A cross-sectional study on levels of secondhand smoke in restaurants and bars in five cities in China

Objectives To assess indoor secondhand smoke (SHS) exposure in restaurants and bars via PM2.5 level measurements in five cities in China. Methods The study was conducted from July to September in 2007 in Beijing, Xi'an, Wuhan, Kunming and Guiyang. PM2.5 concentrations were measured in 404 restaurants and bars using portable aerosol monitors. The occupant density and the active smoker density were calculated for each venue sampled. Results Among the 404 surveyed venues, 23 had complete smoking bans, nine had partial smoking bans and 313 (77.5%) had smoking observed during sampling. The geometric mean of indoor PM2.5 levels in venues with smoking observed was 208 μg/m3 and 99 μg/m3 in venues without smoking observed. When outdoor PM2.5 levels were adjusted, indoor PM2.5 levels in venues with smoking observed were consistently significantly higher than those in venues without smoking observed (F=80.49, p<0.001). Indoor PM2.5 levels were positively correlated with outdoor PM2.5 levels (partial ρ=0.37 p<0.001) and active smoker density (partial ρ=0.34, p<0.001). Conclusions Consistent with findings in other countries, PM2.5 levels in smoking places are significantly higher than those in smoke-free places and are strongly related to the number and density of active smokers. These findings document the high levels of SHS in hospitality venues in China and point to the urgent need for comprehensive smoke-free laws in China to protect the public from SHS hazards, as called for in Article 8 of the Framework Convention on Tobacco Control, which was ratified by China in 2005.