You might be surprised by the answer
Parliament passes plain tobacco packaging law, regulates vaping Second Opinion: Canada's fight with Big Tobacco is back on At the time, the industry argued that taxes were making cigarettes too expensive, forcing smokers onto the black market to buy cheaper cigarettes a contraband supply which the industry itself helped create
[26] on the other hand, only examined current e-cigarette use, without accounting for prior smoking history: had there been a significant association between e-cigarette use and onset of respiratory symptoms, it could be due to prior cigarette smoking, in which case adjusting for pack-years would be necessary (though not necessarily sufficient) to account for this [14]
then you have to show cause and effect
[1] The longer the puff duration the greater the amount of particles produced
On me, it fades rapidly and is almost entirely gone within 30 minutes