Pregnant women exposed to ozone and PM2.5 mixture in week 11 had 53% greater odds of preterm birth; repeated exposure weeks 9-14 tripled the risk. Current EPA air quality index rates these pollution levels as 'safe' because it measures single pollutants, missing dangerous combined effects during critical placental development.
Air pollution mixtures pose greater preterm birth risk than single pollutants
Pregnant women and infants face increased health complications and preterm delivery risks from unregulated multi-pollutant air exposure during critical pregnancy windows.