Wildfire-specific particulate matter exposure during pregnancy and early life airway outcomes

Wildfires are an emergent environmental health threat in the U.S. as climate change contributes to increased wildfire activity and severity. Wildfire smoke represents a growing contribution to overall fine particulate matter (PM2.5), with distinct physicochemical properties that may lead to higher toxicity. Ambient PM2.5 is recognized to adversely impact airway health, particularly among children. However, research on the early life respiratory impacts of wildfire-specific PM2.5 is limited and predominantly focused on postnatal short-term exposure and acute health effects. The potential impacts of prenatal exposure to wildfire smoke PM2.5 on early life airway health remain largely unknown. In fact, there are currently no published studies of prenatal wildfire smoke exposure and children’s airway health in prospective U.S. cohorts. The proposed Aims will evaluate associations between prenatal wildfire-specific PM2.5 exposure and airway outcomes in children under 24 months of age in the nationwide cohorts of the Environmental influences on Child Health Outcomes (ECHO) Program (N~10,000). Aim 1 will evaluate risk of airway symptoms (wheezing and asthma-related symptoms) and hospitalization (bronchiolitis and other acute respiratory infection) associated with average smoke PM2.5 and days with smoke PM2.5 during pregnancy. Aim 2 will explore the role of wildfire smoke exposure intensity, duration, and timing during pregnancy by evaluating how risk may vary in association with “smoke days” of increasing intensity and “smoke waves” of increasing duration and intensity. Aim 2 will also evaluate potential critical windows of exposure during different stages of fetal lung development. Aim 3 will identify vulnerable sub-populations with disproportionate risk of airway outcomes by exploring effect modification by fetal sex, geographic region, and neighborhood poverty rate. This research will be among the first to evaluate associations between wildfire smoke exposure and child airway health in the U.S., leveraging a geographically and socioeconomically diverse study population. The proposal directly supports the mission of the National Institute of Environmental Health Sciences to advance environmental health science, identify individual susceptibility, and conduct translational research to promote environmental justice. Project Number: 1R03ES037047-01 | Fiscal Year: 2025 | NIH Institute/Center: National Institute of Environmental Health Sciences (NIEHS) | Principal Investigator: CATHERINE KARR | Institution: UNIVERSITY OF WASHINGTON, SEATTLE, WA | Award Amount: $155,500 | Activity Code: R03 | Study Section: Social and Environmental Determinants of Health Study Section[SEDH] View on NIH RePORTER: https://reporter.nih.gov/project-details/11035709