Exposure to air pollution during pregnancy linked to autism diagnosis

Two new studies suggest that rising autism rates might be connected at least in part to air pollution from traffic. They are not the first to show a link between exposure to pollutants during pregnancy and the diagnosis of autism spectrum disorders. But both studies look at large populations and find a link with relatively low levels of pollutants.

In a study of 132,256 births in Vancouver, Canada, published Monday in JAMA Pediatrics, researchers detected an association between exposure to roadway pollution in utero and later diagnosis with autism. The study’s strengths were its large size and its method of diagnosing autism, which can be inconsistent....