Using machine learning, University of Utah researchers found that repeated exposure to combinations of common air pollutants in early pregnancy was associated with nearly three times greater odds of early preterm birth
July 16, 2026
Reposted from @theU. Brenna Kelly is an incoming postdoctoral fellow for the One-U Responsible Artificial Intelligence Initiative.
Pregnancy puts higher oxygen demands on the body, so expectant mothers breathe significantly more air over the course of a day. When air quality is bad, they’re also breathing in more harmful pollutants.
Many studies have linked individual air pollutants, such as fine particulate matter (PM2.5) or ozone, to early preterm birth—delivery before 34 weeks’ gestation, when infants face higher risks of health complications. But those studies don’t reflect the reality that people are often exposed to mixtures of pollutants simultaneously.
In a new University of Utah study of 44,874 first-time mothers in Utah, researchers found that exposure to even moderate levels of multiple air pollutants may increase the risk of preterm birth when experienced together—especially during critical stages of pregnancy.
The findings raise questions about whether current air quality index (AQI) ratings—typically based on the single pollutant posing the greatest harm—may be missing serious health risks to the public.
“People are exposed to multiple things at once, over multiple times,” said Brenna Kelly, lead author on the paper. Kelly is a recent graduate of the University of Utah’s Population Health Sciences Ph.D. program and an incoming Responsible AI postdoctoral fellow. “It may matter when pollution is slightly elevated for multiple chemicals.”
Plus, read Kelly's related opinion piece in The Salt Lake Tribune.