Smoke-free air laws have been shown to reduce exposure to secondhand smoke among adults, and a new study shows a similar association in children and adolescents who do not live with a smoker at home.

The study, “Smoke-free Air Laws and Secondhand Smoke Exposure Among Nonsmoking Youth,” published in the July print issue of Pediatrics (published online June 7), examined data from the 1999-2006 National Health and Nutrition Examination Survey. It found children who live in a county with extensive smoke-free air laws had 39 percent lower prevalence of cotinine, the major metabolite of nicotine and a common biomarker of secondhand smoke exposure.

Smoke-free air laws did not have an impact on the cotinine levels of children who lived with a smoker at home. Study authors suggest interventions designed to prevent adults from smoking around children are needed.