Multiscale Vehicle Traffic Air Pollutant Exposure and Equity Analysis in the United States using a Novel Emissions Exposure Surrogate

This study develops a refined surrogate, “emission density,” to access exposure to hazardous air pollutants from on-road vehicle traffic in communities across the U.S. that balances spatial precision and computational burden. Our results show that people of color and lower-income people are disproportionately exposed to higher levels of traffic emissions almost everywhere in the U.S. Specifically, 89% of U.S. counties exhibit significant associations between increased exposure to NOX and PM2.5 emissions and higher proportions of people of color and lower household incomes. On average, people of color experience twice as the exposure of White individuals, while low-income households are exposed to more than three times the exposure. Additionally, medium- and heavy-duty vehicles contribute disproportionately to emissions relative to traffic volume. Despite declines in vehicle emission rates, the growth in near-roadway populations, rising traffic volumes, and persistent inequities present ongoing public health and environmental justice concerns. This analysis offers critical insights for identifying the most impacted communities and evaluating the effectiveness of potential policies at local, state, and national levels to reduce exposure.