Children Exposed to Air Pollution at School May Be Cognitively Delayed, Study Finds

Is Air Pollution Harming Children's Brains?
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Air pollution's latest victim: Children's cognitive development.

Elementary school children who are exposed to chronic air pollution may develop cognitive abilities more slowly than children who breathe cleaner air, according to a study published Tuesday in the journal PLOS Medicine.

Researchers with the Centre for Research in Environmental Epidemiology (CREAL) surveyed over two thousand Barcelona children at 39 schools, between ages 7 and 10, every three months for one year. Researchers chose schools where the socioeconomic status of the students would be similar, because evidence already exists correlating lower socioeconomic status with greater harm from air pollution.

At each visit, they tested for cognitive skills like working memory and attentiveness, since both are known to grow steadily during that age range. Working memory refers roughly to the capacity to think about more than one thing at the same time, and is tied to one's ability to learn new concepts and also to general intelligence. Researchers found that children who attended school in areas with high levels of air pollution from nearby traffic improved in these cognitive areas more slowly than their counterparts at schools less exposed to air pollution. For example, children in low-pollution areas improved their working memory over the course of the year by 11.5 percent. Children in higher-pollution areas only improved in this area by 7.4 percent. That means children at the higher-pollution schools would be less developed at any given time than their counterparts at doing tasks like keeping mental tabs on what solutions they've already tried while attempting to solve a puzzle, per one example given by the New York Times.

The findings suggest "that the developing brain may be vulnerable to traffic-related air pollution well into middle childhood," or age 7 through age 10, the authors wrote, "a conclusion that has implications for the design of air pollution regulations and for the location of new schools."

Air pollution has been linked to a staggering number of health problems in recent years. Cardiovascular disease, asthma and cancer, among a host of other ailments, have all been tied to increased air pollution exposure, as has an array of adverse pregnancy outcomes, such as early birth and low birth weight. A recent study concluded that pregnant women who are exposed to high levels of air pollution during the third trimester of pregnancy may be twice as likely to give birth to children with autism. Yet another study linked exposure to higher suicide rates among middle-aged men. And the World Health Organization recently blamed air pollution for 7 million premature deaths in 2012 alone, which amounts to one in every eight people who died that year.