Objective: To quantify environmental tobacco smoke exposure in public places in Mexico to promote policies of 100% smoke-free environments.
Materials and methods: In hospitals, schools and public offices of Monterrey, Guadalajara and Mexico City 20% of inner areas were monitored. Median nicotine concentrations were estimated by city, type of public space and type of inner area.
Results: Median concentration in areas where nicotine was detected was 0.06 µg/m³ (P₂₅=0.03, P₇₅=0.12 µg/m³). Higher concentrations were found in Mexico City and in public offices. Nicotine was not detected in 75% of monitored areas.
Conclusions: Monitoring environmental nicotine is a useful tool to evaluate compliance of public places with the smoke-free environments legislation, and could constitute an important source of information to strengthen implementation efforts.