EPA science advisers unanimously back tighter soot limits

By Sean Reilly | 03/04/2022 04:28 PM EST

The decision of just how much to tighten the standards now lies in the hands of EPA Administrator Michael Regan, who plans to move forward with a proposed rule by this summer. The decision has been described as “one of the biggest public health decisions that the administrator will make.”

Smokestack emissions are seen at the Jeffrey Energy Center coal-fired power plant near Emmett, Kan.

Smokestack emissions are seen at the Jeffrey Energy Center coal-fired power plant near Emmett, Kan. AP Photo/Charlie Riedel

It’s not a question of whether national soot standards will be tightened, but by how much — a decision with sizable implications for Americans’ health and industry regulations.

The choice is now up to EPA Administrator Michael Regan.

This afternoon, an agency advisory panel unanimously approved a series of recommendations for Regan to consider in setting new standards that in one key specific go beyond the conclusions of EPA career staff. All seven members of the Clean Air Scientific Advisory Committee endorsed a cut in the annual exposure limit, while most also backed a reduction in the daily standard.


The vote capped three days of virtual meetings over the past week as the committee hammered out a final version of draft recommendations released last month (Greenwire, Feb. 7). Regan plans to issue a proposal by this summer, with a final rule following by spring of next year.

This “is one of the biggest public health decisions that the administrator will make and we really appreciate the very careful and detailed advice,” Erika Sasser, head of EPA’s health and environmental impacts division, told the committee afterward.

While most of the resulting changes to the draft appeared to be relatively minor, the committee softened a provision of keen interest to state and local regulators: that EPA “revisit” its traditional treatment of wildfire-related pollution as “exceptional events” that don’t necessarily count against an area’s compliance record.

At least in part because of climate change, those blazes have emerged as an increasingly virulent air quality threat, with smoke fouling the air for days at a time in normally pristine Western locales.

The provision’s intent was to ask EPA “do to the rethinking, not to tell them what to think or what to decide,” Lianne Sheppard, the committee’s chair and a biostatistics professor at the University of Washington, said earlier this week.

But it drew objections from Jim Boylan, a senior official with Georgia’s Environmental Protection Division, who noted that EPA evaluates requests for exceptional events waivers on a case-by-case basis and had spent a long time developing its current framework. “So I definitely don’t think the sentence should stay as it is,” Boylan said. Instead, the provision now says that EPA “should consider the implications of the exceptional events approach when applied to wildfires,” particularly with respect to risk assessment.

The seven-member committee, usually known by its acronym CASAC and rounded out with an auxiliary panel of 15 other experts, is charged with providing EPA with independent advice during periodic reviews of the ambient air standards for soot and five other pollutants.

Soot is more technically known as fine particulate matter, or PM2.5, because individual specks are no more than 2.5 microns in diameter, one-thirtieth the width of a human hair. Direct or indirect sources are both natural and human-made, including coal-fired power plant smokestacks, car and truck exhaust, wildfires and construction activities.

Because those particles can reach deep into the lungs, sometimes even reaching the bloodstream, soot is regarded as a particularly harmful pollutant. Among the health effects: worsened asthma, some types of heart attacks and a higher risk of early death for people already suffering from respiratory and cardiovascular disease.

EPA’s current annual primary exposure standard was set in 2012 at 12 micrograms per cubic meter of air; the daily primary threshold, dating back to 2006, is 35 micrograms. The majority of the committee, made up mostly of university-based researchers, is recommending a cut in the annual limit to somewhere been 8 and 10 micrograms, and tightening the daily limit to between 25 and 30 micrograms. In a draft report released last fall, EPA career employees similarly concluded that the evidence warranted a reduction in the annual standard but found the current daily limit to be adequate.

But today’s unanimous vote to forward the recommendations masked Boylan’s internal dissents from both of the majority’s findings. While agreeing that a stricter annual threshold is needed, Boylan believes that it should be in the range of 10-11 micrograms per cubic meter of air, while he seconded the agency’s career staff’s view that the daily limit does not need to be strengthened.

Regan had launched the review last June after concluding that the current standards — left in place following a fast-track Trump administration assessment — were likely inadequate. Driving the push for stronger limits is mounting evidence — including studies of millions of Medicare recipients by Harvard University researchers — that stronger limits would save lives, particularly among people of color.

In an overview of 47 urban areas released as part of the draft report, for example, EPA linked as many as 45,100 premature deaths in 2015 to long-term soot exposure at levels “just meeting” the current air quality standards, with communities of color facing the highest average concentrations. Accordingly, Black Americans stand to benefit the most in terms of the reduced risk resulting from any cut to the annual standard, the overview found.

But because of the variety of soot sources, any tightening of the standards can have significant consequences for industry permitting and compliance, although regulators maintain that the health gains far outweigh the compliance costs. When EPA tightened the annual standard in 2012, for example, the agency forecast that the change would yield at least $4 billion in health benefits in return for a maximum $350 million price tag for industry (Greenwire, Dec. 14, 2012).

Under the Clean Air Act, the primary ambient air standards for soot and other pollutants are intended to safeguard human health. But at an informal public hearing last Friday, EPA also faced criticism for failing to pay attention to secondary soot standards aimed at protecting vegetation, visibility and other environmental features (Greenwire, Feb. 25).

Among those endorsing the proposed tightening of the primary soot standards was Daniel Orozco, a senior analyst with the National Parks Conservation Association, who said EPA didn’t “fully consider the science” around soot’s harmful effects to ecosystems and visibility. While many national parks are covered by a separate haze reduction program, stronger secondary standards “will go a significant way toward assisting these places in achieving” air quality goals, he said.

But Daren Bakst, a senior research fellow at the Heritage Foundation, a conservative think tank, questioned why EPA was proceeding with the new review at all a little more than a year after the Trump administration had found no need for change. He also alluded to Regan’s decision last year to reconstitute the CASAC after ousting all members in what was described as an effort to break with contested Trump-era appointment policies.

“This shocking move, made before the EPA’s decision to review the standards, certainly gives the impression, right or wrong, that the administrator wants to hear only from those who will support President Biden’s agenda,” said Bakst, who previously backed other Trump administration environmental moves (Greenwire, Dec. 8, 2020).

The CASAC dismissals, as well as a similar wholesale shakeup of another EPA advisory panel, are the target of a lawsuit brought by two former members who were among those fired. Last month, a federal judge denied their bid for an injunction that would have blocked the committee from holding the round of meetings that ended today (Greenwire, Feb. 17).