Harvard researchers publicly walked back Monday a key finding in a highly touted but hotly contested paper linking air pollution exposure to deaths from the novel coronavirus, slashing the estimated mortality rate in half.
The preliminary study by researchers at the Harvard T.H. Chan School of Public Health made a splash when the results were announced April 7 in The New York Times, prompting alarm on the left as Democrats sought to connect COVID-19 deaths to the Trump administration’s regulatory pushback.
A few weeks later, however, its researchers quietly backtracked from their finding that people who live for decades in areas with slightly more particulate matter in the air are 15% more likely to die from the coronavirus, lowering the figure to 8%. The press release was revised Monday.
“This article was updated on May 4, 2020, based on an updated analysis from the researchers using data through April 22,” reads a footnote on the Harvard press release.
The revision came after weeks of criticism over the study’s modeling and analysis. Tony Cox, a University of Colorado Denver mathematics professor and chairman of the Environmental Protection Agency’s Clean Air Scientific Advisory Committee, said the model used to derive the 8% figure had “no basis in reality.”
“The model has not been validated and its assumptions are unrealistic,” said Mr. Cox, who heads the advanced analytics consulting firm Cox Associates. “In layman’s terms, it assumes an unrealistic effect of fine particulate matter on deaths, and then with that assumption built into the model, it uses data to estimate how big that unrealistic effect is. They’re making an assumption that has no basis in reality.”
JunkScience’s Steve Milloy said the Harvard paper is “not just junk science, it’s scientific fraud.”
“There is no biological data to support the notion that air quality in any way affects the outcome of coronavirus infection — and the researchers know it,” Mr. Milloy said.
The paper has been submitted for publication but has not yet been peer-reviewed, meaning its estimates could change again.
“I would expect that if they keep going and improve the analysis further, and start putting in some of the important confounders that they omitted, that their association will continue to get smaller,” Mr. Cox said.
Even so, the initial results have been trumpeted by Democrats as fresh evidence of the health risk posed by fossil fuels, given that the fine particulate air pollution, or PM2.5, examined in the study is generated “largely from fuel combustion from cars, refineries, and power plants,” according to the Harvard release.
Gina McCarthy, EPA administrator under then-President Barack Obama, and former New York City Mayor Michael R. Bloomberg cited the study in a Monday op-ed for his eponymous news outlet, “How Trump’s EPA is Making Covid-19 More Deadly.”
“A recent Harvard study shows that even a tiny increase in fine particulate matter air pollution — commonly known as ‘soot’ — increases death rates from Covid-19,” said the op-ed. “Hit the hardest are low-income communities and people of color, who are disproportionately exposed to pollution sources, such as highways and refineries.”
Despite that, they said, “the Trump administration has launched a series of attempts to make our air dirtier and harder to breathe.”
Eight Democratic senators fired off a letter to the EPA warning that its pushback on the Obama administration’s climate agenda could “potentially increase the COVID-19 death toll and hospitalizations,” while the Joseph R. Biden presidential campaign touted the study on a press call with The Washington Post.
House Democrats also have pointed to the paper’s findings, while a petition from the Sierra Club, Earthjustice and the Colorado Latino Forum calling for a halt to a major Interstate 70 highway project referred to the COVID-19 risks outlined in the paper.
“In fact, one recently published study by Harvard University found that even a slight increase in exposure to air pollution ‘leads to a large increase in COVID-19 death rate,’” said the petition to Gov. Jared Polis on ActionNetwork.
In a Friday letter, Rep. Andy Harris, Maryland Republican, asked the EPA and the Department of Health and Human Services to “undertake an assessment of the recent claims” in the Harvard study on a “causal association between long-term exposure to fine-particulate matter and the likelihood of dying of COVID-19.”
“Clearly, the widespread political and media attention to the pre-publication findings has the potential to significantly influence public perception and policy outcomes associated with the nation’s response to the COVID-19 pandemic,” Mr. Harris said in the letter.
The paper was led by a Harvard doctoral candidate, Xiao Wu, and its co-authors include Harvard biostatistics professor Francesca Dominici, who said the 15% figure was lowered in response to “more updated data plus a more comprehensive and rigorous adjustment for potential confounding factors.”
Ms. Dominici said the paper was upfront about the research’s limitations, pointing out that “[h]igh quality nationwide individual-level COVID-19 outcome data are unavailable at this time and for the foreseeable future, thus necessitating the use of an ecologic study design for these analyses.”
“The study used standard statistical approaches and it is fully reproducible (data and code are publicly available) and accounts for over 20 confounding variables and we have conducted over 68 sensitivity analyses to check the sensitivity of the results to the specification of the statistical model,” Ms. Dominici said in an email.
Mr. Cox argued that the study failed to control adequately for confounders such as the differences in crowding between rural and urban communities.
“They really didn’t look at the rural urban continuum, and it’s puzzling to me that they didn’t do so, because it’s very easily available information,” he said. “They didn’t include it. And in my opinion, that would be a very important variable to include.”
The EPA has moved to address the impact of factors such air pollution on COVID-19, a “rapid review” from the Scientific Advisory Board on the health and environmental impacts of the contagious virus that has killed 248,000 worldwide since emerging in December in Wuhan, China.