December 21, 2018

Is Second Hand Vapor Harmful to Breathe?

Vaping is a fairly new phenomenon. Electronic cigarettes have only been available in the U.S. and Europe for about a decade, and that means we don’t fully understand the long-term effects of vaping on users. However, we do know enough about the likely risks of vaping and health — based on the safety profiles of the chemicals involved — to understand that vaping is highly unlikely to pose risks to users as great as those of combustible cigarettes.

And we actually know more about the risks of vaping to bystanders. That’s because there are standards for measuring “environmental exposure” (the risk of breathing chemicals in the air) that can be applied to e-cig vapor.

Based on government standards for workplace exposure to inhaled chemicals and metals, scientists can estimate whether the toxic constituents present in “second hand vapor” might make vaping harmful to others. And so far, there’s no evidence that second hand vaping is a serious threat to the health of non-vaping bystanders.

What is second hand vapor?

Second hand vapor is the vapor (which is technically aerosol) exhaled into the atmosphere by a vaper. Like second hand smoke, it lingers in the air long enough that anyone in the same room, assuming it’s small enough, is likely to inhale some of the exhaled aerosol. As the name indicates, the bystanders are not inhaling second hand smoke — because second hand e-cigarette vapor simply isn’t smoke.

Smoke is a product of combustion. Burning any substance with fire — including wood, leaves, a building, or tobacco — produces volatile gasses, carcinogenic particles, carbon monoxide, and a mixture of dangerous byproducts that in cigarette smoke are called tar. Second hand smoke isn’t as dangerous as inhaling directly from a cigarette, but prolonged exposure to it is considered a serious hazard.

Vapers produce clouds of vapor by heating e-liquid with an atomizer that houses a small metal coil, which turns it into the vapor you see. The vapor from e-cigs doesn’t have any carbon monoxide or tar. Dangerous chemicals and metals are found in vapor, but in very small amounts. The levels of toxicants are tiny compared to those in smoke, which means the dangers of second hand vaping are even less significant.

What's in second hand vapor?

If you encounter people vaping inside a house, all of the second hand vapor you see comes out of the lungs and mouths of the vapers in the room. There is no side stream “vape smoke,” like there is with cigarettes — no constant emission of vapor pouring from the device. The vaper has to inhale to produce vapor. And by the time they exhale, there’s a lot less of all the substances found in the vapor, because the users absorb most of it in their lungs, throats, and mouths. Vaping second hand isn’t really a thing, because the bystanders are getting so little of the contents of the vape.

Aside from propylene glycol and glycerin — the two glycols that together make the base of all e-liquids — what vapers exhale into the air doesn’t contain high levels of anything. According to Drexel University toxicology expert 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.

What isn’t inhaled falls to the ground. Those concerned with “third-hand 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,” said the Royal College of Physicians in its 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 studied the air in 193 low-income family homes, the researchers found that smoking of tobacco and marijuana, cooking, and burning candles all affected particle counts in the homes. But vaping (which happened in 43 of the homes) had no measurable effect on the indoor air quality.

Even second hand vape 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 were all below the limits allowed. And nicotine was practically absent from NIOSH’s samples.

Is second hand vapor dangerous?

Looking at the vaping studies mentioned above and others, Public Health England’s 264-page review of available evidence of vaping risks concluded that “to date there have been no identified health risks of passive vaping to bystanders.”

Igor Burstyn’s study of the dangers of second hand vaping attempted to “estimate potential exposures from aerosols produced by electronic cigarettes and compare those potential exposures to occupational exposure standards.” He concluded that “Exposures of bystanders are likely to be orders of magnitude less, and thus pose no apparent concern.”

Orders of magnitude are multiples of 10 — so, 10-100-1,000-10,000 and so on. What Burstyn means is that the exposure to toxic chemicals in second hand vapor is so slight as to pose no real threat. Whatever the risk to the vaper, it is 10 times, or 100 times, 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 second hand 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 a resident of the home has asthma, second hand vape is best avoided, since we know PG and some flavorings can irritate the airways.

