Rob S. McConnell, M.D., William J. Gauderman, Ph.D., Edward Avol, Frank Gilliland, Ph.D., M.D.
University of Southern California
P01ES011627, R03ES022719, R01ES023262, P30ES007048
Research, supported in part by NIEHS, shows that decreases in ambient air pollution in Southern California were associated with significant reductions in respiratory symptoms in children with and without asthma.
Since 1992, air pollution reduction policies and strategies have significantly improved air quality across Southern California. To find out how these improvements affected bronchitic systems, the researchers examined data from a total of 4602 children in eight Southern California communities. They were all part of the Southern California Children’s Health Study over three time periods — 1993 to 2001, 1996 to 2004, or 2003 to 2012 . Bronchitic symptoms included a daily cough for three or more consecutive months, congestion or phlegm not related to a cold, or inflammation of the mucous membranes.
The authors report that decreases in ambient concentrations of nitrogen dioxide, ozone, and particulate matter — less than 10 microns and less than 2.5 microns — were associated with significant decreases in bronchitic symptoms in children with and without asthma. Children with asthma showed proportionally larger symptom reductions that remained similar during follow-ups up to age 15. Communities with the highest improvements in air quality also exhibited the largest reductions in bronchitic symptoms.
Although the study doesn’t provide a causal link between air pollution reduction and improved bronchitic symptoms, the findings support the potential benefit of air pollution reduction on asthma control.
Citation: Berhane K, Chang CC, McConnell R, Gauderman WJ, Avol E, Rapapport E, Urman R, Lurmann F, Gilliland F. 2016. Association of changes in air quality with bronchitic symptoms in children in California, 1993-2012. JAMA. 2016 (14):1491-1501.