Exposure to second hand smoke at home and work among nonsmokers.

Exposure to second hand smoke (SHS) is associated with adverse health effects. This study was undertaken to assess comparative levels of exposure to SHS at home and work among nonsmokers aged ⩾12 years. Data from National Health Examination Survey for 1999-2010 were analyzed to estimate exposure to SHS. Total number of subjects included in the study was 24,791. Those who self-reported not having used any tobacco products during the last five days were considered nonsmokers for the purpose of this study. Serum cotinine levels were used as the outcome variable to indicate the level of exposure to SHS. Adjusted serum cotinine levels for those with no exposure to SHS, exposure to SHS at work only, exposure to SHS at home only, and exposure to SHS at home and work were 0.047 (0.044-0.050)n g/mL, 0.055 (0.047-0.064) ng/mL, 0.522 (0.401-0.678) ng/mL, and 0.485 (0.280-0.0840) ng/mL respectively. Public efforts to reduce exposure to SHS at home should be strengthened.