Traffic pollution linked to nearly 2 million new cases of childhood asthma a year, study finds
As more people trade in old gas guzzlers for electric cars, new research on traffic-related air pollution suggests the switch could benefit millions of children a year.
George Washington University researchers studied ground concentrations of nitrogen dioxide in big cities around the world while tracking new cases of asthma that developed in children from 2000 to 2019. They found that nitrogen dioxide — a pollutant that primarily comes from tailpipe vehicle emissions — might have caused nearly 2 million new cases of pediatric asthma every year, according to the study published in the journal Lancet Planetary Health.
“Air pollution continues to be a major cause of asthma among children around the world,” said Susan Anenberg, co-lead author of the study and an environmental and occupational health professor at the Washington, D.C., university. “Not just an exacerbating actor but a cause.”
The study also found that two-thirds of the estimated 1.85 million new cases of childhood asthma in 2019 occurred in urban areas.
The findings add to a 2019 George Washington University study linking nitrogen dioxide to about 13% of global pediatric asthma cases and up to 50% in the world’s 250 biggest cities.
“Traffic pollution causing asthma is nothing new,” said Dr. Purvi Parikh, an allergist and immunologist with the Allergy and Asthma Network, a nonprofit for allergy, asthma and immune conditions. “We’ve known this for a very long time.”
Asthma is the most common chronic medical condition among children, affecting more than 6 million kids in the United States, according to the American Lung Association.
But the condition “is very preventable and manageable if we’re able to get our act together on improving air quality,” Parikh said.
With asthma, the lungs and airways are easily inflamed by triggers such as allergies, viral infections or airborne particles, making it difficult to breathe.
Unmanaged asthma can lead to asthma attacks — the leading cause of emergency department visits, hospitalizations and missed schools days among children.
“In the U.S. alone, about 10 people die from asthma each day, and this was before the pandemic,” Parikh said. “It’s 100% preventable and tragic because those deaths shouldn’t be occurring.”
The new study shows pediatric asthma cases linked to nitrogen dioxide declined from 20% in 2000 to 16% in 2019. The researchers said this modest improvement shows clean air initiatives in Europe and the United States have benefited children, especially those living in neighborhoods near busy roadways and industrial sites.
“Nitrogen dioxide is a highly urban pollutant,” Anenberg said. “It sticks pretty close to its emission sources.”
Unlike nitrogen dioxide, particulate matter travels the globe. A second study published by George Washington University researchers found 1.8 million “excess deaths” in 2019 can be linked to this air pollutant.
The modeling showed 86% of adults and children living in cities around the world are exposed to a level of particulate matter that exceeds World Health Organization guidelines of five micrograms per cubic meter of air.
The Environmental Protection Agency said in June it will reconsider revising the current U.S. standard, which is 35 micrograms.