Nearly all types of fine particulate air pollution (PM2.5) emission sources disproportionately affect people of color in the U.S., according to a new study conducted with data from 2014. In contrast, Whites experienced lower than average PM2.5 exposure in 2014 and were only disproportionately affected by one sector - coal electric generation. The authors note that people of color at every income level experienced disproportionately high exposure to PM2.5, suggesting these disparities are not simply tied to economic differences. While it has been known that U.S racial-ethnic minorities experience disproportionately high PM2.5 exposure, the relative contributions of different types of PM2.5 emission sources to this disparity have remained unknown. To investigate, Christopher Tessum and colleagues used an air quality model to estimate emissions from 5,434 PM2.5 source types listed in the 2014 EPA National Emissions Inventory. They grouped these source types into 14 source sectors and estimated how each sector affected five racial-ethnic groups in the U.S.: White (62% of population), Black (12%), Hispanic (17%), Asian (5%), and people of color (38%). The researchers found that the average PM2.5 exposure from all domestic anthropogenic sources in 2014 (not just a few primary culprits) was higher than average for people of color, Blacks, Hispanics, and Asians, but lower than average for Whites. This trend held true within individual states, within individual rural and urban areas, across incomes, and across exposure levels. Industry, light-duty gasoline vehicles, construction, and heavy-duty diesel vehicles were top emission source sectors for all of the non-White racial-ethnic groups studied. "Because of a legacy of racist housing policy and other factors, racial-ethnic exposure disparities have persisted even as overall exposure has decreased," the authors write. "Targeting locally important sources for mitigation could be one way to counter this persistence."
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