Study shows racial and ethnic minorities and low-income groups in U.S. experience higher levels of air pollution

According to a new study published in the journal Nature, Black, Asian, Hispanic, Latino, and low-income communities are exposed to higher levels of a dangerous air pollutant knows as PM2.5, compared to other populations in the United States.

The research was conducted at the Harvard T.H. Chan School of Public Health and led by Francesca Dominici, PhD, Harvard Chan School Professor of Biostatistics, Population and Data Science. Researchers studied demographic data from the U.S. Census Bureau and American Community Survey from 2000 to 2016. They combined demographic data with data on PM2.5 levels, gathered from satellite observations and atmospheric chemistry models analyzing all 32,000 U.S. zip code tabulations areas (ZCTA).

On average, from 2000 to 2016, researchers found that exposure to PM2.5 decreased from 12.6 micrograms per cubic meter of air (μg/m3) to 7.5 μg/m3, dropping below the recommended maximum exposure of PM2.5, 12 μg/m3. In addition, the percentage of the U.S. population exposed to PM2.5 levels greater than 12 μg/m3 dropped from 57.3 percent in 2000 to 4.5 percent in 2016. However, researchers also found that areas that were majority white or Native American consistently had lower levels of PM2.5 than majority Black, Asian, Hispanic, or Latino areas.

The study’s results showed that the more Black or Latino people living in a particular ZCTA, the greater the levels of PM2.5 exposure. In contrast, the study showed decreased levels of PM2.5 in ZCTAs with high white and Native American population densities. In addition, researchers found areas with lower income groups had increased exposure to PM2.5 compared to areas with higher income levels. The study also found relative disparities among racial and ethnic group exposure to PM2.5 had increased from 2000 to 2016.

These findings suggest that although the U.S. has decreased overall PM2.5 levels, disparities in PM2.5 exposure remain between ethnic, racial, and income groups, highlighting the need for more targeted air-pollution reduction.