A Hotter Vape Emits Higher Levels of Carcinogens, Study Shows

Any serious vaper can tell you the many merits of their custom vape, from how it feels in their hand to how much power it's got. But those more elaborate rigs may also keep vapers from inhaling higher levels of harmful carcinogens, according to a new study.

First, a quick vape anatomy lesson. All vapes, even the most basic gas station cig-a-likes, are made of three basic components: a battery, an atomizer (that's a heating element), and a tank, which holds the liquid to be vaporized. On top of the atomizer is a small coil that gets heated up. As the e-liquid passes through the coil, it gets so hot that it turns into vapor.

Some more advanced devices have two coils, which allow vapers to heat up more e-liquid in one puff, leading to a more flavorful, dense vaping experience. But there may be an added benefit to the extra coil: lower levels of toxins. A study published Wednesday in Environmental Science and Technology detected 31 harmful chemicals emitted from vape devices, but found that a double-coil vape produced much lower emissions than a single-coil device, even when they tried different e-liquids.

"Not all devices are the same," Hugo Destaillats, a co-author on the study and a staff scientist at the Lawrence Berkeley National Laboratory, told me over the phone. "With two coils, the same voltage gets distributed evenly between the coils. Therefore, the amount of heating of each of them is lower."

Destaillats explained that the emissions he and his colleagues detected—which included formaldehyde and carcinogens like acrolein—are created through the decomposition of chemicals like propylene glycol, in the e-liquids. The higher a temperature you use to vaporize the liquid, the more decomposition you achieve. The study backs this up: as the devices heated to higher temperatures and voltages, higher levels of harmful emissions were produced.

Concerns have been raised in the past about the possibly toxic emissions that e-cigarettes produce, from formaldehyde to diacetyl—a chemical linked to a severe lung disease. And this study found two new toxins never before detected, propylene oxide and glycidol, which are both probable carcinogens.

Meanwhile, vaping advocates and researchers argue that the way users vape differs drastically from lab tests. To get the ultra-high emissions of nasty chemicals, you need to crank vapes up to a temperature so high, it cooks the e-liquid before it can vaporize, causing a nasty taste and sensation known as "dry puff" that stops users from continuing—so they may not be breathing in such high levels of toxins. Studies have backed this up, and Destaillats told me since these tests were done mechanically (and didn't have real people inhaling), he can't say for sure if vapers would use devices at the highest levels. But he noted that these toxins were detected even at the lowest levels.

Given the voltage and resistance of the devices used, it may have been above the dry puff threshold, according to Michael Siegel, a researcher at Boston University who studies e-cigarettes. But he told me the report is still important because it shows a link between temperature and the appearance of these toxins. And that connection could help inform better products and regulations.

"The bottom line is that if these products are heated to a high enough temperature, you're going to get those contaminants in there," Siegel said. "To me, the importance of the study is that we have the ability, technologically, to prevent that from happening. We can control temperatures."