pollution

Study Links Higher Air Pollution to Increased Childhood Asthma, Highlights Unequal Burden in Black and Urban Communities

Posted on by Jodi Snare

Higher exposure to fine particulate matter, nitrogen dioxide, and ground-level ozone was associated with increased asthma incidence in children up to age 10, according to a new study funded by the Environmental influences on Child Health Outcomes (ECHO) Program at the National Institutes of Health. Notably, children living in areas with higher proportions of Black residents or higher population density faced greater pollution-related asthma risk, despite overall air quality improvements in the U.S.

“Our findings show why it’s so important to keep reducing air pollution everywhere in the U.S. They also highlight the need to understand and tackle the deeper reasons why some communities are more affected than others,” said Veronica Wang, research fellow at the Harvard T.H. Chan School of Public Health.

Key Takeaways:

  • Higher levels of fine particulate matter, nitrogen dioxide, and ground ozone were each linked to more new cases of asthma in early childhood.
  • Fine particulate matter and nitrogen dioxide posed a greater asthma risk for children living in areas with more Black residents.
  • Children in more densely populated neighborhoods were also at higher risk from these pollutants.
  • The study looked at data from over 23,000 children born between 1981 and 2021 to find out which groups are more likely to develop asthma from air pollution exposure in early childhood.

The study analyzed extensive environmental and community data, highlighting the importance of reducing harmful exposures in the most affected neighborhoods.

This collaborative research was published in Environmental Epidemiology.

ECHO Study Observes Health Disparities in Air Pollution-associated Risk of Childhood Asthma

<< Back to Research Summaries

ECHO Study Observes Health Disparities in Air Pollution-associated Risk of Childhood Asthma

Authors: Veronica A. Wang, Rima Habre, Diane R. Gold, Antonella Zanobetti, et al.

 

Who sponsored this study?

The Environmental influences on Child Health Outcomes (ECHO) Program, Office of the Director, National Institutes of Health supported this research.

 

Why was this study needed?

Asthma is one of the most common chronic childhood diseases in the United States, affecting over 4.5 million children. Although air pollution levels have decreased over the past decades, individuals living in certain areas have seen lower reductions in air pollution and may also be more vulnerable to its effects. For this study, researchers examined sociodemographic disparities in the association between air pollution and incident childhood asthma until age 10.

 

What were the study results?

The study found that higher exposures to fine particulate matter, nitrogen dioxide, and ground ozone were associated with a higher incidence of asthma in the first 10 years of a child’s life. For fine particulate matter and nitrogen dioxide, children from areas with a higher proportion of Black residents or higher population density were identified being at a higher risk for air pollution-associated asthma.

Footnote: Results reported here are for a single study. Other or future studies may provide new information or different results. You should not make changes to your health without first consulting your healthcare professional.

 

What was the study's impact?

This study showed that sociodemographic disparities in air pollution-associated asthma persist despite reductions in the overall air pollution levels. The study highlighted the potential to mitigate childhood asthma risk by reducing air pollution and addressing the root causes of these disparities.

 

Who was involved?

The study involved over 23,000 children, born between 1981-2021, from 34 sites in the Environmental influences on Child Health Outcomes (ECHO) Program with data on asthma diagnosis until age 10 in the contiguous US.

 

What happened during the study?

During the study, the study team collected data on each participant’s asthma status, month of diagnosis, and length of their follow-up. They also collected sociodemographic data that included sex, race/ethnicity, maternal education, and more. Lastly, they used area-level data from the 1980-2019 Census Bureau and the American Community Survey on the percent of low-income residents, Black residents, residents with less than a high school education, unemployed residents, and female residents, and overall population density. The study team then analyzed this data, first examining the association between air pollution exposures (fine particulate matter, nitrogen dioxide, and ground ozone) and childhood asthma, then determining whether the sociodemographic and economic variables modified the air pollution-asthma association.

 

What happens next?

Future studies could help researchers better understand the root causes of susceptibility to air pollution. Additional studies with longer follow-up could also help researchers understand how asthma risk may change throughout childhood as the climate and environmental conditions change. Lastly, additional studies may help researchers understand how personal exposures affect asthma in children, including indoor sources of air pollution.

 

Where can I learn more?

Access the full journal article, titled “Disparities in the Association of Ambient Air Pollution with Childhood Asthma Incidence in the ECHO Consortium: a US-wide Multi-cohort Study,” in Environmental Epidemiology.

