In recent study Assessing whether long-term exposure to air pollution increases the severity of COVID-19 health outcomes, including death, is an important public health objective. Higher historical PM2.5 exposures are positively associated with higher county-level COVID-19 mortality rates after accounting for many area-level confounders in US. Epidemiological studies to estimate the association between long-term exposure to air pollution and COVID-19 hospitalization and death is a rapidly expanding area of research that is attracting attention around the world.
Several other studies also reveal that people who live in the most polluted areas are more likely to be infected by Covid-19 when exposed to the coronavirus, and then are more likely to suffer severe symptoms and die from the disease.
The strong correlation between air pollution and COVID-19 could be explained by the negative impact on the immune system. This was demonstrated for other diseases, and this is likely the case for COVID-19, too. The effect held not just for pollution levels at the time of the outbreak, but for levels over the previous years as well, indicating prior exposure had likely compromised people’s ability to fight off the illness.
Source: Wu et al .2020 Science Advances.