Improved air quality in Southern California is associated with improvements in children's respiratory function. Air pollution levels in the region have been improving over the last several decades because of aggressive policies to improve air quality there.
This is the first time that researchers have shown that improving air quality leads to better lung function during a critical time when the lungs are developing.
A study published in the New England Journal of Medicine looked at three separate groups of children enrolled in the Children's Health Study. The first two groups were fourth graders from 12 California communities in 1992 to 1994 and 1995 to 1996, respectively. The third group were kindergartners and first graders in 13 California communities in 2002 to 2003. The researchers measured breathing capacity in a total of 2,120 children in these groups and also studied air pollution levels in five regional areas.
The study found that children born later had much better lung development than those born when pollution was worse. The percentage of children with significantly impaired lung function declined from 8% to 35%. During the period covered by the study, particulates in the air had fallen by 50% and nitrogen dioxide levels by 35%. These two pollutants are among those most effectively reduced by air quality policies.
"If we make the not-unreasonable assumption of causality, the magnitude of the effects we observed and the importance of lung function over the course of the human lifetime justify the efforts that have been made to improve air quality" the study concluded.
Air quality was a serious issue in Southern California for many years because of pollution from industry and the huge numbers of cars and trucks in the area, and because the geography of the region traps polluted air over the Los Angeles area.
