Prenatal exposure to air pollution specifically fine particulate matter (PM2.5) and nitrogen dioxide (NO2) increases the risk of severe respiratory distress in newborn babies, according to a study, thus revealing a better understanding of infant respiratory distress, the leading cause of admission in neonatal intensive care units and death among infants worldwide.

Mothers’ exposure to air pollution while pregnant is known to be associated with adverse long-term respiratory issues, such as asthma, in their children. However, what we didn’t know is that maternal exposure to air pollution could cause babies to suffer severe respiratory distress soon after birth, said Chintan K Gandhi, assistant professor of pediatrics at Penn State and corresponding author of the paper, about the need to conduct the study. It is published in the journal Environmental Health Perspectives

To conduct their study, the researchers analyzed data from the Maternal-Infant Research on Environmental Chemicals (MIREC) Study led by Health Canada. The MIREC Study team estimated the women’s exposures to PM2.5 and NO2 beginning three months prior to pregnancy through the end of the third trimester by using models based on satellite information and ground-level air quality monitoring devices.

The MIREC team found that during the study period, the women were exposed to PM2.5 concentrations ranging from 1.47 to 23.71 micrograms per cubic meter of air (?g/m3), with a median of 8.81 ?g/m3, and NO2 concentrations ranging from 1.72 to 53.10 parts per billion (ppb), with a median of 18.02 ppb. To provide context, the U.S. Environmental Protection Agency provides standards for maximum annual exposures of 9.0 to 10.0 µg/m3 for PM2.5 and 53 ppb for NO2.

However, Gandhi said, “There really is no safe level of air pollution.”

Using data from the MIREC study, the team led by Penn State researchers examined associations between the mothers’ exposure to air pollution and physician-diagnosed respiratory distress in newborns. The examination extended beyond diagnosis to encompass the severity of respiratory distress, quantified by the necessity for oxygen, mechanical ventilation and systemic antibiotics in the infants.

“This nuanced approach provides a comprehensive understanding of the intricate relationship between maternal air pollution exposure and the varying degrees of respiratory distress observed in newborns,” Gandhi said.