US Wildfires Causes Most Air Pollution Exposure During Pregnancy

Wildfires are now the leading source of unhealthy levels of air pollution for pregnant women in the U.S., Reuters reported. Researchers also reported in Frontiers in Environmental Health that wildfire smoke is linked with adverse birth outcomes.

They studied about 64.5 million pregnancies in 48 states from 2003 to 2019, analyzing neighborhood exposure to tiny airborne particles 2.5 micrometers or less in diameter that travel deep into the lungs and bloodstream. Major sources of PM2.5 pollution include vehicle exhaust, industrial emissions, and wildfires.

Prenatal exposure to PM2.5 declined substantially between 2003 and 2019, but wildfire smoke’s contribution more than doubled from about 3.7% to 8.2%. By 2019, wildfire smoke was the main contributor to high-pollution days during U.S. pregnancies. That year, about two-thirds of “exceedance days”—when PM2.5 pollution exceeded 35 micrograms per cubic meter—were due to wildfire air pollution. The burden also falls disproportionately on low-income, rural, and Indigenous communities.

Researchers said healthcare providers in fire-prone regions should include wildfire risk assessment and education in prenatal care, focusing on communities with limited perinatal healthcare infrastructure. Enhanced air quality monitoring, early warning systems, and the distribution of climate adaptation technologies like air filters, masks, and clean air shelters may help reduce wildfire-related PM2.5 burdens.