Air Pollution in American Indian Versus Non–American Indian Communities, 2000–2018
Maggie Li, Markus Hilpert, Jeff Goldsmith, Jada L. Brooks, Jenni A. Shearston, Steven N. Chillrud, Tauqeer Ali, Jason G. Umans, Lyle G. Best, Joseph Yracheta, Aaron van Donkelaar, Randall V. Martin, Ana Navas‐Acién, Marianthi‐Anna Kioumourtzoglou
Abstract
Objectives. To compare fine particulate matter (PM 2.5 ) concentrations in American Indian (AI)-populated with those in non–AI-populated counties over time (2000–2018) in the contiguous United States. Methods. We used a multicriteria approach to classify counties as AI- or non--AI-populated. We ran linear mixed effects models to estimate the difference in countywide annual PM 2.5 concentrations from well-validated prediction models and monitoring sites (modeled and measured PM 2.5 , respectively) in AI- versus non–AI-populated counties. Results. On average, adjusted modeled PM 2.5 concentrations in AI-populated counties were 0.38 micrograms per cubic meter (95% confidence interval [CI] = 0.23, 0.54) lower than in non–AI-populated counties. However, this difference was not constant over time: in 2000, modeled concentrations in AI-populated counties were 1.46 micrograms per cubic meter (95% CI = 1.25, 1.68) lower, and by 2018, they were 0.66 micrograms per cubic meter (95% CI = 0.45, 0.87) higher. Over the study period, adjusted modeled PM 2.5 mean concentrations decreased by 2.13 micrograms per cubic meter in AI-populated counties versus 4.26 micrograms per cubic meter in non–AI-populated counties. Results were similar for measured PM 2.5 . Conclusions. This study highlights disparities in PM 2.5 trends between AI- and non–AI-populated counties over time, underscoring the need to strengthen air pollution regulations and prevention implementation in tribal territories and areas where AI populations live. (Am J Public Health. 2022;112(4): 615–623. https://doi.org/10.2105/AJPH.2021.306650 )