How widespread is electronic cigarette use in outdoor settings? A field check from the TackSHS project in 11 European countries.

Exposure to secondhand aerosol from electronic cigarettes (e-cigarettes) may pose harms to bystanders, but they are used in many indoor settings. Less evidence exists on e-cigarette use in outdoor settings. This study aims to assess the use of e-cigarettes in outdoor settings in Europe. A cross-sectional study was conducted at the entrances of primary schools (N=200), children's playgrounds (N=200), and outdoor hospitality venues (N=220) during 2017-2018 in major cities of 11 European countries. We performed 30-minute observations and recorded e-cigarette use at three-time points: at 0 minutes, 15 minutes, and 30 minutes. We described the number and proportion of settings with e-cigarette use observed at any of the three-time points according to country and other contextual variables. Results showed that there were 22 (11.0%) school entrances, eight (4.0%) playgrounds, and 47 (21.3%) outdoor hospitality venues where e-cigarette use was observed at any time point. School entrances and outdoor hospitality venues with observed e-cigarette use were more frequently found in countries with a higher prevalence (>1.4%) of e-cigarette use (school entrances: 18.0% vs. 4.0%; p=0.002, outdoor hospitality venues: 26.7% vs. 15.0%, p=0.036). In conclusion, the outdoor setting with the highest visibility of e-cigarette use was outdoor areas of hospitality venues. Although still limited, e-cigarettes were also used in outdoor settings frequented by children. Governments should consider measures to restrict e-cigarette use outdoors to protect the health of bystanders, particularly in areas where children may be present.