There are two principal lines of reasoning behind bans on vaping in public places. For one thing, public health officials are committed to limiting the proliferation of vaping, and if that means limiting its visibility by restricting the rights of current vapers, then so be it. For another thing, the same group has also expressed worries about the effects of “second-hand vaping,” a murky concept at best. Worries about second-hand vaping, for example, lie at the basis of Ontario’s new ban on vaping in cars with children under 16.

Studies on the topic of second-hand vaping used to be extremely difficult to come by, but with the upsurge of vaping over the past year, the research landscape has shifted rapidly. Over the past couple of months or so, for example, two studies on second-hand vaping have been published in academic journals. As you might have expected, both of these studies showed that worries about second-hand vaping are basically groundless.

The first study, which looked at nicotine residues in the homes of smokers, vapers, and people who neither vape nor smoke, found that, while nicotine residue levels in smoking households were extremely high, with an average of 1303 ± 2676 μg/m2, differences in surface nicotine levels between vaping households and non-smoking/non-vaping homes were not statistically significant. Compared to the smoking homes’ levels of surface nicotine, the 7.7 ± 17.2 μg/m2 average of surface nicotine is practically nothing. The study was conducted by researchers at the Roswell Park Cancer Institute in Buffalo, New York.

The second study looked at indoor air quality in a room in which five test subjects, three of whom were experienced vapers, vaped during a simulated business meeting in order to get a good sense of air nicotine levels under conditions of normal use. While the study did show that propylene glycol levels in the air shot up while the occupants were vaping, researchers found that air nicotine levels remained unchanged. And despite the rapid increase in propylene glycol levels, these levels remained far, far below than UK Workplace Exposure Limit guidelines (0.203 mg/m3 v. 474 mg/m3), and also dissipated rapidly. Vaping basically just appears to briefly increase propylene glycol levels in ambient air under conditions of normal use, while having no noticeable effect on ambient nicotine levels. Second-hand vaping, apparently, only results in super-mild propylene glycol exposure.

As usual, the provenance of this second study might raise some eyebrows. The principal researchers involved in this study are employed by Imperial Tobacco, and thus we should approach their methods with an extra degree of scrutiny. On the other hand, it’s important to keep in mind that researchers, even those who work for a big tobacco company, are highly unlikely to falsify their findings. Usually, biased studies are primarily biased in their experimental design; as long as the experimental design is sound, though, the results can presumably be trusted. In this case, the experimental setup seems quite reasonable. In fact, it seems a lot more reasonable than most studies on vaping, in which researchers have largely ignored natural vaping conditions in order to fabricate their negative findings. And given that both of these studies agree in their findings that second-hand vaping poses basically no danger, I think these results can probably be trusted.

Happy vaping!