And, of course, children don’t get to make an informed choice about what they breathe, so vapers should use their best judgement and probably be more cautious than they would around adults. There are no second hand vapor studies that specifically measure the lung functions of babies or young children after heavy daily vape inhalation. Vapers shouldn’t experiment on their kids.

Smokers created vaping without any help from the tobacco industry or anti-smoking crusaders, and vapers have the right to keep innovating to help themselves. My goal is to provide clear, honest information about the challenges vaping faces from lawmakers, regulators, and brokers of disinformation. I recently joined the CASAA board, but my opinions aren’t necessarily CASAA’s, and vice versa. You can find me on Twitter @whycherrywhy

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I have had no lung problems for ages, but recently I have been staying with my daughter who vapes and this morning I went to the doctor complaining of severe coughing and wheezing. Asmatic attacks. I am having severe problems breathing and tired. The doctor has prescribed me 2 inhalers, as I can hardly speak. Antibiotics because they think I have a chest infections also. So I was also wondering if the vaping was affecting me. It’s interesting to hear similar stories. Last night I felt very light headed also.

Jim McDonald

I’m confused. You say you’ve had asthmatic attacks, but don’t say you have asthma (you can’t have such attacks with having asthma). If you have asthma, that’s probably the source of your issues. According to the Mayo Clinic, these are the most common triggers for asthma attacks:

Pollen, pets, mold and dust mites

Upper respiratory infections

Tobacco smoke

Inhaling cold, dry air

Gastroesophageal reflux disease (GERD)


If you have a bacterial infection (thus the prescribed antibiotics), that is probably the source of your problems, either directly or by triggering your existing asthma.

It sounds like your doctor — who certainly knows better than a vaping website — has narrowed the potential causes of your breathing problems to two very likely sources. Are you asking if breathing secondhand vapor is a better explanation than having both asthma and a respiratory infection?



My mom is elderly and has been vaping for the past several years. This has kept her off the cigs and I believe that is a good thing.
My issue is that I feel affected by the second-hand “smoke” from her vape. It irritates my throat and lungs and makes me feel slightly nauseous.
I am frustrated because I can’t seem to find any information online to corroborate my experience. I don’t want to be an anti-smoking tyrant, but it’s hard to discuss this with her as I don’t have any information to support my experience. I think she believes I’m being hypersensitive.
Do you have any information in this regard?

Thank you

Jim McDonald

You may have a sensitivity to either PG or VG — or to one of the flavorings in your mother’s e-liquid. An allergist can test for that. More likely, the vapor in the enclosed space is just kind of gross to smell. If she’s using high-VG liquid, it produces more and thicker vapor than 50/50 or high-PG liquid. If she’s using the same flavor all the time, maybe a change of flavors will help. Or maybe your mom could vape just in certain rooms that have ventilation (like a window fan blowing out). Good luck, and thanks for being understanding.


I am writing an essay on vaping versus cigarette smoking. How can I cite the information I’ve gotten from this article?

Thank you.

Jim McDonald

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 would very much like to use this article to share with my neighbors at a community meeting as several folks, who don’t know much about vaping are concerned with second hand harm. I hope that’s ok?

Jim McDonald

It’s okay, but here’s a word of warning: anyone who is already skeptical about vaping will probably not be convinced by an article in a vaping publication. You would be much better off taking the original studies mentioned in the article, which are from more trusted sources.


I found this very useful! Thanks for taking the time to write this.


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 out with a friend. Thought it was silly how bad I was fiending for my vape when I didn’t have it so I decided to not pick it back up and to see what happens. Within a few days I wasn’t even thinking about it anymore. E-cig helped me quit smoking and probably extended my life by decades.

I think complaints about second hand vapor are interesting. Especially when you consider the fact that wood smoke from a camp fire or fireplace (which most folks don’t tend to complain about) is somewhere between 7 and 30 times more harmful than cigarette smoke, and if e-cig vapor is orders of magnitude less harmful than that… Well, it’s pretty much a non-issue. There’s so much crap in our atmosphere already, from the cars we drive, the planes we fly in, the power plants that provide our electricity, the grills we barbecue with… The quickly-dissipating vapor from e-cigs is so incredibly innocuous compared to all that. It’s pretty silly that people get miffed about it really. I feel for those who have allergies to PG or any of the other few chemicals in vapor, but I also feel for people with egg, peanut, and latex allergies. Some things are hard to avoid. I have some allergies myself. But oh well. I’d be willing to endure a little irritation if I know the thing that’s irritating me is helping to drastically improve the health and probably save the life of the people using it. Bring it on.

