South SFV Today

A new study by Stanford Medicine researchers and collaborators has found significant racial disparities in deaths related to air pollution. The research, which accounts for both exposure to air pollution and susceptibility to its harms, reveals that Black Americans are more likely to die from causes related to air pollution compared with other racial and ethnic groups.

“We see differences across all factors that we examine, such as education, geography and social vulnerability, but what is striking is that the differences between racial-ethnic groups — partially due to our methodology — are substantially larger than for all of these other factors,” said Pascal Geldsetzer, MD, PhD, assistant professor of medicine and lead author of the study published July 1 in Nature Medicine.

The findings indicate that air pollution significantly contributes to health inequities among different demographic groups. Researchers suggest that reducing air pollution could be a powerful means to address these disparities.

Air quality in the U.S. has improved over recent decades due to regulations like the Clean Air Act. However, not all communities have benefited equally from these improvements. Fine particulate matter (PM2.5), particles less than 2.5 micrometers in diameter that can enter the bloodstream and affect vital organs, remains a major concern.

“It’s very well recognized that PM2.5 is the biggest environmental killer globally,” said Tarik Benmarhnia, PhD, associate professor at the University of California, San Diego’s Scripps Institution of Oceanography and senior author of the study.

Exposure to PM2.5 can exacerbate conditions like asthma and chronic obstructive pulmonary disease in the short term and contribute to heart disease, dementia, stroke, and cancer in the long term.

Despite overall reductions in PM2.5 levels since 1990, some groups remain disproportionately affected. The study found higher rates of PM2.5-attributable mortality among people with less education; those living in large metropolitan areas; and those who were more socially vulnerable due to housing or poverty issues.

The most significant disparities were observed when data was sorted by race and ethnicity. In 1990, Black Americans had a PM2.5-attributable mortality rate of roughly 350 deaths per 100,000 people compared with less than 100 deaths per 100,000 people for other races. By 2016, this rate had declined but remained highest among Black Americans at around 50 deaths per 100,000 people.

In nearly all counties studied (96.6%), Black Americans had the highest PM2.5-attributable mortality rates.

Race was identified as the most influential factor determining mortality risk from air pollution due to increased exposure levels combined with amplifying factors such as poverty and lack of access to healthcare.

“Racism is an upstream driver of all these components of social inequality,” Benmarhnia noted.

The researchers emphasized that reducing air pollution could help mitigate health disparities because it is an actionable area where improvements can be made relatively quickly.

“We want to emphasize how air pollution is a very good way to reduce health disparities because it’s actionable,” Benmarhnia said. “We know we can do something about air pollution.”

The study received funding from the National Institutes of Health (grants R01AI127250, R01HD104835 and R01CA228147), the Robert Woods Johnson Foundation and the California Environmental Protection Agency.