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Air pollution levels in American Indian communities in the Great Plains and Southwest: The Strong Heart Study

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  • Overview
Differences in environmental exposures—particularly to ambient air pollution—have been consistently documented across communities in the United States (U.S.). However, relatively few studies on air pollution have focused on American Indians. In this paper, we combine demographic data from Phase IV (2001–2003) and Phase V (2006–2009) of the Strong Heart Study—the largest ongoing longitudinal epidemiologic cohort study of cardiovascular disease in American Indians—and 1 km2 modeled PM2.5 data in the Northern Plains, Southern Plains, and Southwestern United States. We analyzed data at the U.S. ZIP code level to estimate 30-day and annual residential exposures of participants to PM2.5 and assess for regional, temporal, and seasonal variations in PM2.5 exposure. We found significantly higher mean 30-day and annual PM2.5 concentrations among participants in the Southwest and Southern Plains (>7.4 μg/m3 and >7.6 μg/m3, respectively) than in the Northern Plains (<6.6 μg/m3 and <6.2 μg/m3, respectively). We observed heterogeneity in participants' mean 30-day and annual PM2.5 exposure within and across regions. Furthermore, seasonal differences in ambient PM2.5 concentrations among participants varied by region; in the Northern Plains, we generally observed higher mean 30-day PM2.5 exposure levels in the summertime and lower levels in the wintertime, whereas levels remained relatively constant in the Southern Plains and Southwest. These findings offer essential baseline data to advance accurate and equitable exposure assessment across tribal communities in the Northern Plains, Southern Plains, and Southwest regions.

Impact/Purpose

Air pollution and its impacts affect people differently, based on sociodemographic and health characteristics. As the Agency prioritizes environmental conditions, research on differential impacts of major air pollutants, including fine particulate matter (PM5) on different populations are necessary. This research demonstrates exposure to air pollution among American Indians, a heavily burdened and understudied population. We estimated 30-day and 1-year ambient PM2.5 concentrations among American Indian participants of the Strong Heart Study located in North and South Dakota, Oklahoma, and Arizona using a hybrid model. American Indian participants of the Strong Heart Study in North and South Dakota had the lowest 30-day PM2.5 exposures (5.5 μg/m3), followed by Oklahoma (9.1 μg/m3), and Arizona (9.2 μg/m3). We did not detect a seasonal effect on PM2.5 exposure in AZ; however, PM2.5 in the wintertime was slightly higher in OK and substantially higher in ND and SD. Results for annual PM2.5 exposures were similar. PM2.5 exposures were below NAAQS standards for Strong Heart Study participants. This study helps to further understand environmental disparities among American Indians.

Citation

Brooks, J., A. Weaver, B. Zou, M. Li, J. Reese, C. Ward-Caviness, J. Yracheta, K. Malloy, Y. Zhang, N. Franceschini, G. Corbie-Smith, G. Currin, AND A. Navas-Acien. Air pollution levels in American Indian communities in the Great Plains and Southwest: The Strong Heart Study. Turkish National Committee for Air Pollution Research and Control, Izmir, TURKEY, 17:1, (2026).
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Last updated on September 04, 2026
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