This week, the EPA announced that its Clean Air Scientific Advisory Committee (CASAC) alone would be reviewing upcoming ozone and particulate matter reviews. On October 10, the EPA nixed its ozone and particulate matter review panels—breaking with EPA’s use of expert science advisers for ambient air quality decisions since the 1970s and consistent with this administration’s trend of abandoning science advice. That same day, the EPA replaced the independent scientists on CASAC, leaving a committee of mostly state and local regulators. On December 12, the EPA will bring together the new CASAC for the first time in person to discuss the state of the science on particulate pollution. Will the EPA be able to assess the science and make science-based decisions to protect public health? Here’s what to watch for.
A history of independent science advice
Using science to set ambient air pollution standards has worked remarkably well in the US. Under both Democratic and Republican administrations, our nation has been able to follow a science-based process to set air pollution standards that protect public health. Not to say there has never been political interference (see examples under both George W. Bush and Barack Obama), but the process by which EPA gets science advice on pollution standards has remained intact, even under tremendous pressure from industries and political actors to compromise the process.
Here’s how it works (at least up until now):
For major ambient air pollutants, the EPA assesses the state of the science on a pollutant and its health effects every five years or so, gathering all relevant peer-reviewed science into what’s called the Integrated Science Assessment (ISA). The exhaustively comprehensive ISA looks at all the relevant scientific literature that sheds light on the relationship between a pollutant and human health and welfare. (Fun Fact: The current particulate matter ISA includes extensive discussion of my own academic research on air pollution measurement and exposure error.)
The scientific teeth of the ISA are found in its causality findings—these summarize the weight of the evidence for linkages between the pollutant and different health effects. They range from “not causal” to “inadequate evidence” to “likely causal” to “causal.” It is important to note there is tremendous scientific backing behind each of these statements. A finding that the association between particulate matter exposure and mortality is causal, for example, is backed by science from multiple lines of evidence—epidemiologic studies, toxicology studies, controlled human exposure studies, and biological plausibility knowledge. The robust causal determination framework used by EPA has been vetted and endorsed broadly by experts in the scientific community. These causal findings inform EPA decisionmakers on how to best protect people from harmful pollutants.
To ensure that EPA scientists get the science right, they get help from the independent scientists on CASAC. In addition, since the 1970s the agency has relied on pollutant review panels to get input from experts on specific pollutants. CASAC, too of course, is comprised of air pollution experts, but it is only seven people. It is not possible for this small committee to capture the breadth and depth of the ISA and properly assess all aspects of the science. For example, to assess particulate pollution’s health impact, you’d want experts in epidemiology, toxicology, exposure assessment, instrumentation, modeling, and a host of other specialties. As a result, the EPA has always relied on larger groups of experts like the particulate matter review panel to peer-review its ISA and ensure it gets the science right.
An ill-equipped EPA
But now, EPA is going through the PM and ozone review processes with far less scientific expertise. The Trump administration dismissed the particulate matter review panel entirely, failed to constitute an ozone panel, and removed the independent scientists serving on CASAC. Now the agency is left with a seven-member committee of mostly air pollution regulators. This leaves very little subject matter expertise on air pollutant science and health.
In one striking example, our scientific understanding of particulate matter’s health effects is based in no small part on epidemiologic studies. And yet, not a single epidemiologist will be at the table when EPA assesses the ISA. (The EPA even admits this glaring omission in its recent announcement.) To say that the EPA is ill-equipped to have a scientific discussion on particulate matter in December is an understatement.
This lack of preparedness is exacerbated by the remarkable speed at which EPA is moving. The agency plans to set new ozone and PM standards by 2020—markedly faster than reviews have typically happened given the necessary steps required to gather scientific information, incorporate reviews from CASAC and the pollutant review panels, solicit public impact, analyze policy implications before making a policy decision. To meet this arbitrary deadline, EPA intends to streamline the process, combining analyses that used to be separate documents and likely cutting down on the number of meetings and draft documents. Such measures are almost certain to mean less public input and less scientific assessment feeding into the process.
How should we protect people from particulate matter?
So how should the administration protect people from the harms of particulate matter? The science suggests the EPA should be doing more. The draft ISA finds causal links between PM2.5 (that is, particulate matter less than 2.5 micrometers) and premature death and cardiovascular disease, and likely causal relationships between particulate matter and respiratory and nervous system effects and cancer. The scientific assessment also finds a likely causal link between ultrafine particles (PM less than 0.1 micrometers) and nervous system effects. This is the draft—prior to scientific review and public input—so the linkages are subject to change. But if these scientific findings hold, we should expect EPA to take action, in order to protect public health with an adequate margin of safety—as the Clean Air Act requires. Historically, when a pollutant is linked to a serious health impact, a standard is set to curb pollution. These linkages to health impacts suggest that EPA could consider tightening the PM2.5 standard in order to protect public health and that the agency could potentially propose a new standard for ultrafine particles. Historically, these are the kinds of considerations that CASAC and the PM review panel would vigorously debate at public meetings and calls, with opportunities for public input. But it is difficult now to see how the agency could do the same this time.
A need for science advice
Will this EPA take the further actions required to protect people from these health impacts? One thing is for sure, they are likely to get less science-based input on the decision. With a weakened CASAC and no pollutant review panels, EPA won’t get the direct and robust feedback it needs from the scientific community. Without that scientific input, it is easier for the administration to make a decision that’s politically convenient rather than scientifically backed.
To compensate for the lack of science advice formally being provided to the EPA, it will be especially important that the EPA hear from scientific experts at the December meeting on PM and the November 29 CASAC call to discuss the ozone review process. It is also crucial for the EPA to hear from the public at these meetings because the compressed timeline will mean fewer meetings and thus fewer opportunities for the public to provide comment. Both air pollution experts and members of the public can (and should!) provide comment for the ozone call (November 29) and PM in-person meeting (comments in writing by December 11) and in person (sign up by Dec 5) at the meeting in Washington DC December 12-13. Join me there. I’ll be asking the EPA to listen to the scientists and you can too.
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