Researchers uncover flaws in studies linking COVID-19 mortality to air pollution

Two Canadian researchers studied the studies to see if the science was sound
  • Nov 02, 2020
  • 720 words
  • 3 minutes
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Almost as soon as the World Health Organization declared it a public health emergency of international concern, there was a rush in the scientific community to publish what we know about it. Like we’ve seen with the race to develop a vaccine, there was also a race to publish scientific papers on who is most vulnerable, how the virus spreads and now, with more data, what individual recovery looks like.

The first research articles were published in April 2020, just about a month after schools, workplaces and businesses in North America locked down in order to slow the spread of the virus A number of studies showed startling images of a visible reduction in air pollution, and correlated air pollution to an increased likelihood of mortality from COVID-19. Carleton University professor Paul Villeneuve, along with McGill University professor Mark Goldberg, had serious reservations about this research, so they studied the studies — nine of them — and found flaws, including the lack of peer-reviewed research, in the science. Canadian Geographic spoke with Villeneuve on the problems they uncovered and published about in Environmental Health Perspectives.

On the point behind his research

We see that there’s some serious flaws in the studies that have been done. We have serious concerns because people putting out this kind of work are sort of circumventing the peer review process. We don’t think it’s good science. Part of the challenge with COVID-19 is everyone’s rushing to understand what’s going on to try to come up with research that will improve public health. Obviously some research is better than others, but some have major issues. 

It all began from a paper that came out by a group at Harvard University around the end of April, that really struck us as missing the complexities. They came out with a very definitive number — if you increase air pollution by one unit, the risk of COVID death will increase by 15 per cent — and it was picked up by the New York Times and tweeted by Joe Biden and we said “Hold on a second.”

On the problems with the existing studies

Many of the studies we evaluated had major issues in terms of study design. They were looking at relationships between COVID-19 and air pollution and whether air pollution increased mortality — at a time when we weren’t even able to properly track deaths from COVID-19. This approach — measuring air pollution in a wide area and looking at mortality rates when the data is so poor — really raises concerns for us. For example, a few weeks ago there was a report of a motorcycle rally in South Dakota they thought accounted for 20 per cent of the cases in South Dakota. If you start looking at a correlation between air pollution and COVID deaths and you don’t account for things [like the motorcycle rally], that raises a lot of concerns in terms of the science. We agree it’s important to get research on COVID done quickly, but it has to be done right. 

On how those problems get worse 

There’s decades of air pollution research — really good research — that uses data collected at an individual level. But it’s a very politicized thing, like you have fossil fuel companies always trying to critique the science. So if you start putting out science of a lesser quality, it to some extent discredits the research that’s been done before. 

On what happens now that there’s misleading research out there

You’ve already seen a little bit [of pull back] with Harvard — they’ve released an updated copy of their paper that essentially cut the risk estimates in half. This is going to be a research question that’s going to be really hard to try to answer. There’s a lot of work being done to look at health trajectories over time and addressing how air pollution is a risk factor with COVID. We know it’s bad and we know it’s bad for so many other things, so what’s the benefit in knowing whether or not air pollution increases the [COVID-19] risk?


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