Published March 3, 2015
For the first time, researchers have shown that reducing air pollution leads to improved respiratory function in children ages 11 to 15, a critical period of lung development.
Scientists have long known that air pollution is linked to smaller lung capacity and compromised breathing in children. But it had not been clear whether, and to what extent, a reduction in air pollution over the years might prevent these problems.
The new study, conducted in southern California and published in the New England Journal of Medicine, provides evidence that better air quality, a result of stricter regulation, improved health among children, experts said.
Morton Lippmann, a professor of environmental medicine at New York University School of Medicine, predicted that within the next few years, when federal emission standards are up for review, “this kind of information will play a major role.”
Over 17 years, researchers at the University of Southern California studied air-pollution levels as they declined in five regional communities. The scientists also measured breathing capacity in 2,120 schoolchildren from the communities during three periods: 1994-98, 1997-2001 and 2007-11.
The communities included the port city of Long Beach, as well as the inland city of Mira Loma, where mountains trap pollution blown eastward from the coast and downwind from agricultural production.
During those years, federal and state emission standards lowered the billowing output of California’s automobiles, diesel trucks, refineries, ships and trains. By the study’s conclusion in 2011, fine particulates had fallen by 50 percent and nitrogen dioxide levels by 35 percent in the communities.
As emission standards tightened and the air became cleaner, the scientists found that lung development in children born in later years was more robust than in those born earlier. Moreover, the percentage of children with significantly impaired lung function declined during the study period, from 8 percent to 3.5 percent.