There is no tobacco in vaping so vaping = 0 tobacco cigarettes. If you must.... For my e-juices to = 400 cigarettes worth of nicotine or averaging 4800mg of nicotine (12mg per cigarette worth of nicotine), I would need to vape 800 mls of e-juice in 20 days. This takes me 7 months. To = 1 pack of cigarettes worth of nicotine I need to vape 40 mls or 8 days of me vaping.  When I was a smoker 400 cigarettes would take me 20 days to smoke. This is 7357 chemicals per tobacco cigarette. This is 147,140 chemicals per pack of cigarettes not going into my body.  2,942,800 chemicals over 400 cigarettes. The average nicotine vape has under 5% and the cancer risks of a .5% of the chemicals which most can't be distinguished from the air we currently breathe in having more cancer risks. I would need to vape 8018 mls of e-juice 70 months or almost 6 years of vaping to = 20 packs of tobacco cigarettes of chemicals. This is the very definition of harm reduction. No study to show proof of your argument... You need vaping facts. 1 is a short easy read with studies linked in blue writing.... study 2 is everything in study one but longer and more science involved. 3 is vape vs cigarettes      1)    2)  3)