Several common air pollutants are linked to more severe outcomes following a coronavirus infection, a new study has found. 

Individuals who lived in areas of Ontario, Canada with higher levels of three common air pollutants — fine particulate matter, nitrogen dioxide and ground-level ozone — were at increased risk of being admitted to the intensive care unit, according to the authors, who published their findings on Tuesday in the Canadian Medical Association Journal. 

Chronic exposure to ozone specifically carried an elevated risk of death from COVID-19, the scientists determined. 

To draw these conclusions, researchers from the Canadian government’s Health Canada analyzed data on all 151,105 people ages 20 years and older who had confirmed coronavirus infections in 2020 in Ontario. 

Information about fine particulate matter, nitrogen dioxide and ground-level ozone was readily available to the researchers, as these substances are all regularly monitored by the Canadian government, the authors noted. 

These pollutants are emitted from a variety of different sources, including fuel combustion and reactions of volatile organic compounds or other chemicals. 

The scientists calculated each infected individual’s long-term exposure to the three air pollutants based on their residence from 2015-2019, according to the study. 

The authors excluded infected individuals living in long-term care facilities and adjusted for date of diagnosis, sex, age, essential worker status, socioeconomics, healthcare access and other factors. 

Long-term exposure to air pollution, the authors explained, could increase the risk of developing severe COVID-19 by several different mechanisms. For example, air pollutants can reduce immune responses and antimicrobial activities in the lungs, thereby boosting viral loads, according to the authors. 

These substances can also cause chronic inflammation and the over expression of a specific receptor protein that enables the entry of coronavirus into human cells, the researchers added. 

“Given the ongoing pandemic, our findings that underscore the link between chronic exposure to air pollution and more severe COVID-19 could have important implications for public health and health systems,” the authors stated.

Air pollution linked to more severe COVID-19: study | The Hill