This is what I think.
Just because I can't see or smell the nicotine vapor these E-cigarettes use .
It doesn't mean they are not producing second hand vapor .
Both from the E-cigarette itself & the "smoker" when they breath it out.
In that I doubt the vapor is 100% absorbed.
So I don't want to breathe that either.
For those that use E-cigarettes . Use them outside just like they were regular cigarettes.
The E-cigarettes are to new to have data on the long term effects of nicotine . It might be a carcinogen as well . It is probably not as bad a tar & other resins ,chemicals in tobacco . So should be some better healthwise.
To those that are smokers an article several years ago that said the sugars used in processing tobacco were carcinogen . Burned sugars are apparently bad for a smoker. Also that cancer rates for smokers were much lower in countries where tobacco wasn't sugar cured.