Study Links Specific Air Pollutants to Asthma Attacks in Children

A new study links elevated levels of specific outdoor air pollutants to distinct changes in the airways during asthma attacks in children and adolescents.

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An NIH-funded study found that moderate levels of two outdoor air pollutants—ozone and fine particulate matter—are associated with non-viral asthma attacks in children and adolescents who live in low-income urban areas. 

The observational study is one of the first to link elevated levels of specific outdoor air pollutants in particular cities to distinct changes in the airways during asthma attacks not triggered by respiratory viruses. Findings were published in The Lancet Planetary Health.

In the study, conducted by the NIAID-funded Inner City Asthma Consortium, investigators examined the relationship between air pollutant levels and asthma attacks among 208 children ages 6 to 17 years who had attack-prone asthma and lived in low-income neighborhoods in one of nine U.S. cities. The researchers validated the associations they found in an independent cohort of 189 children ages 6 to 20 years with persistent asthma who also lived in low-income neighborhoods in four U.S. cities.

The investigators followed the children prospectively for up to two respiratory illnesses or six months, whichever came first. They matched each illness with air quality index values and levels of individual air pollutants recorded by the Environmental Protection Agency in the relevant city on the dates surrounding the illness. They subsequently adjusted their data for city and season to decrease the impact of these variables on the findings.

The scientists found that asthma attacks had a non-viral cause in nearly 30% of children, two to three times the proportion seen in non-urban children, according to previously published reports. The study also identifies links between exposure to the two pollutants and molecular changes in the children’s airways during non-viral asthma attacks, suggesting potential mechanisms for those attacks.