The makeup of e-cigarette vapor is different than the what's in the liquid. When vaping, the e-cigarette coil heats up to 300°C and breaks compounds in the liquid (such as propylene glycol) into new compounds such as propylene oxide, acetaldehyde, and formaldehyde. Researchers found that aerosols generated by e-cigarettes contain up to 31 compounds, some of which are known carcinogens.

http://pubs.acs.org/doi/abs/10.1021/acs.est.6b01741

Wow, didn't know that. So, when the article says that "There are potentially hundreds of chemicals in e-cigarettes..." they are actually referring to compounds that are being generated after vaping?

I believe so, but he could also be referring to how there are hundreds of different flavors (each containing different compounds), and each compound interacts differently when heated by coils.

Thats the huge asterisk.

A successful vaporization requires temperatures of 150-200°C with a max of 250 for self-experimenting enthusiasts.

So when these studies include the chemicals caused by pyrolysis, they're not studying realistic e-cigarette use.

A good analogy would be studying the consumption of improperly distilled alcohol that included methanol- EXCEPT you wouldn't be able to taste the methanol in bad liquor, and you'd absolutely be able to taste burnt e-liquid.

I'd still have to imagine that the acetaldehyde and formaldehyde intake is a small fraction of what the average persona already ingests in the form of alcohol.

Which of course doesn't mean it is good for us but I think establishes that the danger from that is probably less scary than that sounds

My understanding is that this is a bit of a false alarm, because most devices target 150C, which is just enough to vaporize the PG, but not oxidize it, not 300C where things get ugly. So, with reasonable safety measures in place, this shouldn't be an issue.

The study I citied measured compounds produced by on-the-market e-cigarettes, specifically the EGO CE4 and Kanger Aerotank Mini.

While I'm not sure what temperature these devices target, what I know is that the researchers found that longer into a usage session the coils became hotter and produced larger quantities carcinogens.

My understanding though is that while e-cigarettes do produce carcinogens, they produce less quantities than regular cigarettes do.

Reading a lot of these studies, I get the feel that the researchers aren't really users of the devices, nor have they really consulted any real users of the devices. It's akin to someone who had never seen how a car works being surprised that they are capable of going over 100 MPH. Sure, they can, but usually people don't drive them around that fast. The same goes for e-cigarettes. Sure, if you max out the voltage, keep the coil red hot and dry out the wick you're going to get some bad stuff, but no real user would inhale much of this (at least not more than once) because it would taste terrible.

> most

I guess you had the link to the survey ready and just forgot to paste it. Would you find that again, please?

I also think it's significant that the liquid is vaporized. Certainly it's quite different to smoke tobacco than to eat it.

Vaporization is a physical state change, whereas combustion (and digestion) is a chemical change.

As tristanj pointed out elsewhere in the thread, studies have shown that chemical changes are happening. See the study tristanj linked, http://pubs.acs.org/doi/abs/10.1021/acs.est.6b01741

It's "potentially" because a study in the lab cannot demonstrate health outcomes. (Which, of course, requires people to be involved.) It's also wise to attach it to single studies: we don't tend to change views based on single studies, but on large amounts of studies that corroborate each other.

So, yes, I agree: this warrants much further study. I have not come to any conclusions, but I have updated my priros. But, independent of that, I felt some comments in this thread were misrepresenting what the research did.

The flavors must make some sort of difference. I have an e-cig. Not a huge user, but I notice that the resistors clog up a lot faster with the darker juices and last a lot longer with the clear ones. I am mildly concerned about the effects that they might have on health - because when I got it I had read stuff similar to your "two to three chemicals" line also saying that its essentially the same as an asthma inhaler, when the reality is somewhat different.