed pollution restrictions lack scientific evidence and are even based on misinterpretations of air quality data.

The EPA’s so-called “Good Neighbor Plan,” announced earlier this month, targets 26 states producing smog-forming pollutants called nitrogen oxides that cross state lines. Nitrogen oxides contribute to the creation of ground-level ozone, which in turn produces smog. Ozone is one of six air pollutants the EPA regulates: In 2015, the EPA lowered the ozone standard to 70 parts per billion, down from 75 parts per billion. If the new proposal is approved, power and other industrial plants will face new emissions standards beginning in 2026, costing them about $1.1 billion, according to an EPA estimate.

The agency is also in the final stages of tightening air quality standards for airborne particulates less than 2.5 micrometers in diameter. Such pollutants, referred to as “PM2.5,” are about 30 times smaller than the width of a human hair. The EPA’s Clean Air Scientific Advisory Committee (CASAC) recommended earlier this month that the PM2.5 annual average be lowered to 8-10 micrograms per cubic meter, down from 12. While the agency has not released a cost estimate for implementing new PM2.5 standards, similar restrictions under the Obama administration were estimated to cost up to $33 billion annually.

The EPA predicts that the newly proposed ozone regulations will prevent 1,000 premature deaths, 2,000 hospital visits, and 1.3 million asthma cases by 2026. The additional restrictions to PM2.5 come without an estimate of the health benefits. In its March 18 review, CASAC stated: “The current level of the annual standard is not sufficiently protective of public health and should be lowered.”

But not all researchers share the administration’s view. Tony Cox, a risk analyst who chaired CASAC during the Trump administration, described the EPA’s projected health benefits as “wishful thinking.” He pointed to a comprehensive review published in 2020 of 42 studies that found no clear association between reductions in air pollution and reductions in mortality or respiratory hospitalizations. During Cox’s tenure, the committee chose not to further restrict air pollutant emissions.

Cox points to problems with the EPA’s determination that certain levels of air pollutants cause respiratory health problems. In a commentary in Global Epidemiology in November 2020, Cox wrote that it is sloppy science to assume a causal relationship between air pollution and mortality without investigation of alternative explanations. He noted that air pollution and mortality rates could be correlated over time due to coincident trends, or that confounding variables  — including poverty or daily temperature extremes in the weeks before death — could explain the observed association.

James Enstrom, a retired professor of epidemiology at UCLA, said the EPA has disregarded evidence contrary to its claims about mortality linked to current air pollutant levels. In a letter to the CASAC panel, Enstrom listed 61 researchers who raised objections and were not included in the agency’s September 2021 assessment of PM2.5’s health effects.

CASAC members Lianne Sheppard and Jennifer Peel directed my inquiries about the matter to the EPA’s press office, which declined to comment.

Enstrom also critiqued media portrayals of PM2.5 emissions. “They always show pictures of soot, smoke coming out of smokestacks. But you can’t see 10 micrograms,” he said. “The dose is so tiny that you’d have trouble, no matter what it was, making a case that it could cause death.”

Another confounding factor is that air pollution has already dropped dramatically since the 1990s, as shown in the EPA’s own database, calling into question the need for more severe regulations.

Ozone concentration levels decreased by 33 percent between 1980 and 2020, according to the EPA, while PM2.5 levels have decreased by 41 percent since 2000. Daren Bakst, a regulatory policy expert at the Heritage Foundation, noted that messaging surrounding air pollution in the United States distracts from the fact that the country has some of the cleanest air in the world. “I just think there’s a lot of scare tactics out there, on ozone especially, and [particulate matter],” he said. In some parts of the country, the natural background levels of ozone are already high, leaving little room for further improvements.

Both of the proposals to restrict air pollutants came after Biden’s EPA administrator, Michael Regan, removed Trump-appointed members of the EPA’s Science Advisory Board and CASAC. A lawsuit is currently challenging that move, claiming Regan violated federal law by opening up membership to researchers previously barred because they received EPA funding.

Bakst thinks the advisory board reset was intended to cherry-pick scientists already biased towards stricter air pollutant standards. “It gives a certain appearance that they know what policy result they want,” he said.