The Chalkboard: Recent EPA Children’s Health Research Updates

July/August 2025

Studying the Potential Impacts of Air Pollution on Young Hearts and Lungs

Anyone who has had the privilege to be in the delivery room when a child is born knows how carefully doctors and nurses watch for those first few breaths from a newborn. A couple of big gulps of air, followed by a robust outburst of crying are good indicators. Combined with a rich skin hue and it’s a good bet a healthy baby has arrived. Strong lungs and heart are key. 

And because lung and heart development span from the earliest stages of life to well past those first few breaths, researchers are working to identify if exposure to air pollution during certain time periods along the way could lead to long-term health impacts. Pinpointing such “windows of susceptibility” could provide key information for protecting children’s environmental health. 

Three recent EPA studies focused on providing just that kind of information.    

1. Wildfire Smoke and Pediatric Prescriptions of Respiratory Medicine

   With wildfire season growing longer and more severe in recent years, an increasing number of communities are facing health challenges related to smoke exposure. To better understand how such events might put children at greater risk, EPA researchers and their partners conducted the first study to examine associations between gestational and postnatal exposure to wildfire smoke and prolonged use of prescription respiratory medicines. 
   
   To do so, they combined publicly available prescription drug data from six fire-prone western U.S. states with assessments of air pollution exposures during “smoke-days.” They did find an association between increases in wildfire smoke and more prescriptions issued: “…an increase in the repeated, prolonged use of lower respiratory medications in the first 3 yr after exposure among children who were exposed to wildfire smoke during the 3^rd trimester and the first 12 weeks after birth.” 
   
   Overall, the researchers conclude that there are potential long-term benefits to taking protective measures that reduce wildfire smoke exposures to pregnant women and infants.

2. Air Pollution and Preterm Birth: Comparing Averages to Repeated High Exposure Days 

   A host of studies analyzing data on average air pollution concentrations over time have found associations between exposures during pregnancy and preterm birth (PTB). Less understood, however, are potential associations between PTB and exposure to periodic spikes of air pollutants such as ozone (O₃) and particulate matter (PM), which can have high levels of variability over short periods of time. 
   
   To address that knowledge gap, EPA researchers and partners conducted a study comparing the two. To do so, they combined data collected from more than 1.3 million births in North Carolina (part of the North Carolina Birth Defect Monitoring Program) with air quality concentrations from EPA’s Fused Air Quality Surface Using Downscaling model. They assigned exposure levels for both trimester-average and daily threshold exceedances of O₃ and PM.  
   
   Findings suggest that considering average exposures alone might leave out important information for developing air pollution guidelines that are protective of young children. 
   
   “When considering the impact of air pollution on birth outcomes, both the magnitude and frequency of exposures should be considered, particularly for ozone which may exhibit greater temporal viability and diurnal peaks,” the researchers note.  

   
   3.  Air Pollution and the Congenital Heart Defect Tetralogy of Fallot  

   EPA researchers and partners conducted an exploratory study looking for evidence of links between tetralogy of Fallot (TOF)—the most common complex congenital heart defect—and prenatal exposures to air pollution. The study focused on how air pollutant exposure might disrupt the biochemistry of DNA signaling during key periods of development.
   
   To do so, they used DNA from newborn residual blood spots from a large North Carolina study to compare 24 infants with TOF against a control group. They then assigned air pollution exposure levels for particulate matter and ozone during obstetric weeks three through eight, a critical window of susceptibility for congenital heart defects. 
   
   What they found was that TOF cases tended to have higher exposures to both particulate matter and ozone. In addition, they observed associations between TOF cases and DNA methylation at regions important for metabolism, inflammation, and immune response pathways. 
   
   “This study is among the first to assess relationships among air pollutants, DNA methylation, and TOF case status using residual blood spots. This exploratory work sets the stage for larger studies to investigate these relationships,” the researchers concluded. 

Sources

1. Jardel, H., Rappazzo, K. M., Luben, T. J., Keeler, C., Staley, B. S., Ward-Caviness, C. K., ... & Dhingra, R. (2024). Gestational and postnatal exposure to wildfire smoke and prolonged use of respiratory medications in early life. Environmental Research: Health, 2(4), 045004.
2. Mowla, S. J., Krajewski, A. K., Wilkie, A. A., Rappazzo, K. M., & Luben, T. J. (2025). Air pollution and preterm birth: comparing trimester average and repeated threshold exposure metrics in a North Carolina birth cohort, 2003–2015. Journal of Exposure Science & Environmental Epidemiology, 1-11.
3. Luben, T. J., Roell, K., Harrington, C. E., Stingone, J. A., Ward‐Caviness, C. K., Desrosiers, T. A., ... & Olshan, A. F. (2025). Using Residual Newborn Blood Spots to Investigate CpG Methylation in Relation to Air Pollution and Congenital Heart Defects. Birth Defects Research, 117(4), e2473.

Read previous highlights in The Chalkboard archive. 

 Learn more about EPA Children's Health Research