As counter to the Obama Administration’s purported “war on coal,” President Trump and EPA Administrator Scott Pruitt have undertaken a war for coal which, among other things, trends against the economics of energy supply. Attacking climate science and climate policy is the most visible front of this war, but it leaves open a vulnerability: in addition to emitting carbon dioxide, pollution from coal-fired power plants also happens to have negative health impacts that can kill people. We know this because of a growing body of scientific research that finds strong links between levels of fine particulate matter, or “PM-2.5,” and premature mortality. This is the science that is the target of EPA’s “secret science” proposal and the collateral damage will be public health and decent governance.
PM-2.5 is a dangerous pollutant because unlike coarse, not-so-fine particulate matter, it is smaller and can penetrate into the lungs of people more deeply, where it lodges more securely and can cause lung cancer and other cardiopulmonary diseases. The insidious health effects of PM-2.5 wouldn’t be known without careful scientific study. The most influential and rigorous example is the decades-long Harvard Six Cities Study, which started recruiting test subjects in 1982, and has been carefully tracking their health since.
Participants were selected from six diverse cities, chosen for their representativeness of the general population and their levels of PM-2.5 pollution. The first of a series of studies was released in 1993, and found unambiguously that PM-2.5 was, in fact, significantly increasing mortality rates. Numerous subsequent studies have confirmed and even strengthened this link. PM-2.5 kills millions of people worldwide, and tens of thousands in the United States. PM-2.5 isn’t necessarily the only cause, but might be pushing over the edge people that already had health problems.
Of course, correlation does not prove causation. What’s to say that these research subjects didn’t die from some other cause? Such studies, known as “panel studies,” are critical to research because they carefully track individuals over time, rather than trying to draw inferences from what happens to a broad cross-section of people. Finding a link between premature death and PM-2.5 requires this kind of tracking, gathering data on each person, their eating and exercise habits, their weight, age, ethnicity, income, occupation, whether or not they are a smoker, whether or not they had existing cardiopulmonary problems, and other factors.
This, the researchers could only do by administering a 44-question survey, which could only be administered by guaranteeing confidentiality. The researchers were entrusted with people’s data, bearing a responsibility to keep it “secret.”
Despite the secrecy of individuals’ data, the Harvard Six Cities Study and its progeny are, in fact, among the most transparent and thoroughly vetted studies in the history of health science. Because the implications were so great and so shocking—tens of thousands of people were dying due to pollution from coal-fired power plants—the EPA and the United States Congress commissioned a “re-analysis” of the study, by the Health Effects Institute, a health research organization that receives half its funding from the EPA and half from industry. A team of HEI researchers performed its own analysis on the Harvard data, and the verdict was clear: the Harvard study was sound. Both the HEI and the Harvard group have conducted follow-up studies, incorporating new data (more results from more of the original 1982 subjects). In an HEI 154-page follow-up report, the finding was the same, only the effects of PM-2.5 were more pronounced.
The number of premature deaths from PM-2.5 has sometimes gone down in follow-up studies, but not because the original study was flawed; rather, it was because this research led to regulation that led to lower PM-2.5 pollution, which in turn led to a smaller number of deaths. Reducing the number of premature deaths by using the best scientific information should be lauded as the success of science over intuitive toxicology. There is a reason why this study was undertaken in the United States: its unique research capacity, and the erstwhile commitment of the EPA to using evidence to craft policy for the good of the American people.
Eliminating EPA access to the Six Cities data, or any study that uses it, will hamstring the EPA’s ability to further protect public health. Ensuring transparency is an important part of Congressional and public oversight of the agency. But the details of each participant’s life need not be available for internet download for the study’s conclusions to be trustworthy, as repeated studies have shown the Harvard study to be. The health impacts of PM-2.5 will be there whether we look for them, understand them, or act on them. We should do all three.