African-Americans comprise a disproportionate share of COVID-19 illness and mortalities, and emerging data regarding the potential effect of air pollution exposure and COVID-19 severity may explain why. The study, conducted at Harvard and not yet peer-reviewed, correlated PM2.5 (air pollutant particulate matter less than 2.5 micrometers in diameter) exposure with COVID-19 mortality in the United States; for every 0.001 mg increase in PM2.5 per cubic meter, COVID-19 deaths increased by 15%:
“If you’re getting COVID, and you have been breathing polluted air, it’s really putting gasoline on a fire,” said Francesca Dominici, a Harvard biostatistics professor and the study’s senior author.African-Americans are more likely to live in areas of the United States with worse air pollution. Air pollution exposure is linked to a myriad of health conditions, including cardiovascular disease, pneumonia, asthma, urinary tract infections, Parkinson's disease, diabetes, and sepsis, even when controlling for other environmental and socioeconomic factors. Even short-term exposure to PM2.5 can have significant health effects. It's possible that the correlation between particulate matter pollution and COVID-19 merely reflects the increased prevalence of these underlying health conditions in African-Americans, but it's also plausible that both are insidiously working together to intensify the severity of COVID-19.
Air quality has dramatically improved in many places since shelter-in-place orders have gone into effect; I've certainly noticed the difference in the metropolitan area where I live. These improvements in air quality may even be helping to "flatten the curve" of COVID-19 transmission. Sustaining these improvements may be challenging once we all return to our prior routines, but given that air pollution contributes to over 100,000 deaths per year in the United States, perhaps this might be an opportunity to push back against efforts to deregulate environmental protections on air quality.
Physicians can and should advocate for improved air quality along with other environmental changes that can positively affect our patients' health. This 2017 AFP editorial and this 2016 ACP position statement both outline practical ways physicians can contribute to these efforts.