The study, performed by the Spanish Council of Scientific Research, measured the levels of volatile organic compounds (VOCs) exhaled by people who inhaled air, compared to people who inhaled tobacco smoke and people who inhaled electronic cigarette vapour.
‘Volatile organic compounds’ can be a misleading term, as it refers to a large number of compounds some (but not all) of which can be toxic. The study in question measured 156 compounds.
It was found that the levels of these compounds exhaled by vapers was far lower than the amount exhaled by smokers, with a large number of them being marked ‘ND’ or ‘Not Detected’.
That means that a majority of the compounds found in second-hand smoke are simply not present in exhaled vapour. The study also indicated that the compounds which were detected in the vapour were at such low concentrations as to be totally harmless.
Interestingly, the study also found that exhaled electronic cigarette vapour had lower concentrations of certain compounds than exhaled air.
E-cig vapour, then, seems to contain fewer VOCs than not just second-hand smoke, but also the air exhaled by a non-smoker and –vaper.
Table by Dr. Farsalinos from https://www.ecigarette-research.org/research/index.php/whats-new/whatsnew-2015/226-sp
Basically this table shows that second-hand vapour contains so few VOCs as to make it totally harmless. Even nicotine, which will obviously be present in the exhaled vapour, is present at such low concentrations that, in the words of Dr. Farsalinos of ecigarette-research.org, “the amount of nicotine in the environment is so low that it does not have any effect (not even a biological effect, let alone an adverse effect) on those environmentally-exposed.”