Children growing up in homes with water damage or dampness and exposed to higher levels of outdoor air pollution during early childhood face a greater risk of developing asthma, according to new research supported by the NIH’s Environmental influences on Child Health Outcomes (ECHO) Program. The large multisite study found that early-life exposure to fine particulate matter (PM 2.5 ) and indoor housing problems each independently raised asthma risk, while having a dog during infancy was linked to reduced risk.
Asthma affects millions of U.S. children, yet the environmental origins of the disease are complex. While previous research has tended to study exposures such as pollution or indoor allergens separately, this study shows that evaluating them together offers a more accurate picture of children’s risk. The ECHO Program, which brings together data from diverse U.S. populations, made this integrated analysis possible.
Drawing on data from 6,413 children across nine U.S. ECHO Study Sites, the research provides one of the clearest looks yet at how multiple early-life environmental factors interact to influence childhood asthma. The findings underscore the importance of assessing both indoor and outdoor environments together, rather than in isolation — an approach that prior studies often could not address due to limited sample sizes.
“Our research shows that to truly understand and prevent childhood asthma, we need to look at a child’s full environment—both the air they breathe outside and the conditions inside their home,” said Akihiro Shiroshita, a study author from Vanderbilt University School of Medicine. “Considering these factors together gives us a much clearer picture of what puts children at risk and how we can better protect them.”
Key Findings
Researchers evaluated children’s exposure to PM 2.5 during the first three years of life and combined that information with detailed data on early life housing conditions — including water damage, dampness, pet exposure, and dust mites. Childhood asthma was identified based on caregiver reports or physician diagnosis between birth and age five. The analysis also controlled for family and neighborhood factors to isolate the effects of environmental exposures.
The findings signal the need for additional research into how indoor and outdoor exposures interact and how early life interventions could help reduce asthma risk in children nationwide.
This collaborative research was published in Environmental Epidemiology .
About ECHO
The ECHO Cohort Consortium is a research program supported by the National Institutes of Health (NIH) with the mission to enhance the health of children for generations to come. ECHO Cohort investigators study the effects of a broad range of early environmental influences on child health and development. For more information, visit echochildren.org .
Environmental Epidemiology
Observational study
People
Individual and combined effects of indoor home exposures and ambient PM2.5 during early life on childhood asthma in us birth cohort studies
4-Feb-2026