Less smog means kids have healthier lungs, Southern California study finds

Less smog means children’s lungs are healthier in Southern California, and probably across North America, says a study in the New England Journal of Medicine.

The new study shows hard evidence for a trend that the public often doesn’t believe: Pollution controls on vehicles and in industry are giving us cleaner air.

The children measured in and near Los Angeles, famous for its smog, can take deeper breaths than children 20 years ago.

Where California doctors 20 years ago reported “abnormally low” lung function in eight out of 100 younger teenagers, they found this in only 3.6 of 100 children recently. That’s close to the average of 2.5 per 100 normally found in areas with clean air.

The University of Southern California Children’s Health Study measured lung development between the ages of 11 and 15 and reports “large gains for children studied from 2007 to 2011, compared to children of the same age in the same communities from 199498 and 1997-2001.”

The study authors add that “though conducted in Southern California, this research is relevant to all cities affected by air pollution.” Specific findings include: “Children’s lungs grew faster as air quality improved. Lung growth from age 11 to 15 was more than 10 per cent greater” in the modern kids compared with those 20 years earlier.

Modern children are equally likely to have asthma, but those with asthma today have better lung development than children with asthma 20 years earlier.

After the teenage years it’s too late to grow bigger, stronger lungs, even if the air does become cleaner.

Health studies on children led to many of the clean-air laws we have today.

In the 1980s, a project at Harvard University called the Six Cities study found that children in heavily-polluted cities had more respiratory trouble than those in cities with moderate pollution or clean air. The children breathing dirty air had more chronic cough and bronchitis, and were less able to draw a deep breath.

The Six Cities study also looked at adults, counting deaths from diseases such as lung cancer and emphysema. But it was the finding of lung damage in elementary schoolchildren that led to political changes.

Both Canada and the United States began requiring that cars must burn fuel more completely, and industries must emit fewer microscopic particles from burning coal.

In 2014, Ontario shut down its last coal-burning electrical generating station. The Ontario Clean Air Alliance called Ontario’s phaseout of coal “the largest single action on climate change in North America.”

Ontario has gone from having as many as 50 “smog days” per year shortly after 2000 to having about five per summer today, the group notes. (The recession was partly responsible, as factories that shut down or scaled back in 2009 haven’t been replaced.)

In California, the long-running study of children has reported for years on the damage done by dirty air. Dr. James Gauderman, its lead author, said the new paper represents the study’s first good news.

“It’s strange to be reporting positive numbers instead of negative numbers after 20 years,” he said.