Posted on 7 November 2019 by , Guest Author

This is a re-post from the Union of Concerned Scientists by Gretchen Goldman

The Independent Particulate Matter Review Panel has released their consensus recommendations to the EPA administrator on the National Ambient Air Quality Standards for Particulate Matter. The group of 20 independent experts, that were disbanded by Administrator Wheeler last October and reconvened last week, hosted by the Union of Concerned Scientists, has now made clear that the current particulate pollution standards don’t protect public health and welfare.

The Clean Air Scientific Advisory Committee (CASAC)—the remaining seven-person committee that is providing science advice to the EPA on the particulate matter standards—meets this week to discuss their recommendations on whether the current standards are adequate. The letter from the Independent Panel will be the elephant in the room.

The elephant in the CASAC meeting

CASAC has already acknowledged that they don’t have the expertise to conduct the review but you know who does? The Independent Panel. The Panel has more than double the experts of CASAC, and importantly, it has multiple experts in each of the necessary scientific disciplines critical to ensure a comprehensive, robust review of the science supporting the standards.

As a result,we should watch whether or not CASAC aligns with the panel in their recommendations on the standards. If CASAC doesn’t decide this week to make a similar recommendation as the Independent Panel, they’ll have to explain why they disagreed with a larger, more experienced, and more diverse set of experts on the topic. In any event, the administrator will have access to both CASAC and the Independent Panel’s recommendations when he ultimately makes the decision of where to set particulate pollution standards. The panel’s recommendations should hold the administrator’s feet to the fire.

The fine particulate matter standards don’t protect public health

The standards of greatest interest are the primary PM2.5 standards. These are the standards for particulate matter less than 2.5 micrometers (fine particulate matter) that are designed to protect public health. The panel supported the preliminary conclusions of a Draft EPA Policy Assessment that the current standards aren’t requisite to protect public health.

The letter cited new and consistent epidemiological findings, supported by human and animal studies and other studies with natural experiments, as providing “clear and compelling scientific evidence” for tighter standards. Since the last particulate matter review, several new large-scale epidemiologic studies provide powerful evidence that particulate matter is causing adverse health outcomes (such as early death, heart attacks, and respiratory stress) at locations and during time periods with concentrations at or below the level of the current standards.

They write, “New and compelling evidence that health effects are occurring in areas that already meet or are well below the current standards.” Notably, this evidence cuts across different locations with different study populations, different study designs, and different statistical approaches.

Given the weight of the evidence from new studies across scientific disciplines and consistent with the decision-making process that EPA and its science advisers have used for many years, the panel recommends a particulate matter standard between 8 µg/m3 and 10 µg/m3 for the annual PM2.5 standard (compared to the current standard of 12 µg/m3) and between 25 µg/m3 and 30 µg/m3 for the 24-hour standard (compared to the current standard of 35 µg/m3) to protect public health. These ranges are tighter than those recommended in EPA’s Draft Policy Assessment.

Keeping the current fine particulate matter standards ignores the science

The Independent Panel rejected a potential argument for maintaining the current primary PM2.5 standards. The Draft Policy Assessment offered up an alternative rationale that might be used if the agency were to reject the draft assessment’s recommendation to strengthen the standards and maintain the current standards.  This alternative rationale explains that such a move would require the administrator to be arbitrarily selective in choosing which new studies to accept and which to toss and to disregard new epidemiologic evidence showing effects at lower levels.

The panel roundly rejected this justification, noting that, “Arguments offered in the draft Policy Assessment for retaining the current standards are not scientifically justified and are specious.” This is important because if the administrator fails to strengthen the standards, he’ll have to explain (both in court and in the court of public opinion) why he feels such a decision is science-based, as required under the Clean Air Act. And one proposed argument he could use has just been debunked by this expert Panel.

Otherwise, the EPA’s Draft Policy Assessment is scientifically sound

While the Independent Panel critiqued some details of the EPA’s Draft Policy Assessment, the panel agreed that the draft science and policy assessments were cohesive and robust and the panel commended the “good faith effort” involved in the policy assessment.  Specifically, the panel affirmed the use of EPA’s causality framework used in the Integrated Science Assessment they reviewed last year and the Policy Assessment’s new use of a hybrid modeling technique that allows for better assessment of risk from particulate matter exposure across the country especially in rural areas.

This diverges from what the seven-member CASAC has said and done around the EPA’s assessment of the science and policy. In December, they concluded that the agency’s draft science assessment was not a scientific document (it is) and CASAC Chair Dr. Tony Cox has been critical of the agency’s causality framework that has been developed with dozens of experts over more than a decade. This view is not shared by the scientific community, and now, not shared by the Independent Panel either.

Other particulate pollution standards also may need revamping

The Independent Panel decided other particulate standards were also inadequate. On PM10, particulate matter less than 10 micrometers, the panel recommended revising this standard downward given that the PM2.5 component would also be tightened and noted several research and monitoring areas that need further work. On the secondary standards, i.e. the standards designed to protect welfare effects, such as visibility, the panel concluded that the standards should be tightened in order to be more protective.

The panel condemns the EPA’s broken process

The Independent Panel’s deliberations, demands for further research, and unanswered questions highlight how broken the EPA process is. In a normal review cycle, the panel would have had the opportunity to talk with agency scientists directly. The EPA staff would then have considered their comments and revised the Integrated Science Assessment in response to the committee and panel’s suggestions. But because the administrator disbanded the panel and abbreviated the process, there was no opportunity for such dialogue and refinement of the agency’s science assessment before policy decisions were discussed. But alas, the panel had to make do with what was available to them and CASAC does too.

Fortunately for CASAC, an Independent Panel has already done their job, and they are free (and encouraged) to run with it, especially given the long list of ways that EPA Administrator Wheeler has damaged the ambient air pollution review process.

Listen and watch this week as CASAC discusses the same questions that the Independent Panel did last week. If CASAC comes to different conclusions than the larger, more experienced, and more diverse Independent Panel, we should ask why.

You can raise these questions yourself and demand that the administrator follow the panel’s recommendations, by providing written or oral public comments at a future CASAC meeting and commenting on the docket for the particulate matter rule-making. I’ll be providing public comments this afternoon urging CASAC to follow the advice of the Independent Panel and commenting on the EPA’s problematic process and drawing attention to that elephant in the room.