Smoking is a very difficult beast to defeat once it gets its claws in you. E-cigs are a freaking godsend weapon against that beast as far as I’m concerned.


My husband started vaping 11 years ago to help him “quit” smoking. He no longer smokes cigarettes, but now he constantly breathes through his e-cigarettes. He smokes way more now, than he did with cigarettes. At least with cigarettes there was more of a conscious decision being made to light up a cigarette and when the cigarette was done, it was done, unless you made the conscious decision to light up another one. With e-cigarettes, it’s more of a subconscious habit. You can puff away until you run out of juice, which takes way longer than any cigarette! My main problem with it is he vapes in the house and around the kids. I know you said you should just ask people that are vaping to not vape around you, but it’s not always that easy because people that vape don’t think there is any harm to those around them. This has turned into a huge debate. I just feel there hasn’t been enough time that has passed to fully understand all the risks, especially to children. I can tell you the windows in our house and cars get the most awful film on them. It’s disgusting! It looks like it’s constantly foggy outside. If that’s sitting on our windows, what kind of gunk are we breathing in?

Jim McDonald

I’m not sure what to tell you at this point. The fact is, vaping is NOT smoking; there’s no combustion and no proven dangers. However, I probably wouldn’t want to vape in the house if I had children, or a wife who objected to it. I wish for your sake that your husband was willing to compromise. As for the windows, the guy blowing the clouds in the house ought to be grabbing the Windex regularly and taking care of that.


Just curious, why wouldn’t you vape in a house with children? As you mentioned, it isn’t harmful, right? The problem with people that rely on nicotine, is they are addicted and when you make ultimatums with their addiction, sometimes it doesn’t go well, even if it is something as simple as asking them not to vape around their children. Also, another problem is there are so many people and articles that are supporting their stance that there is no harm in the vapor and therefore those that are asking them not to vape are being ridiculous. I just feel there hasn’t been enough time to fully understand the exposure to vapor and I don’t think people or articles should be giving anyone a false sense of power or security. If you wouldn’t vape around kids, then don’t empower addicts.

Jim McDonald

I wouldn’t because while vaping is much safer than smoking, it isn’t proven to be 100% “safe.” But I wouldn’t judge others who do vape in a home with children, since the odds it will cause serious issues are low. Most people cook with oils in their homes — which can be very harmful — yet we never think twice about it.

You throw around the words “addiction” and “addict” pretty easily. How do you define it? Does it include caffeine too — or video gaming, or sugar? Or is it just things that you have a moral objection to?


I’d say throwing around the term “moral objection” is a little stronger than me using the word addict. We all know nicotine is an addictive substance and I feel sorry for anyone battling that. And yes, I agree that addiction is not just limited to nicotine. Absolutely someone can be addicted to gaming, sugar and caffeine as addiction can be related to a substance, thing or activity. I don’t have a moral objection to smokers or vapors. If I did, I would not have married my husband. He started smoking when he was 14 and was a full-time smoker when we started dating. I didn’t have a problem with him smoking and he smoked outside. I also don’t have a problem with him vaping, I would just prefer it to be outside and not around the children. But my argument is that when I ask him or other friends that vape to not do it indoors or around the children, they will quote articles such as yours that downplay any potential risks and portray my requests as overreacting. As I said, we don’t know the full impact of vaping since it is relatively new, so why imply it is safe when we don’t know that 100%?

Jim McDonald

We’re updating this article. Maybe you’ll like the new version better. Keep an eye out.

Jim McDonald

Saying that there’s no evidence of absolute safety isn’t at all the same as saying it’s “safe.” And I find it difficult to believe that the opinions in a vaping publication carry more weight with your husband than your wishes.


