Is secondhand vapor a risk to bystanders?
I’ll save you some trouble if you haven’t guessed already. The answer is no, there is no evidence at all that suggests any risk to bystanders from secondhand vapor, or aerosol, which is the technical description of what is inhaled and exhaled from an e-cigarette.
No legitimate scientist who’s looked at this has come up with anything concrete they can pin on vapor. Oh, there’s some mights and maybes, but there always are in science — and especially in this science.
The first and still best look at “passive vaping” was “Peering Through the Mist,” a systematic literature review by Drexel University’s Igor Burstyn. This study was actually crowd-funded by CASAA. Burstyn extracted over 9,000 observations on e-cig vapor from the literature using a PubMed search, and evaluated the findings.
He attempted to “estimate potential exposures from aerosols produced by electronic cigarettes and compare those potential exposures to occupational exposure standards.” The goal was to look at passive vapor exposure the same way occupational exposure standards are created — assuming that bystanders were unwilling to assume any risk (as opposed to vapers, who probably would be).
He concluded that there was very little risk to vapers, but that the science on inhalation of PG or VG might change — or, more precisely, that risks from those products might emerge — and create some small future exposure risk. That’s for vapers though, not bystanders.
“Exposures of bystanders are likely to be orders of magnitude less, and thus pose no apparent concern.”
“Current state of knowledge about chemistry of liquids and aerosols associated with electronic cigarettes indicates that there is no evidence that vaping produces inhalable exposures to contaminants of the aerosol that would warrant health concerns by the standards that are used to ensure safety of workplaces,” Burstyn wrote. “However, the aerosol generated during vaping as a whole (contaminants plus declared ingredients) creates personal exposures that would justify surveillance of health among exposed persons in conjunction with investigation of means to keep any adverse health effects as low as reasonably achievable. Exposures of bystanders are likely to be orders of magnitude less, and thus pose no apparent concern.”
That last line is exactly what this article is concerned with. We can summarize his conclusion like this: there is very little for vapers themselves to worry about in vapor, and 10 times, 100 times, or maybe even 1,000 times less for people breathing passive secondhand vapor.
The Royal College of Physicians and Public Health England
The most famous review of available e-cigarette literature, “Nicotine Without Smoke” from the Royal College of Physicians, disposed of the secondhand vapor issue quickly. “Users of e-cigarettes exhale the vapour, which may therefore be inhaled by others, leading to passive exposure to nicotine. There is, so far, no direct evidence that such passive exposure is likely to cause significant harm, although one study has reported levels of polycyclic aromatic hydrocarbons that were outside defined safe-exposure limits. It is clear that passive exposure will vary according to fluid, device and the manner in which it is used. Nicotine from exhaled vapour can be deposited on surfaces, but at such low levels that there is no plausible mechanism by which such deposits could enter the body at doses that would cause physical harm.”
Despite what the paranoid proponents of denormalization say, there is no vape smoke.
Likewise, the first major report on vaping — “E-cigarettes: an evidence update,” commissioned by Public Health England — found no cause for alarm, and mainly considered the issue of passive nicotine exposure.
“Four studies examined nicotine exposure from passive vaping. [Long et al] measured nicotine content of EC [e-cigarette] exhalations,” they wrote. “EC exhalations contained eight times less nicotine than cigarette exhalations. Estimating environmental nicotine exposure, however, has to take into account the fact that side-stream smoke (ie the smoke from the lighted end of the cigarette, which is produced regardless of whether the smoker is puffing or not) accounts for some 85% of passive smoking and there is no side-stream EC vapour. A study measuring nicotine residue on surfaces in houses of smokers and vapers reported only negligible levels from vaping, 169 times lower than from smoking.”.
There have been several studies funded by manufacturers, like this one from Imperial Tobacco’s Fontem Ventures. The findings have shown that because e-cig vapor dissipates quickly, breathing it passively poses very little risk, if any.
In a study by the Spanish Council of Scientific Research, researchers compared cigarette smoke and e-cig vapor for 156 volatile organic compounds (VOC’s), and found nothing of concern. As Dr. Konstantinos Farsalinos wrote, “The results of the study basically showed that indoor air and normal exhaled breath contains more VOCs that the e-cigarette aerosol!”
In a 2013 study, a team of American and Polish scientists, including Maciej Goniewicz of the Roswell Park Cancer Institute, measured nicotine, aerosol particles, carbon monoxide, and VOC’s emitted by various e-cigarettes. They also found some passive exposure to nicotine — 10 times lower than from cigarette smoke — but nothing else to raise concern. “Using an e-cigarette in indoor environments may involuntarily expose nonusers to nicotine but not to toxic tobacco-specific combustion products,” they concluded.