A study from the Columbia University Mailman School of Public Health found that, while air pollution has been decreasing nationally, Native American communities are less likely to see those reductions.

The study was published in the American Journal of Public Health.

Maggie Li, the lead author, said in an email response to questions provided by NM Political Report that there is a well-documented pattern of environmental injustice in Native American communities, highlighting things like hard rock and uranium mining. She said the western United States has also seen increased wildfires as well as fracking, both of which can contribute to fine particulate matter pollution.

“Findings from this study provide additional evidence in line with what Native American activists and community members have described, that their communities have been facing greater air pollution burdens in recent years,” she said.

The researchers looked at air pollution data on a county-by-county basis and compared it to census data to determine which areas had high Native American populations. Li said the team looked at the average concentrations of fine particulate matter between 2000 and 2018. The study only included the contiguous 48 states.

“We chose this methodology to investigate potential disparities in air pollution at a nationwide scale and a policy-relevant unit of analysis,” Li said.

At the start of the study’s time frame, the counties with high populations of Native Americans tended to have lower levels of fine particulate matter. But, by 2018, that had changed. Li said that surprised the researchers.

Exposure to air pollution has been tied to a variety of health impacts and Li said the team hopes their study can “help guide policy to support efforts in monitoring and inform greater regulatory action of air pollution in Native American communities.”

Li is already building upon this study by looking at the various chemicals that contribute to the total fine particulate matter air pollution. She said the research will use a similar methodology and will quantify and compare the annual average concentrations of those various chemicals.

Li said her team is also participating in the Strong Heart Study, which looks at cardiovascular disease and risk factors among Native Americans in Arizona, North and South Dakota and Oklahoma. She said her team is planning to investigate the impacts of exposure to fine particulate matter on cardiovascular disease risks as part of that effort.

The study was funded by grants from the National Institute of Environmental Health Sciences.