Exposure to tobacco smoke was cut nearly in half among nonsmokers after New York's indoor-smoking ban went into effect, a new study finds.

The Associated Press reported July 19 that researchers who took saliva samples from about 1,600 nonsmokers found that levels of cotinine -- a nicotine metabolite -- declined 47 percent after the smoking ban was imposed. Samples gathered before and after the ban were compared.

The study was published in the July 20, 2007 issue of the U.S. Centers for Disease Control and Prevention's Morbidity and Mortality Weekly Report.