All-Cause NO₂-Attributable Mortality Burden and Associated Racial and Ethnic Disparities in the United States

Nitrogen dioxide (NO₂) is a regulated pollutant that is associated with numerous health impacts. Recent advances in epidemiology indicate high confidence linking NO₂ exposure with increased mortality, an association that recent studies suggest persists even at concentrations below regulatory thresholds. While large disparities in NO₂ exposure among population subgroups have been reported, U.S. NO₂-attributable mortality rates and their disparities remain unquantified. Here we provide the first estimate of NO₂-attributable all-cause mortality across the contiguous U.S. (CONUS) at the census tract-level. We leverage fine-scale, satellite-informed, land use regression model NO₂ concentrations and census tract-level baseline mortality data to characterize the associated disparities among different racial/ethnic subgroups. Across CONUS, we estimate that the NO₂-attributable all-cause mortality is ∼170,850 (95% confidence interval: 43,970, 251,330) premature deaths yr⁻¹ with large variability across census tracts and within individual cities. Additionally, we find that higher NO₂ concentrations and underlying susceptibilities for predominately Black communities lead to NO₂-attributable mortality rates that are ∼47% higher compared to CONUS-wide average rates. Our results highlight the substantial U.S. NO₂ mortality burden, particularly in marginalized communities, and motivate adoption of more stringent standards to protect public health.