An extensive study of thousands of COVID-19 patients in Ontario hospitals has found links between the severity of their infections and the levels of common air pollutants they experience.
Chen Chen, an epidemiologist at the University of California, says the study suggests that the more long-term pollution people are exposed to, the worse a COVID-19 infection hits them.
The study has been published in the Canadian Medical Association Journal.
The study looked at more than 150,000 COVID-19 cases in Ontario patients and correlated their outcomes with levels of fine particles, ozone and nitrogen dioxide – the three components of smog.
Chen says the research shows that more severe reactions to the virus were associated with higher levels of long-term exposure to the contaminants.
She says it adds to the growing body of evidence that air pollution is what she calls a "silent killer."