The results of a recent study were more heartening than surprising.
Short version: If we clean up the air, kids' lungs will benefit.
The Children's Health Study, said to be one of the largest and most comprehensive investigations into the long-term effects of air pollution on children, for two decades followed 2,000 children in the Los Angeles area, infamous for the brown haze that once hung over it.
The research was run by the Southern California Environmental Health Science Center, part of the University of Southern California's Keck School of Medicine.
In 1998, nearly eight of 100 children aged 15 had "significant" lung deficits, or abnormally low lung function. By 2011, that number had dropped by more than half, more or less paralleling air quality improvements in the region.
The study, published earlier this month in the New England Journal of Medicine, also measured lung growth. It was more than 10 percent greater for children in the 2007-2011 group than in the earliest group.
The lung capacity of children with asthma improved the most, but all children benefitted, regardless of other factors such as education, ethnicity, exposure to tobacco smoke or pet ownership.
Lead author W. James Gauderman, professor of preventive medicine at Keck, noted this was the first good news from the long-running study, which had previously shown stunted lung development and a higher risk of asthma for children in areas with polluted air.
All this is important because childrens' lungs are growing fast. The number of airway sacs increase "dramatically" in the first few years of life, said Jeffrey M. Ewig, an attending physician in the Division of Pulmonary Medicine at The Children's Hospital of Philadelphia. Later, during adolescence, the overall size of the lungs grows.
"These are definitely vulnerable times," he said.
The study's findings " "Impressive data," Ewig said - matter not just to children, but to all of us, he added. The effects of early lung development set us on a lifetime trajectory. Indeed, the researchers have not seen a rebound in lung function among adults who were in the study when they were adolescents,
Want the flip side? Here's one of many: Scientists at the Centre for Research in Environmental Epidemiology in Spain studied 2,715 primary school children at 39 schools in Barcelona and found that where traffic-related pollution was highest, the students had the lowest rates of cognitive development.
Looking at yearly improvements in "working memory," the researchers found an 11.5 percent increase in children at schools with the lowest pollution, but only a 7.4 percent increase among children at schools with the highest. This study came out earlier this month an imaging study published in JAMA Psychiatry suggested that even pre-natal exposure to a particular kind of air pollution-polycyclic aromatic hydrocarbons, which come from traffic, coal-burning and smoking-can damage fetal brains and may impair behavior and learning.
This is what spurs groups like Moms Clean Air Force to action. The national nonprofit was formed four years ago and now has 450,000 members and chapters in nearly 20 states.
National field manager Gretchen Dahlkemper, a resident of Philadelphia, said she was far from surprised by the studies. The Clean Air Act has worked, she said. "The air quality is better across the country." But challenges remain. In particular, she wants to see more controls on smog-forming emissions from natural gas drilling sites and compressor stations. "These are not problems that we can't solve," she said. "We just need the political will to do it."
What interested Joseph O. Minott, executive director of the Clean Air Council, a nonprofit based in Philadelphia, was the Barcelona study's focus on the smallest particles of air pollution - black carbon and ultrafine particles. The U.S. regulates only coarse and fine particles. "Yet science is clearly showing what a serious public threat these tiny particles are," he said.
Back to more hopeful news: Public health researchers at UCLA have developed a prototype on-board air filtration system for school buses. In a study published Feb. 27 online in the journal Environmental Science and Technology, they found it reduces exposure to vehicular pollutants by up to 88 percent.
This, too, is big. About 25 million American children ride school buses every day. Remember when they used to line up outside schools, still idling and spewing diesel pollution? Now, anti-idling policies are the norm. Many buses also have been fitted with exterior pollution control devices.
Even so, school bus exhaust can penetrate into the cabin. Research has shown children on buses may actually be breathing more pollutants than people in cars nearby.
Ewig notes that the study did not delve into the impact-whether reducing air pollution inside the bus would result in, say, fewer asthma flareups or a reduced need for medication. "But it makes sense to have fewer pollutants in buses."
Overall, he said, these studies show "that we should continue to work on efforts to try to reduce pollution and not let our guard down."