Because e-cigarettes have only been available in the United States and Europe for a little over a decade, we don’t fully understand the long-term effects of vaping on users.
However, we do know enough about the likely health risks of vaping—based on the safety profiles of the chemicals involved—to understand that vaping almost certainly doesn’t pose risks to users as great as those of combustible cigarettes.
We may actually know more about the risks to bystanders than to vapers themselves. Based on standards for workplace exposure to inhaled chemicals and metals, scientists can estimate whether the toxic constituents present in “secondhand vapor” might make vaping harmful to “accidental vapers.”
So far, there’s no evidence that secondhand (or passive) vaping is a serious threat to the health of non-vaping bystanders.
Secondhand vapor (which is technically an aerosol) is the vapor exhaled into the atmosphere by an e-cig user. Like secondhand smoke, it lingers in the air long enough that anyone in the same room (assuming the room is small enough) is likely to inhale some of the exhaled aerosol. As the name indicates, the bystanders are not inhaling secondhand (or passive) smoke—because secondhand e-cigarette vapor simply isn’t smoke.
Smoke is a product of combustion. Burning any substance with fire—including wood, leaves, a building, or any plant material, including tobacco—produces volatile gasses, carcinogenic solid particles, carbon monoxide, and a mixture of dangerous byproducts that in cigarette smoke is called tar. Secondhand smoke isn’t as dangerous as inhaling directly from a cigarette, but regular and prolonged exposure to it is considered a serious hazard.
E-cigs heat e-liquid with a small metal coil housed in an atomizer, and the heat turns the e-juice into the vapor you see. E-cigarette vapor doesn’t have any carbon monoxide or tar, and the particles in the aerosol are liquid rather than solid. Dangerous chemicals and metals are found in vapor, but only in tiny quantities. The levels of toxicants are minute compared to those found in smoke, which means the dangers of secondhand vaping are less significant.
If you encounter people vaping inside a house, all of the secondhand vapor you see comes out of the mouths of the vapers in the room. There is no side stream “vape smoke” like there is side stream tobacco smoke from cigarettes—no constant emission of vapor pouring from the device when it’s not being used. The user has to inhale to produce vapor. And by the time the vaper exhales, the vapor contains much less of all the substances that were in the inhaled vapor, because most of it is absorbed by the user’s mouth, throat and lungs. There simply aren’t enough of the already-scarce toxicants left over to make secondhand vapor a concern.
Aside from propylene glycol and glycerin (PG and VG)—the two glycols that make up the base of virtually all e-liquids—what vapers exhale into the air doesn’t contain high levels of anything. According to Drexel University toxicologist Igor Burstyn, while the contents of e-cig vapor inhaled by users “justifies surveillance,” there is so little contamination in exhaled vapor that there is unlikely to be any risk for bystanders.
What isn’t inhaled falls to the ground quite rapidly. Those concerned with “thirdhand nicotine”—the unabsorbed nicotine that lands on floors and furniture—might make a case for not vaping around kids or pets who might lick the surfaces. But there’s not much nicotine left in the settled residue. According to a 2016 University of California-San Francisco study, 93.8 percent of the inhaled nicotine is retained by the user, and is not part of the exhaled vapor.
“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,” Royal College of Physicians researchers noted in that organization’s comprehensive 2016 review of e-cigarette science.
Particles from vaping, which are liquid rather than solid like smoke particles, don’t seem to affect air quality at all. In a 2017 University of California-San Diego study that analyzed the air in 193 low-income family homes, the researchers found that smoking tobacco or marijuana, cooking, and burning candles all affected particle counts in the homes. But vaping (which was being done in 43 of the homes) had no measurable effect on the indoor air quality.
Even studies of the air in vape shops have shown that levels of toxicants are below occupational exposure limits. In fact, the National Institute for Occupational Safety and Health (NIOSH—a CDC agency) found that even in a shop where 13 customers vaped during the day, the flavoring chemicals and formaldehyde measured in the air were all below the allowable exposure limits, and nicotine was practically absent from the samples.
In Public Health England’s updated 2018 evidence review, the agency’s experts analyzed several new studies of passive exposure that had been published since the original 2015 PHE e-cig report. They concluded—again—that “to date there have been no identified health risks of passive vaping to bystanders.”
Igor Burstyn’s study of the possible dangers of secondhand vaping attempted to “estimate potential exposures from aerosols produced by electronic cigarettes and compare those potential exposures to occupational exposure standards.” His conclusion: “Exposures of bystanders are likely to be orders of magnitude less, and thus pose no apparent concern.”
Orders of magnitude are multiples of 10. Therefore, 10, 100, 1,000, 10,000, and so on. What Burstyn means is that the exposure to toxic chemicals in secondhand vapor is so slight as to pose no real threat. Whatever the risk may be to the users themselves, it is 10 or 100, or even 1,000 or 10,000, times lower for the bystander.
Does that necessarily mean that vapers should feel free to vape everywhere without regard to the wishes of others? No!
Even if secondhand vaping can’t be proven harmful to others, the concerns of family and friends need to be respected. Obviously, if a spouse or visitor objects, vapers should be courteous and thoughtful, and take the vape outside. Clearly, if someone in the home has asthma or another respiratory condition, secondhand vape is best avoided, since we know PG and some flavorings can irritate the airways.
Children, of course, don’t get to make an informed choice about what they breathe, so vapers should use good judgement and be more cautious than they might be around adults. There are no secondhand vapor studies that specifically measure the lung functions of babies or young children after daily vape inhalation. Vapers shouldn’t experiment on their kids.
Thanks for the informative article. And especially thanks to the smart folks who invented vaping. I was dumb enough to start smoking when I was a teenager. Kept at it for over 20 years, and failed at quitting I don’t know how many times. Decided to grab an e-cig finally a while back once the technology started getting good, and it was one of the best moves I’ve ever made. Started out with a high nicotine liquid and slowly tapered down to no nicotine liquid. Stuck with that for a bit, and one day forgot my vape when I went… Read more »
I found this very useful! Thanks for taking the time to write this.
Reading the comments on this article was one laugh riot after another. It’s interesting to see how people react to an article citing facts as a tool for enabling addicts. I’m sorry to say, but if you’re related to or involved with someone who Vapes and they site articles like this to undermine you when you voice your discomfort, that particular vaper is a dick. But the reality is that while that vaper may be being an ass, that doesn’t invalidate what they’re saying or by extent the information source they’re using. Trying to correlate unrelated illnesses with the onset… Read more »
The article is biased and minimizes the negative effects of vaping to the vaporer & by stander. That stuff is dangerous!
Can you name some of the dangers—without using hypotheticals?
The only thing I hear from that last commenter is crickets. I’m sire they’re just gathering facts.
Also, in the spirit of lacking….add reading comprehension to your list
I am writing an essay on vaping versus cigarette smoking. How can I cite the information I’ve gotten from this article?
If you’re citing what I wrote, use quotes and attribute it to me. If you’re using the studies that are linked, attribute to those authors. Is that what you’re asking?
I’ll tell you what. The tobacco industry is very interested in vaping profits now. The vaping industry better get together, form a coalition against big tobacco ever getting further in the game, and hire some lobbyists. On another note, prices of vape juice(often the same exact brands and flavors) vary from $13-$20 and some up to $45 for 120ml bottles. At least two of those sites force you to accept one shipper that costs $8.50- $10 for 2-4 business-day shipping. And speaking from personal exp. they didn’t even ship mine til about 4 days after my order and that’s when… Read more »