Population density and long-term exposure to air pollution influenced the speed at which COVID-19 spread through metropolitan areas, research finds.

During the “first wave” of COVID-19 in the United States, Rajan Chakrabarty, associate professor at Washington University in St. Louis, learned that African Americans made up 47% of the population in St. Louis, Missouri, but nearly three-quarters of COVID-19 cases.

That fact was from an article in the Boston Review, written by Jason Purnell, associate professor at Washington University’s Brown School. In it, Purnell notes that in St. Louis, African Americans were 12 times more likely than white residents to live in conditions with higher environmental risks, including poor air quality.

“It really motivated me to try to connect the dots between environmental injustice and the spread of COVID-19,” says Chakrabarty, who studies aerosol science at the McKelvey School of Engineering.

And as it turned out, aerosol science had a lot to say about the matter.


New research analyzes disparities in socioeconomic, environmental, and lung health factors to determine how they contributed to R0—the rapidity at which COVID-19 spread—through 12 metropolitan areas. Researchers found just two factors had an overwhelming influence on R0: population density and long-term exposure to air pollution.

Results appear in the journal Environmental Research Letters.

These two factors disproportionately affect communities with more minority residents.

The study, conducted in the Chakrabarty lab, used data from 12 metropolitan statistical areas (MSAs)—a census designation for groupings of counties made up of at least one “urbanized” area of 500,000 or more residents and the nearby areas that it’s tied to socially and economically.

Read the full article about environmental injustice and COVID-19's spread by Brandie Jefferson at Futurity.