By Gretchen Goldman, Union of Concerned Scientists
Yesterday the EPA Clean Air Scientific Advisory Committee (CASAC) published a letter to Administrator Andrew Wheeler making recommendations on the agency’s approach to updating the ambient air pollution standard for particulate matter (PM). Chiefly, the science advisors have now acknowledged the group has inadequate expertise to conduct the review.
We are now in uncharted territory with the EPA in a tough position on both its PM and ozone pollution standard updates. Here are some key highlights from the letter and their implications.
CASAC asks that the particulate matter review panel be reinstated
“The CASAC recommends that the EPA reappoint the previous CASAC PM panel (or appoint a panel with similar expertise) as well as adding expertise…,” the committee members write in their consensus comments.
This is significant. Last October, then Acting Administrator Wheeler left CASAC high and dry by disbanding the particulate matter review panel—a group of experts that boosted the span of expertise CASAC and the EPA had access to in their review. The ~20-person pollutant review panels have for decades augmented CASAC’s expertise, helping to review the EPA’s science assessment on particulate matter and health and welfare effects. Since that time, I (and many, many, many others) have repeatedly called on the EPA to reinstate the panel.
In November, a letter from former ozone review panel members asked EPA leaders to reinstate the panel. In December, a letter from former PM panel members asked the same, and this group sent a second letter in March. A separate letter from former CASAC chairs asked for the panel as well. And an additional letter from 206 air pollution and public health experts asked that the panel be brought back. This is on top of many other public comments echoing similar concerns from scientists, scientific societies, and other experts in the air quality and health arena. Since November, CASAC members themselves have been saying they need more expertise, but the CASAC Chair had ignored these pleas, until now.
The fact that the committee now agrees it needs the panel is important. It sends a clear signal to the EPA administrator that the process for the review of the science informing the PM standard is inadequate. And the committee lays this out in no uncertain terms, declaring that, “Additional expertise is needed for [CASAC] to provide a thorough review of the [PM] National Ambient Air Quality Standards (NAAQS) documents. The breadth and diversity of evidence to be considered exceeds the expertise of the statutory CASAC members, or indeed of any seven individuals.” This is of course what we’ve been saying all along.
This acknowledgement of needed expertise puts agency leadership in a tough spot, given that just last week EPA Administrator Andrew Wheeler claimed that CASAC had a “good balance of expertise” despite disbanding of the panel. With an administrator who directly contradicts his agency’s science advisors, what’s the EPA to do? One thing is clear, this is an atypical process and it is sure to face legal challenges.
Chair Cox’s views on causality have been cast aside
CASAC Chair Dr. Tony Cox released a draft of this letter on March 7, which included eyebrow-raising language asking the EPA to throw away the time-tested and scientifically backed weight-of-the-evidence approach it has long used to assess the links between air pollutants and health effects. (More on Cox’s proposal and why its problematic in my Science magazine piece here).
In the final letter, this language on manipulative causality has thankfully been outsourced to Cox’s individual comments and a few places where it notes that “some CASAC members think…” This is considerably dampened from the draft letter where it appeared as a consensus recommendation for upending EPA’s weight-of-the-evidence process for developing a science-based PM standard.
The committee still cannot agree on scientific facts
The final letter has maintained language noting that CASAC could not come to agreement on the relationship between fine particle pollution (PM2.5 ) and early death, writing, “CASAC did not reach consensus on the causality determination of mortality from PM2.5 exposure.” This is striking given that the link between fine particulate matter exposure and early death is well-documented. It has been repeatedly demonstrated in different scientific studies, in different locations, and at different concentrations. Past CASACs and PM panels as well as some members of the divided current committee have acknowledged this relationship, and yet some members of the current committee are breaking with past science advisors and the greater scientific community.
CASAC criticizes the EPA’s science assessment
As in the draft letter, CASAC continue to be highly critical of the EPA’s science assessment, insisting on the document’s “Lack of comprehensive, systematic review.” (But who are they to judge if they’ve already admitted they aren’t the appropriate advisors?) To be clear, it is expected and desired that the committee would have suggestions and criticisms of the science assessment and would want to see a revised draft. (This, after all, is the hallmark of peer-review). However, the tone and extent of the criticism in this letter takes it up a notch.
By contrast, a group of 17 scientists from the disbanded panel, while detailing a number of revisions needed for improving the science assessment, stated, “We commend EPA staff for development of an excellent first draft of the ISA that provides comprehensive and systematic assessment of the available science relevant to understanding the health impacts of exposure to particulate matter.”
Given the committee’s own admission that the group is in inadequate to conduct the review, this does raise questions about whether the group is qualified to offer some of the detailed technical criticisms it does, such as on the adequacy of non-threshold models to estimate health associations at low concentrations and the need for study exclusion criteria.
What’s next on PM and ozone reviews?
The EPA will now decide what to do with this science advice. Will it revise the science assessment and send it back to CASAC or simply declare it does not need a second review? Will the PM panel be reconvened to review a second draft science assessment? What about the timeline for the PM standard update? We know the administration is working on an expedited schedule. Administrator Wheeler has made this clear.
And what about the ozone process? If CASAC has concluded it has inadequate expertise for the PM review, it is difficult to imagine they will feel qualified to conduct the upcoming ozone review, given it relies on a similar breadth of scientific disciplines. (The EPA is set to release the ozone science assessment this spring). EPA leadership failed to convene an ozone review panel last October so CASAC is again poised to review a massive scientific assessment with one hand tied behind its back. The agency could decide to plow forward in the PM standard update process, ignoring CASAC’s advice.
Regardless of what the agency does next, it is clear the process is broken, and its science advisors know it too.