The Biden administration is poised to sign off on one of the longest-running and precedent-setting reviews of air quality standards in agency history — but its fate is clouded by incoming President-elect Donald Trump and pointed disagreements over its scientific underpinnings.
With a Dec. 10 deadline for EPA to wrap up work, the forthcoming regulations will likely mark a first-ever attempt to confront an enduring physical reality: That what’s pumped into the air via smokestacks and tailpipes doesn’t necessarily stay in the air.
Instead, pollutants like sulfur and nitrogen may waft to earth where they can acidify lakes and streams, trigger harmful algae blooms, and stunt tree growth.
EPA has struggled to confront the issue under a two-tier system that critics see as tilted against ecosystem protection in favor of public health safeguards.
The agency’s quest to now tackle atmospheric deposition’s baleful impacts has sparked a behind-the-scenes rift between its air and research offices, alongside an even sharper public split with an expert advisory panel, records obtained by POLITICO’s E&E News show.
Whatever the scope of the final standards, furthermore, more than a decade of work could be swiftly undone by a second Trump administration and the Republican-controlled Congress that takes office early next year.
“That is a concern, yes, that it would be rescinded,” said Georgia Murray, staff scientist at the Appalachian Mountain Club, which supports stronger limits for all three classes of pollutants covered by the update: sulfur oxides, nitrogen oxides (NOx) and fine particulate matter.
The outcome could be particularly consequential for estuaries like the Chesapeake Bay and National Park Service lands. Roughly 90 percent of the largest parks and wilderness areas, for example, are in “fair” or “poor” condition for nitrogen deposition, Park Service employees told EPA in written comments last year.
Similarly, airborne pollution continues to contribute “substantially” to nitrogen in the bay’s waters, according to estimates cited by EPA.
Even before the review is formally completed, Murray sees it as an opportunity lost. Republican-run states and business groups have meanwhile mobilized against any change to the status quo.
Internal divides
Launched in 2013, the assessment ranks as “the most complicated . . . we have undertaken, “ a senior EPA staffer said last year.
Under the Clean Air Act, the three pollutants are covered by National Ambient Air Quality Standards that EPA is supposed to revisit every five years in light of the latest research into their effects on human health and the environment.
Under the act’s framework, the bulk of the agency’s attention is typically devoted to the primary standards that are geared to protect human health. This review instead targets the secondary “public welfare” ecological safeguards for animals, crops and other vegetation.
Already, the assessment has consumed more than a decade. It took a federal lawsuit by the Center for Biological Diversity to prod EPA into agreeing to this month’s completion deadline.
On top of an unusual mashup of the standards for three pollutants, the review features an obstacle course of scientific complexities.
Among them: Emissions of NOx and sulfur dioxide (SO2), both of which are regulated under the act, have plummeted in recent decades. Not directly regulated, however, are releases of nitrogen-packed ammonia, which have stayed flat or slightly risen over the last 20 years, according to EPA.
How aggressively to respond has divided the two EPA branches that share responsibility for the reviews: the Office of Air Quality Planning and Standards and the Office of Research and Development.
The first has the lead in advancing potential regulatory changes; the latter rounds up and synthesizes the underlying body of scientific evidence. In a January memo, Mary Ross, the then-head of a research office advisory wing, voiced “significant” caveats over scientific vulnerabilities with the course taken by the air quality planning and standards office.
The current SO2 secondary standard, an artifact of the Nixon administration, is 500 parts per billion, based on a three-hour exposure average. Despite the plunge in emissions from power plants and other sources over the last half-century, research showed that a cut to a yearly limit of somewhere in the range of 2-4 ppb was needed to meet deposition targets, Ross wrote.
Ross, who has since retired, similarly questioned whether the long-standing thresholds for NOx and fine particles, technically known as PM2.5, were adequate.
But under an EPA proposal released in April, the SO2 standard would be overhauled to an annual yardstick in the range of 10-15 ppb. The limits on the other two pollutants would remain unchanged.
“The relationships between deposition and ambient air quality are stronger for SO2 than they are for the nitrogen oxides,” one person familiar with the matter said in an interview. “I think that’s a big factor in how the science was evaluated.”
In an August meeting with EPA Administrator Michael Regan to decide the agency’s ultimate course, the research office called for a SOx standard of 5 ppb, according to that person and another who were granted anonymity to discuss internal deliberations. Regan opted for 10 ppb, they said.
The final version of the rule, which has not yet been made public, could have since changed in the course of a routine evaluation by the White House regulations office. In a signal of the rule's imminent release, that evaluation ended Thursday, according to a government tracking website. An EPA spokesperson declined to comment on its contents.
The rulemaking exposed an even starker divide with the Clean Air Scientific Advisory Committee (CASAC), the panel charged with providing independent expertise to EPA during air quality standards reviews.
During two days of deliberations last year, committee members repeatedly noted a 2017 cutoff forscientific studies included in the review, meaning that the underlying body of research was then six years out of date.
In an arcane but crucially important wrinkle, they also questioned why EPA did not set a “deposition standard” for the three pollutants aimed at measuring how much ended up on the ground in place of the existing ambient air yardstick.
An EPA lawyer said the Clean Air Act doesn’t allow it. Some members were unconvinced.
“It just seems like you’re, you know, putting a round peg into a square hole,” Charles Driscoll, an environmental systems professor at Syracuse University, said at one point.
In a later report, most committee members floated a litany of caveats about EPA’s scientific approach and urged the agency to reconsider “its conclusion that a deposition-based secondary standard cannot be used to protect ecosystems from adverse effects.”
While recommending a change to the sulfur dioxide standard along the lines of what EPA eventually proposed, most members also agreed that tighter NOx and fine particle limits were warranted (see table).
But in the April draft rule, EPA stuck to its position, even while acknowledging that the practical impact of the proposed change to the SO2 standard would be nil.
“No additional emissions reductions are expected to be needed,” the agency said in an accompanying summary.
Opposition
Nonetheless, industry groups and some Republican-led states are opposed.
Even if the planned change to the SO2 limit doesn’t require any cuts, the implementation work would be “unnecessary, complex, and cumbersome,” Nancy Vehr, Wyoming’s state air chief, wrote in comments last year.
In feedback filed before the proposal’s release, a coalition made up of the U.S. Chamber of Commerce, the American Petroleum Institute and more than a dozen other groups highlighted the CASAC’s concerns in urging Regan to keep the status quo until a new review could be conducted.
“To do otherwise would be arbitrary and capricious,” coalition members wrote, using a boilerplate phrase that is often invoked in legal challenges. Because the standards are being finalized so close to the end of President Joe Biden’s term, they will also be easy prey for the Congressional Review Act, which allows lawmakers to scrap recently issued regulations by simple majority votes.
Representing the coalition is Joseph Stanko, a lawyer and lobbyist with the firm Hunton Andrews Kurth. He did not reply to an email last week asking about the group’s plans should EPA nonetheless lock in the proposed change to the SO2 standard.
The National Park Service, however, faulted EPA for “not fully considering CASAC recommendations, nor the credible scientific evidence" of the impact of nitrogen deposition on large parks and wilderness areas.
To the Appalachian Mountain Club’s Murray, “EPA is not willing to take whatever steps they should be taking to do the right thing with the science.
"They had an opportunity here,” she said in an interview, "and I don’t know when we’ll have that opportunity again.”
