Images courtesy of USC

Young teens and children in Southern California breathe easier than those from past decades, according to a 20-year study conducted by USC, which surveyed area cities including Long Beach.

The survey found that the lung function of children ages 11 to 15 is better than children who grew up in the area from 1994 to 1998 and 1997 to 2001, as a result of improving air quality in the Los Angeles basin.

The study tracked the health of more than 2,000 children in Long Beach, San Dimas, Riverside, Mira Loma and Upland for more than two decades. It adjusted for age, gender, ethnicity, height, respiratory illness and other variations.

The survey gives strong evidence of the health benefits of better air, according to USC.

“We saw pretty substantial improvements in lung function development in our most recent cohort of children,” said lead author W. James Gauderman, professor of preventive medicine at the Keck School of Medicine of USC in a statement. “It’s strange to be reporting positive numbers instead of negative numbers after 20 years.”

Prior to this study, previous findings from a similar study showed an increase in stunted lung development for children in areas with heavy air pollution, as well as a higher risk of asthma for children living near busy roadways.

According to the study, a key finding was that combined exposure to nitrogen dioxide (NO2) and particulate matter of diameter under 2.5 microns (PM2.5) fell about 40 percent for the third cohort of 2007 to 2011 compared to the first cohort of 1994 to 1998.

It also found that children’s lungs grew faster as air quality improved and the percentage of children in the study with abnormally low lung function at age 15 dropped from nearly 8 percent for the 1994-98 cohort, to 6.3 percent in 1997-2001, to just 3.6 percent for children followed between 2007 and 2011.

“That compares to 2.5 percent by age 18 for children from the first two cohorts who lived in cities with cleaner air, such as Lompoc and Santa Maria,” according to a statement from USC. “Cuts in federal funding forced the researchers to exclude those cities in the last cohort and focus only on areas with heavier air pollution.”

The study went on to emphasize that the “growing years are critical for lung development,” citing a monitor of adults who participated in the study as adolescents. These participants have not rebounded after their teenage years, according to the study.

“Their lungs may have lost the opportunity to grow anymore,” Gauderman said.

While the study is a step in the right direction, Gauderman cautioned against possible things that could hinder complete success.

“We can’t get complacent, because not surprisingly the number of vehicles on our roads is continually increasing,” he said. “Also, the activities at the ports of L.A. and Long Beach, which are our biggest polluting sources, are projected to increase. That means more trucks on the road, more trains carrying cargo.”

“These gains really aren’t fixed,” added senior author Frank Gilliland, Hastings Professor of preventive medicine at the Keck School in a statement. “We have to maintain the same sort of level of effort to keep the levels of air pollution down. Just because we’ve succeeded now doesn’t mean that without continued effort we’re going to succeed in the future.”

Gilliland also warned of the potential impacts the state’s historic drought could have on raising particulate pollution.

The study’s third cohort of 2007 to 2011 also came at a time for financial health when the economy shrank and emissions fell during the Great Recession.

However, the study also shows that air pollution and growth can coexist over the long term. The economy and population in the basin has grown since the cohort of 1994 to 1998.

“Our results suggest that better air quality in future will lead to even better lung health,” Gauderman said.