Researchers have now linked air-pollution exposure before birth with lower IQ scores in childhood, according to study published in the August edition of Pediatrics.

Children whose mothers were exposed to the most pollution before birth scored an average of 4-5 points lower on IQ tests than children whose mothers experienced less exposure. This suggests that smog may adversely affect the developing brain.

The study followed 249 pregnant women who were exposed to typical urban air pollution, mostly from car, bus and truck exhaust. They wore backpack air monitors for 48 hours during the last few months of pregnancy to determine the level of exposure they received. The children of the mothers who were exposed to the most pollution scored lower on IQ tests given before the children started school at age 5.

For more, go to the August issue of Pediatrics: http://pediatrics.aappublications.org