It comes as no surprise that environmental degradation has severe health repercussions. As we continue to release toxins into the environment, we are left with no choice but to breathe in the polluted air and compromise our bodies’ normal functions. Recent studies have even shown that air pollution is slowing cognitive development in children because of inflammation occurring in the brain.

However, hope may be restored in the Los Angeles basin, as a 20-year study has shown that improved air quality has led to the direct improvement of lung development in children. Researchers from the University of Southern California Children’s Health Study published their findings in the New England Journal of Medicine, displaying how increased implementation of environmental health policies also facilitated healthy lung development in LA’s younger residents.

During the study, researchers examined lung development in three groups of children who were between the ages of 11 and 15 in 1994-98, 1997-2001, and 2007-2011. Following more than 2,000 students from various LA areas like Long Beach, Mira Loma, Riverside, San Dimas, and Upland, lung function and strength was compared with air quality monitoring. To test lung function, researchers asked students to blow into a spirometer, an instrument that can measure both lung size and strength by reading total lung volume, and the amount of air blown out per second. This test was run three times throughout the study, once when the children were 11, and again when they were 13 and 15. Air quality stations were also placed in the five communities, taking continuous key measurements of the amount of pollutants during the time of the study.

After the 20 years of research, the study found that as air pollution decreased, lung function and strength in the children of this age group increased. Even with varying factors such as age, gender, ethnicity, height, respiratory illnesses, etc. taken into consideration, the results were still the same. “We saw pretty substantial improvements in lung function development in our most recent cohort of children [between 2007-2011],” said Professor W. James Gauderman from the Keck School of Medicine at USCD. “It is strange to be reporting positive numbers instead of negative numbers after 20 years.”

Gauderman and his colleagues studied the effects on lung development after exposure to two harmful pollutants, nitrogen dioxide and particulate matter, of a diameter under 2.5 microns (PM2.5), fell approximately 40 percent between 2007 and 2011 compared to 1994-98. In 2011 particularly, federal and state regulations on pollutants made a difference, as nitrogen oxide concentration fell below the federal standard throughout the LA basin. As a result of this drop, children with abnormally low lung function at age 15 fell from almost eight percent between 1994-98, to 6.3 percent in 1997-2011, to finally 3.6 percent of children between 2007-2011. Children’s lungs also grew faster as air quality improved; children in the 2007-2011 bracket experienced 10 percent greater lung growth than those from 1994-1998.

“Reduced lung function in adulthood has been strongly associated with increased risks of respiratory diseases, cardiovascular diseases, and premature death,” Gauderman said. “Improved air quality over the past 20 years has helped reduce the gap in lung health for kids inside, versus outside, the LA basin.” These benefits from cleaner air prove to be life-long, according to Gauderman, as overall lung development improved during these key stages of childhood. Adults who grew up during times of poorer air quality were less likely to rebound, however, suggesting just how vital clean air is to long-lasting lung health.

Most importantly, the study found that all children benefit from improved air quality. Lung development for children with asthma improved twice as much as those living in areas with poorer air quality. Children without asthma also showed improvements in lung capacity, despite differences in education, ethnicity, tobacco exposure, pet ownership, and various other factors that affect lung development.

The study also shows applicability outside of the LA area. Gauderman says, “We expect that our results are relevant for areas outside southern California, since the pollutants we found most strongly linked to improved heath — nitrogen dioxide and particulate matter — are elevated in any urban environment.”

Despite the upward trend toward environmental and human health, Gauderman cautions that this trend may be temporary if we do not keep our mind toward reducing pollution. “We can’t get complacent,” he said, “because not surprisingly, the number of vehicles on our road is continually increasing. Also, the activities at the ports of LA and Long Beach, which are our biggest polluting sources, are projected to increase. That means more trucks on the road, more trains carrying cargo.”

As a result, the gains indicated by the study are in no way fixed. The growing drought in California is also expected to raise the amount of particulate matter within the air. “We have to maintain the same sort of level of effort to keep the levels of air pollution down,” said senior author Frank Gilland, Hastings Professor of preventive medicine at the Keck School. “Just because we’ve succeeded now doesn’t mean that without continued effort we’re going to succeed in the future.”

Tackling the immense problem of air pollution may seem daunting, but it becomes ever the more necessary as it continues to adversely affect our health. Though Gauderman and Gilland’s study shows promise for the future of air quality in relation to healthy development, as they say, complacency is our greatest enemy. We must keep our minds toward improving air quality, not just for our own sake but for our children’s as well.

Source: Gauderman J, Gilland F, Avol E, et al. The Effect of Air Pollution on Lung Development from 10 to 18 Years of Age. New England Journal of Medicine. 2015.