Even small increases in exposure to air pollution makes people more vulnerable to covid-19, according to a new study published in Science Advances.
The research, conducted by Harvard researchers, analyzed air emissions data from more than 3,000 counties across the U.S. that are home to 98% of the country’s population. The analysis focused specifically on bits of particulate matter known as PM2.5. They then compared these findings with data on covid-19 morbidity rates from the same counties. This correlation remained even after the scientists adjusted their results for 20 other county-wide factors, including average age, race, reported smoking habits, and degrees of social distancing measures taken in the region.
Their findings suggest that long-term exposure to every additional microgram of PM2.5 per 35.3 cubic feet (1 cubic meter) of air increases covid-19 mortality rate by 11%. In an editorial published alongside the study, other researchers noted that this isn’t totally surprising, since even short-term PM2.5 exposure has been linked to increased risk of of acute lower respiratory infections and hospitalizations for the flu. Still, 1 microgram is a tiny amount of air pollution, so the findings are pretty stunning.
In addition to air pollution exposure, the data indicated other risk factors associated with an increases in an area’s covid-19 death rate, including a lower median household income and a higher percentage of Black residents.
The report is the latest in a slew of research demonstrating the link between dirty air and covid-19 susceptibility. Another study published in late October in Cardiovascular Research found that long-term exposure to air pollution contributed 15% to global covid-19 mortality.
The editorial said that the latest findings cannot determine who exactly is most at risk of perishing at the virus’ hands because they only had data on outside factors like age and smoking habits at the area level, not the individual level.
“The ideal way to address questions about how PM2.5 pollution might influence the course of the pandemic would involve the study of detailed health datasets for very large numbers of people from all walks of life and locations,” the editorial authors who were not involved in the study wrote. However, they note that the newness of the illness makes this data impossible to obtain.
Though the study is limited by the confines of the pandemic, these findings can still help inform policy decisions about covid-19. It’s more evidence that we need more resources to help polluted, impoverished regions handle the pandemic’s impacts. And of course, it’s also more evidence that we need to get a handle on air pollution across the country.