We all know second hand smoke is no good for you. I can tell you i cant breathe after being in it for very little time. I also believe it is inconsiderate vaping in a room with a non vapor

Jim McDonald

Vaping anywhere that people object to it is inconsiderate. But vapor is not secondhand smoke. It seems like you’re confusing the two things.


I know by experience that the vape that my son and friends exhales does cause me to cough and it irritates my throat. I also know that it leaves a film on my vehicles windows. If it does this then I would say there is more to it than someone is saying. That also since they’ve been doing it they cough and my sons tonsils [are enlarged] but again no proof, but more research needs to be done before we lead many to the grave or serious medical conditions because of our ignorance.

Jim McDonald

Lots of research is being done. If your son has problems with his tonsils he should get that looked at by an ENT specialist. It’s not likely to be vaping-related, but could be a serious issue.


How can the vapor be better than smoking when you have to charge it? ALso second hand smoking- just because you can’t see the smoke doesn’t mean it can’t harm you. My bf is a vapor smoker and I’m concerned on his health. Any feedback will be appreciated..thank you

Jim McDonald

Michelle, you say “vapor smoker,” but you’re missing why vaping is safer. The reason cigarettes are so dangerous is the SMOKE, which is created by burning tobacco and contains tar and carbon monoxide that cause the lung and cardiovascular diseases that kill smokers. There’s no smoke in vapor, because there’s no combustion, and therefore no no tar and no CO.


My son has been smoking a vape now for Aprox 6 months. He smokes it outside or in the garage. He had smoked it in his room and bathroom a many times as well. Since he has started vaping, I developed a cough. Whenever I smell the vape juice it makes me cough. Maybe it’s the vape juice itself being vaped and exhaled through the smokeless vapor that is harmful. There are many chemicals in the vape juice. In this article you are focused on the exhaled smokeless vape rather than what may be causing the concern in some bystandards. I think that down the line it will come out that it’s the vapejuice itself, along with the added nicotine that’s causing the harm. I can’t imagine what it’s actually doing to the persons insides that is vaping it. My nephew started vaping, never had a problem before he started vaping and now has diabetes. The doctors told him to stop vaping and that Chemicals and nicotine are poison for our bodies.

Jim McDonald

I’m not going to try and unpack all of this. I’ll just say that many studies have shown no harmful constituents are found in vapor at levels that cause harm to vapers — and the amounts inhaled by bystanders are even lower. You may have some sensitivity to a flavoring in your son’s vapor, or to PG itself. Vaping doesn’t — and couldn’t — cause diabetes. Can you get me the name of the doctor who suggested it could? I’d like to call him and ask by what mechanism vaping would affect human blood sugar levels. There isn’t any that I’m aware of.


Sooo your just going to casually skirt over the the affects of nicotine exposure?

Jim McDonald

Is there some evidence that secondhand vapor contains enough nicotine to affect a bystander in any way?


I’m not saying that it is harming me in anyway. But my brother is a constant vaper. I do not smoke or vape or really care if my brother does it. But when I’m sitting next to him and he vapes the second the cloud passes by me my lungs instantly reject it and I start to choke. I don’t even get that from when a cigarette smoker or pot smoker smokes near me. What gives?

Jim McDonald

You may be sensitive to PG or to one of the flavorings. Tell him to quit blowing clouds at your face!


We hired a douchebag millennial who is basically an addict. He can’t go 5 minutes without vaping. Never even asked if it was allowed ….just started vaping at his desk, like a self-involved millennial would….. If he had indicated this in his interview, he would not have been hired.

Both my associate and I now have respiratory attacks, sinus issues, and bad headaches like I’ve never seen before, and can’t stop coughing. When we are away from him, no coughing!

Explain why any un-metabolized nicotine in his exhaled steam, wouldn’t be passed along to his neighbors?

Neither Juul (nor shill Jim McDonald) will not be there when your lung disease bills accumulate.


My sister inlaws friend vapors constantly. I cant even see through the cloud filled room. Here it is thanksgiving and my son is sleaping on the couch in a 12’×12′ t.v. room at my mother inlaws and she is vaping away with no consideration for others. Just very wrong to do

Jim McDonald

Considerations of possible harms nothwithstanding, this is just an example of terrible manners, and an irresponsible host. The owner of the home should simply ask her to vape outside, since she obviously doesn’t have the sense to do it herself.

