In some e-cigarette flavors. Look at the actual study [1] and you'll see the dangers are mainly limited to some buttery/fruity/nutty flavors. The fact that Diacetyl occurs at much higher concentrations in regular cigarettes goes unmentioned. 'Popcorn lung' disease occurred with workers who were exposed to enough Diacetyl vapor in a day as an e-cig 'smoker' would be in a month. Finally, I'll leave the conclusion of the UK Department of Health [2] : "E-cigarettes around 95% less harmful than tobacco estimates landmark review"
As indicated in the second link, the scaremongering of studies such as this one mislead smokers into thinking that e-cigarettes are about as dangerous as regular ones. The dangers are not equivalent, by a long shot. Every smoker that switches to e-cigs, as I did 3 years ago after a 20 year habit and three failed attempts to quit, is much better off. Haven't smoked a 'real' one since. I know at least 50 people with the same experience (anecdotal, I know, but still...).
As indicated in the second link, the scaremongering of studies such as this one mislead smokers into thinking that e-cigarettes are about as dangerous as regular ones. The dangers are not equivalent, by a long shot. Every smoker that switches to e-cigs, as I did 3 years ago after a 20 year habit and three failed attempts to quit, is much better off. Haven't smoked a 'real' one since. I know at least 50 people with the same experience (anecdotal, I know, but still...).
[1] http://ehp.niehs.nih.gov/wp-content/uploads/advpub/2015/12/e... [2] https://www.gov.uk/government/news/e-cigarettes-around-95-le...