In a new study, scientists have investigated whether a relationship exists between air pollution and COVID severity. The researchers examined the levels of common air pollutants in Ontario, Canada, and the incidence of more serious cases of COVID-19 in people who resided in those areas.  The researchers analyzed data on all 151,105 people, aged 20 years and older, who tested positive for SARS-CoV-2 infection in 2020, and who did not live in a long-term care facility. They noted whether these people were hospitalized, admitted to an ICU or died...