Do fine particulate air pollution (PM) exposure and its attributable premature mortality differ for immigrants compared to those born in the United States?

In the United States (US), immigrants constitute a considerable and growing proportion of the general population. Compared to the US-born, immigrants have differential health risks, and it is unclear if environmental exposures contribute. In this work, we estimated disparities between immigrants and the US-born in fine particulate matter (PM) exposure and attributable premature mortality, including by region of origin and time since immigration. With PM estimates from a validated model at ~1 km spatial resolution and residential Census tract population data, we calculated the annual area-weighted average PM exposure for immigrants overall, the US-born, and immigrants separately by geographic region of origin and time since immigration. We then calculated the premature mortality attributed to PM for each population group, assessing disparities by immigrant status in PM exposure and attributable premature mortality in the US as a whole and in each US county to evevaluate spatial heterogeneity. Overall, immigrants were exposed to slightly higher PM (0.36 μg/m, 3.8%) than the US-born. This exposure difference translates to 2.11 more premature deaths attributable to PM per 100,000 in population for immigrants compared to the US-born in 2010. Immigrant - US-born disparities in PM and attributable premature mortality were more severe among immigrants originating from Asia, Africa, and Latin America than those from Europe, Oceania, and North America. Disparities between immigrant groups by time since immigration were comparatively small. Sensitivity analyses using 2000 data and a non-linear set of PM attributable mortality coefficients identified similar patterns. Our findings suggest that environmental exposure disparities, such as in PM, may contribute to immigrant health disparities in the US.