 

The content is the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Published August 2025

Read the associated research article.

Download this summary

ECHO Study Observes Health Disparities in Air Pollution-associated Risk of Childhood Asthma

 

Read More Related Research Summaries

Upper and Lower Airways

 

NIH Study Explores Pollution Exposure and Birth Outcomes in Pregnant Women Living in Historically Redlined Neighborhoods

Posted on by Jodi Snare

Residence in redlined census tracts during pregnancy was associated with higher exposure to PM2.5 and lower birth weight in a recent study funded by the Environmental influences on Child Health Outcomes (ECHO) Program. Redlining is the historical practice of designating certain neighborhoods, often where minority groups lived, as risky investments for lenders. Additionally, living in ungraded census tracts was linked to elevated PM2.5 exposure, lower birth weight, and increased odds of low birth weight. These findings underscore the complex nature of structural racism, suggesting that factors beyond redlining may contribute to ongoing inequalities in health outcomes. Further research is needed to explore these dynamics and their implications for maternal and infant health. Read the research summary here.

The Effect of Air Pollution on Time to Pregnancy

Posted on by Jodi Snare

Linda Kahn, PhD, MPH

Collaborative ECHO research, led by Linda Kahn, PhD, MPH at NYU Langone Health, suggests traffic-related air pollution, secondhand smoke, and formaldehyde are associated with longer time to pregnancy. Specifically, exposure to particulate matter and nitrogen oxide gases lowered couples’ chances of becoming pregnant. Traffic and the burning of other types of materials besides gas and diesel, such as wildfires or other sources of combustion, create particulate matter and nitrogen oxide gases.

These results are based on a systematic review of 33 articles pertaining to air pollution and time to pregnancy, an indicator of a couple’s reproductive health. The team’s research, titled “Indoor and outdoor air pollution and couple fecundability: a systematic review,” is published in Human Reproduction Update.

Mounting evidence suggests an association between air pollution and longer time to pregnancy. The goal of this review was to compare results from previous studies and identify whether different types of pollution, such as pollution from traffic, chemicals in the workplace, and secondhand smoke, are consistently related to time to pregnancy.

To conduct this research, the team searched six science libraries and reviewed 33 relevant articles published in English between January 1, 1990 and February 11, 2021. Of these 33 articles, eight examined air quality, six looked at secondhand smoke exposure, and 19 studied air quality in the workplace. Researchers assigned each article a quality score based on the study design and extracted relevant data on time to pregnancy.

“This review shows that certain chemicals can increase the amount of time it takes for a couple to conceive, which may cause stress and lead them to seek fertility treatments,” said Dr. Kahn.

Researchers still need more insight into exactly how these chemicals affect reproduction. Future studies should be designed to collect more accurate exposure data, ideally from personal air monitors.

“Our team is still uncertain about whether the air people breathe around time of conception is most important or if there are certain life stages such as puberty when individuals may be especially susceptible to the harmful effects of air pollution,” Dr. Kahn added.

The ECHO Program will provide a useful framework for collecting more detailed information on how chemical exposures across the life course affect reproduction.

Read the research summary.

Identifying and Addressing Limitations: The Effects of Air Pollution on Children’s Behavior and Brain Development

Posted on by Jodi Snare

Heather Volk, PhD
Johns Hopkins Bloomberg School of Public Health

In a recent article published in Environmental Research, ECHO researcher Heather Volk, PhD, of Johns Hopkins Bloomberg School of Public Health and her team summarized information on different ways to measure prenatal air pollution exposure. They also reviewed what scientists know about how air pollution affects children’s behavior and brain development.

To collect this information, the team reviewed previous publications on air pollution and child development and summarized the study results. They then took these findings and developed a plan to address shortcomings of the earlier work to advance children’s health.

The plan involves using advanced geographic models for common air pollutant exposures. Since more than 90% of ECHO cohorts have collected a physical address for their participants, ECHO has the ability to study pollutant exposures by geographic area. This has been a limitation commonly seen in this area of research. This summary data also allows researchers to determine if there may be enough ECHO participants in the future to study how air pollution can affect children’s brain development and behavior.

“This research confirms that ECHO provides a unique opportunity to study how air pollution can affect children’s brain development and behavior in a large, diverse study population,” Volk said. Given this information, the team hopes that future studies will examine prenatal air pollution exposure in ECHO participants to examine how it affects the brain.