Air Pollution

Southern California’s efforts to reduce air pollution are apparently allowing children there to breathe a little easier.

In a study published today in The New England Journal of Medicine, researchers concluded the decrease in air pollution over two decades has significantly benefitted the respiratory systems of children who live in the area.

Scientists conducted their research in five Southern California communities during three time periods: 1994 to 1998, 1997 to 2001, and 2007 to 2011.

In each grouping, the average age of a child was 11 at the start of a time period and 15 at the end of it.


Researchers measured the lung function of a total of 2,120 children every year during those three time periods. The children blew into a device called a spirometer that measured how much air they could breathe out in one second and how much air they could push out in one long exhale.

Over the course of the study, the percentage of 15-year-olds with significantly impaired lung function declined from 7.9 percent to 3.5 percent.

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Researchers also found that the lung development in children tested in the later years of the study was more robust than in children tested earlier.

The improvement in lung function coincided with a drop in air pollution in Southern California communities. Over the 17 years of the study, fine particulates dropped by 50 percent and nitrogen dioxide levels fell by 35 percent.

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“This study shows an association between secular improvements in air quality … and measurable improvements in lung-function development in children,” the authors of the report wrote.

Air pollution has been linked to an increased risk of asthma in children. Moreover, decreased lung function in adults has been associated with an increased risk of heart disease.

Researchers said the new study is the first time a reduction in air pollution over a period of years has been linked to an improvement in respiratory function in children.

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