Jim McDonald

Why don’t you tell him vaping isn’t allowed at work?

Your respiratory problems seem serious. I’d see a doctor. It sounds like your new colleague may be vaping something other than e-liquid.

A tiny amount of nicotine isn’t absorbed by the user. Unlike smoke, it dissipates very quickly, and doesn’t pose a risk for bystanders according to Drexel University toxicology expert Igor Burstyn.

If I’m a JUUL shill, I’m not very good at it.


I live near a school where dozens of kids use these devices. I have felt ill from this crap a number of times. This is bull that it wouldn’t harm other people, it harms me!! No I’m not a person that suffers from asthma, but this crap gets into my nose and lungs, makes me feel sick within ten minutes – it lasts for hours – and thats from one exposure. So anyone that believes its safe, you are absolutely wrong. If these kids want to take that risk, they can go do it somewhere else. WAKE UP PARENTS, WAKE UP TEACHERS, WAKE UP POLICE. Go ask a doctor, I’m sure they are seeing kids ill from this.

Jim McDonald

Perhaps you have a sensitivity to propylene glycol. If so, it’s a miracle you haven’t noticed it before, since it’s an ingredient in thousands of soaps, cosmetics, and food products.

I suspect with about 30 million users worldwide, any widespread illness caused by vaping would have long since been splashed all over the front page. It sounds like you have a very unusual issue with it.


propylene glycol, yes i try to avoid that due to skin irritation in products like shampoo, so i don’t imagine inhaling it would be good either.

Jim McDonald

Yeah, best to avoid if you have a known sensitivity.


My brother does it in a car with the window down, whereas MOST of the vapor exits through the window (he tries not to bother me it) yet the little bit that floats to me still manages to give me a headache. Seeing that this doesn’t happen any other time, and that I’m probably not allergic to my brother (please note my sarcasm), the secondhand vapor cloud is the only variable left to cause this effect. Sorry bud, but there’s no other explanation.

Jim McDonald

Some people are sensitive to certain flavorings or scents. For example, a lot of people have reactions to cologne or perfume. I think the bigger question here is why your brother can’t wait till your ride is finished to vape.


I’ve done that (thus why he rolls the window down now to make most of it exit the car) but it isn’t enough to make him stop entirely.


Given the nicotine factor in the specific flavour he chose, that makes a pretty obvious explanation as to why he does not wait – he’s addicted to it.

Jim McDonald

Maybe — or maybe if you asked him nicely, he’d put a hold on the vaping until you reached your destination.

TheDangerousOne Where there’s Smoke, there’s Fire?, Where there’s Vapor, there’s someone Cool ?

Jim McDonald



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 of vape use is like an anti-vaxer saying autism is caused by a vaccination. There’s a misinterpretation of facts to pigeonhole them into a specific opinion. In continuing to run with the anti-vaxer analogy — yes, the rate of autism being diagnosed did increase alongside the mandated use of vaccines in public schools. Because vaccines cause autism? No. Being that percentage of people have always had autism and the medical communities started being able to identify the depths and variety in the spectrum of that particular form of neruodivergence and diagnose it.

–In terms of second-hand pollutants Vaping may not be 100% safe with no consequences to bystanders. But! Neither is walking down the street in a densely populated area, sitting next to a campfire, being stuck in bumper to bumper traffic, cooking with a variety of oils, using particular cleaning solutions or other aerosol spray(s), and the list goes on.

Almost nothing we do today has absolutely no risk on our long-term health. We do not exist in a vacuum. And while vaping had remarkably less risk than many everyday things, you the individual are still allowed to decide if it makes you uncomfortable or not. And it’s your choice to make on if it’s important enough to debate over –but trying to invalidate a well researched and concise article because you don’t agree with the facts of it is absolute madness. Trying to convert your opinions and personal feelings into facts is a sign of an emotionally and intellectually lacking individual.


Also, in the spirit of lacking….add reading comprehension to your list

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