Disparities in Fine Particulate Matter Air Pollution Exposures at the US-Mexico Border: The Intersection of Race/Ethnicity and Older Age

Background: Environmental justice research in the United States (US) documents greater air pollution exposures for Hispanic/Latino vs. non-Hispanic White groups. This research has not focused on the intersection of race/ethnicity and older age nor short-term fine particular matter (PM2.5) exposures. We address those limitations in a study of US metropolitan area census tracts within 100 km of the US-Mexico border, a region with serious air quality issues. Methods: We use US Census American Community Survey data to construct sociodemographic variables and Environmental Protection Agency Downscaler data to construct long-term and short-term measures of PM2.5 exposure. Using multivariable generalized estimating equations, we test for differences in PM2.5 exposures between census tracts with higher vs. lower proportions of Hispanic/Latino older residents and non-Hispanic White older residents. Results: As the proportion of the Hispanic/Latino population ≥65 years of age increases, long-term and short-term PM2.5 exposures significantly increase. In contrast, as the proportion of the non-Hispanic White population ≥65 years of age increases, changes in long-term and short-term PM2.5 exposures are statistically non-significant. Conclusion: Findings illuminate how race/ethnicity and older age intersect in shaping PM2.5 exposure disparities and may inform efforts to mitigate air pollution exposures for older Hispanic/Latino people along the US-Mexico border.