Second-hand smoke exposure in indoor and outdoor areas of cafés and restaurants: Need for extending smoking regulation outdoors?

Smoke-free legislation in indoor public places has concentrated smokers in the are as outside building entrances or other outdoor areas. This study assessed the drift of second-hand smoke between outdoor and indoor areas of cafés and restaurants in Barcelona,Spain, and characterized the exposure on outdoor terraces. Using a cross- sectional design,we monitored vapor-phase nicotine in indoor areas and outside entrances simultaneously (n¼47), and on some outdoor terraces(n¼51). We computed the median nicotine concentration and inter-quartile range (IQR) to describe the data and performed multivariate analysis to describe nicotine concentration and its determinants. The overall median nicotine concentration indoors was 0.65 mg/m3 (IQR:0.29–1.17 mg/m3), with significant differences based on the number of smokers at the entrance (p¼0.039). At outside entrances, the overall median nicotine concentration was 0.41 mg/m3 (IQR:0.21–1.17 mg/m3). The nicotine concentrations indoors and at the corresponding outside entrances were not significantly different, and the multivariate analysis confirmed the relationship between these variables.