A number of studies have found a link between air pollution and increased covid-19 deaths, but it is not clear why. Both attack the lungs, but it could just be that more people live in polluted areas
Source:
https://www.newscientist.com/article/2241778-are-you-more-likely-to-die-of-covid-19-if-you-live-in-a-polluted-area/?utm_campaign=RSS%7CNSNS&utm_source=NSNS&utm_medium=RSS&utm_content=home