Current research shows that there is little evidence to suggest that e-cigarette vapour is harmful to non e-cigarette users. Professor John Britton and Dr Ilze Bogdanovica, from the UK Centre for Tobacco and Alcohol Control Studies, in a report commissioned by the Public Health England summarised the current knowledge by saying:
"Electronic cigarettes do not produce smoke so the well-documented effects of passive exposure of others to cigarette smoke are clearly not relevant. Exposure of non smokers to electronic cigarette vapour poses a concern, though laboratory work suggests that electronic cigarette use in an enclosed space exposes others to nicotine at levels about one tenth generated by a cigarette, but little else. The health risks of passive exposure to electronic cigarette vapour are therefore likely to be extremely low."