According to experts e-cigarrettes are far more less harmful than tobacco cigarette
https://www.gov.uk/government/news/e-cigarettes-around-95-less-harmful-than-tobacco-estimates-landmark-review
Also new research proofs that inhaling vapor is similar to inhaling air http://www.mirror.co.uk/news/technology-science/technology/e-cigarette-vapour-no-toxic-effect-6072036
Passive vaping has no imminent effect to by-standers or biological effect what so ever. The cotinine levels are almost non-excistent http://www.ecigarette-research.com/web/index.php/2013-04-07-09-50-07/2014/184-
An adult person should have right to use nicotine in any way they want. If it was snus, gum, patches, tobacco or electronic cigarette.
It is our right to vape.