Objective To examine the status and influencing factors of exposure to second-hand smoke (SHS) among 15 – 69 years old residents in Guangzhou city for providing evidences to tobacco control.

Methods Using stratified multistage random cluster sampling, we selected 4 063 permanent residents aged 15 – 69 years in 11 districts across Guangzhou city for a household questionnaire survey about SHS between August and December 2018.

Results Of the nonsmoking participants, 60.1% (1 928/3 210) reported exposure to SHS and 45.0% (868/1 928) of the SHS exposed nonsmoking participants reported SHS exposure at the frequency of 1 – 3 days/per week; the reported prevalence rate of SHS exposure differed significantly by age group, gender, education, occupation, and registered residence (all P < 0.05). Significantly higher rates of awareness about tobacco hazards and no smoking at home were reported by participants not exposed to SHS compared to those reported by SHS exposed participants (both P < 0.05), but only for the cognitions on the hazards of low tar cigarette smoking, no smoke of some cigarette with less hazard to health, and household smoking. The results of unconditional logistic regression analyses revealed that with household smoking and with a household registration of Guangzhou city were risk factors for SHS exposure; while the cognition on the hazards of low tar cigarette smoking being not less than that of common cigarette smoking and being a teacher or a student were protective factor against SHS exposure.

Conclusion The prevalence of second-hand smoke exposure is high but the knowledge rate of tobacco hazards is relatively low among adult residents in Guangzhou city, suggesting that regulations and health education on tobacco control should be promoted among the residents, especially among the key population, in the city.