Common air pollutants such tiny particulate matter and ground-level ozone are linked to worse outcomes following COVID-19 infection, including admission to the intensive care unit (ICU), a study finds.
The research, which was published in the Canadian Medical Association Journal on Tuesday, looked at data from 151,105 patients aged 20 and over in Ontario, Canada, who had confirmed SARS-CoV-2 infection in 2020 and were not in a long-term care facility.
Before the pandemic, the researchers' calculated previous exposure to three prevalent air pollutants: fine particulate matter (PM2.5), nitrogen dioxide (NO2), and ground-level ozone (GLO) (O3). Date of diagnosis, sex, age, being part of an outbreak, essential worker status, neighbourhood socioeconomic status, health care access, including previous influenza vaccine history, previous outpatient visits, and other factors were all taken into account.
COVID-19-related hospital admissions, ICU admissions, and mortality were found to be 8,630, 1,912, and 2,137, respectively, in the study. According to the researchers, the median periods between first diagnosis and hospital admission, ICU admission, and death were 5 days, 8 days, and 15 days, respectively.
"After we adjusted for individual and contextual confounding factors, we found that people with SARS-CoV-2 infection who lived in areas of Ontario with higher levels of common air pollutants were at an increased risk of being admitted to the ICU, even when the air pollution level was relatively low," said Hong Chen of Health Canada. The researchers also found that prolonged exposure to PM2.5 and O3 increased the probability of hospitalisation and that chronic exposure to O3 increased the chance of death from COVID-19.