A landmark study shows that kids in the Los Angeles area have significantly healthier lungs today than they did 20 years ago.
Over the last two decades, a team of researchers from the University of Southern California has measured lung function in over 2,000 children from five of SoCal’s smoggiest cities: Long Beach, Riverside, San Dimas, Upland and Mira Loma. The children were monitored for four-year stretches in three separate calendar periods: 1994-1998, 1997-2001 and 2007-2011.
As the study has progressed, its authors have found that children in areas with heavy air pollution exhibited stunted lung development. A higher risk of asthma was also associated with children living near busy roadways.
Over the last few decades, California has taken major steps to reduce its atmospheric pollution, phasing out inefficient car and truck engines; ditching the dirtiest fuels in school buses, lawnmowers and jet skis; offered local and state incentives for replacing older vehicles; and cleaning up oil refineries and manufacturing plants in the LA basin. In addition to its progressive energy portfolio standard, which calls for 33 percent of its electricity to be generated by renewable energy by 2020, the Golden State is also now a leader in solar power development, ocean management and climate change adaptation.
All of these measures have had a notable impact on California’s air quality. During the course of the 20-year USC study, the levels of two of the most harmful pollutants, nitrogen dioxide and PM2.5 (particulate matter produced by fossil fuel combustion that causes a range of adverse health effects), declined by up to 50 percent in the most polluted neighborhoods. Pollution in the ports of Long Beach and Los Angeles also showed major declines.
The result was that combined exposure to nitrogen dioxide and fine particulate matter fell by about 40 percent for the cohort of children studied between 2007 and 2011 compared to the first cohort of ’94-’98.
According to lead author W. James Gauderman, professor of preventive medicine at USC’s Keck School of Medicine, this drop in pollution correlated with improved lung health in the children they studied. “We saw pretty substantial improvements in lung function development in our most recent cohort of children,” Gauderman said in a news release.
The USC study shows that lung growth from age 11 to 15 improved by more than 10 percent for the ’07-’11 cohort compared to the first cohort, and abnormally low lung function at 15 dropped from eight percent (’94-’98) to 3.6 percent (’07-’11).
“It’s strange to be reporting positive numbers instead of negative numbers after 20 years,” said Gauderman.
National Geographic says the study, recently published in the New England Journal of Medicine, “may be the biggest success story in environmental health in modern America.”
The improvements in lung health were unprejudiced by race, exposure to cigarette smoke or pets in the home. In every community, the average lung capacity for children improved and the lungs of asthmatic children improved approximately twice as much as the lungs of other children.
“It’s remarkable,” Gauderman told the magazine. “This is one of the biggest turnarounds I’ve ever seen.”
Frank Gilliland of USC’s Programs in Biomedical and Biological Sciences told National Geographic that the lesson to draw from the study is a simple one: “scientifically that targeting pollutants actually makes kids healthier… These problems are fixable, and you can see big benefits.”