To compare air nicotine concentrations according to the smoking policy selected by bars/restaurants in Santiago, Chile before and after the enactment of partial smoking ban legislation in 2007 (establishments could be smoke free, have segregated (mixed) smoking and non-smoking areas, or allow smoking in all areas). The study measured air nicotine concentrations over 7 days to characterise secondhand smoke exposure in 30 bars/restaurants in 2008. Owner/manager interviews and physical inspections were conducted. Median IQR air nicotine concentrations measured in all venues were 4.38 (0.61-13.62) μg/m(3). Air nicotine concentrations were higher in bars (median 7.22, IQR 2.48-15.64 μg/m(3)) compared to restaurants (1.12, 0.15-9.22 μg/m(3)). By smoking status, nicotine concentrations were higher in smoking venues (13.46, 5.31-16.87 μg/m(3)), followed by smoking areas in mixed venues (9.22, 5.09-14.90 μg/m(3)) and non-smoking areas in mixed venues (0.99, 0.19-1.27 μg/m(3)). Air nicotine con
