Reduced pollution in the Los Angeles Basin has resulted in significantly better lung function for children today compared to children from the same communities in the 1990s, according to a new study.
Improved air quality has led to significant positive impacts on children's lung function during the important teenage development years as a result of air quality standards, James Gauderman of the University of Southern California said.
"However, despite improved air quality, several communities in Southern California still do not meet the standards set by EPA to protect human health," Gauderman said. "The research by our group and other groups should provide the kind of scientific evidence that will inform future standard-setting decisions."
The research demonstrates that air pollution affects the respiratory health of all children, Gauderman said. It was reported March 5 in the New England Journal of Medicine.
"Other research from our group has demonstrated that asthmatic children living in more polluted communities have increased risks of respiratory symptoms, including bronchitis, chronic cough and phlegm, compared to children living in less polluted communities," he said.
Lungs develop rapidly during the teenage years, with development ending as children transition into adults, Gauderman said.
"If a child has deficits in lung development due to pollution exposure, they may carry those deficits with them for the rest of their life," he said. "Many other studies have demonstrated that low lung function in older adulthood is strongly associated with lung disease, heart disease and reduced lifespan."
Gauderman said his group focused on five polluted Southern California communities, including Long Beach, Mira Loma, Riverside, San Dimas and Upland, and within each community, followed three groups of children from 11 to 15 years of age.
The first group was followed from 1994-98, the second from 1997-2001 and the third from 2007-11.
Over the period from the first to third group, air quality improved substantially across these communities, with an average reduction of about 50 percent in PM2.5 (fine particulate matter) and 35 percent in NO2, or nitrogen dioxide.
The four-year growth in lung function improved by about 10 percent comparing the third to the first group, with associations to the corresponding changes in both PM2.5 and NO2 that were statistically significant.
The proportion of children with low lung function at age 15 declined significantly as air quality improved, with 7.9 percent in the first cohort, 6.3 percent in the second cohort and only 3.6 percent in the third cohort, Gauderman said.
Weather also plays a role in air pollution, AccuWeather.com Western Weather Expert Ken Clark said.
"If there are big temperature inversions, this traps pollutants under that inversion and allows those pollutants to build," Clark said. "This occurs in Southern California and also in the Central Valley. If the air is well mixed, then so are the pollutants."
AccuWeather, among its suite of forecasts, has an air quality forecast.
Residents can use the forecast in trying to figure out if some days, it may not be the best thing to do to exercise outside or not, Clark said.
"On high polluted days, it's best to keep outside exercise to a minimum," he said.
Although the study was conducted in Southern California, the pollutants with declining levels that were found to be most closely related to improved children's health (NO2 and PM2.5) are elevated in any urban environment, Gauderman said.
"We would therefore expect that reductions in levels of these pollutants should lead to improved health of children in any urban setting," he said.