Race/ethnicity, residential segregation, and exposure to ambient air pollution: the Multi-Ethnic Study of Atherosclerosis (MESA).

OBJECTIVES: We described the associations of ambient air pollution exposure with race/ethnicity and racial residential segregation.

METHODS: We studied 5921 White, Black, Hispanic, and Chinese adults across 6 US cities between 2000 and 2002. Household-level fine particulate matter (PM2.5) and nitrogen oxides (NOX) were estimated for 2000. Neighborhood racial composition and residential segregation were estimated using US census tract data for 2000.

RESULTS: Participants in neighborhoods with more than 60% Hispanic populations were exposed to 8% higher PM2.5 and 31% higher NOX concentrations compared with those in neighborhoods with less than 25% Hispanic populations. Participants in neighborhoods with more than 60% White populations were exposed to 5% lower PM2.5 and 18% lower NOX concentrations compared with those in neighborhoods with less than 25% of the population identifying as White. Neighborhoods with Whites underrepresented or with Hispanics overrepresented were exposed to higher PM2.5 and NOX concentrations. No differences were observed for other racial/ethnic groups.

CONCLUSIONS: Living in majority White neighborhoods was associated with lower air pollution exposures, and living in majority Hispanic neighborhoods was associated with higher air pollution exposures. This new information highlighted the importance of measuring neighborhood-level segregation in the environmental justice literature.