Electronic cigarettes are often marketed as a healthier alternative to regular cigarettes, but that doesn’t mean they’re good for you. In fact, The Verge reports, researchers at the Lawrence Berkeley National Laboratory recently identified 31 harmful chemicals in e-cigarette vapor, including two probable carcinogens, or cancer-causing substances.

In a study published in Environmental Science & Technology, researchers explained that the thermal decomposition of propylene glycol and glycerin, two of the main solvents found in e-cigarette liquids, produces a vast range of toxic chemicals. These include propylene oxide and glycol, which researchers believe are carcinogenic.

Researchers also found that levels of chemical emissions were dependent on heat, the type of e-cigarette used, and the age of the device. In general, as e-cigarettes grow warmer, they release more chemicals. That means the first few puffs of an e-cigarette as the device heats up generally contain fewer chemicals than subsequent puffs. Additionally, researchers discovered that e-cigarettes with just one heating coil emitted more chemicals than those with two, and that as devices aged, buildup of residues on the coils also caused an increase in chemical emissions.

While the levels of chemicals emitted in e-cigarette vapor were lower than those emitted by cigarettes, researchers say that doesn’t make them safe. For instance, while regular cigarettes emit between 400 and 650 micrograms per cigarette of acrolein (an eye and lung irritant), e-cigarettes emit closer to 90 or 100 micrograms in the 20 puffs (approximately the equivalent of a traditional cigarette). While that’s substantially less acrolein per puff, it’s still enough to alarm scientists. 

“Advocates of e-cigarettes say emissions are much lower than from conventional cigarettes, so you’re better off using e-cigarettes,” researcher Hugo Destaillats explained in a statement. “I would say, that may be true for certain users—for example, long-time smokers that cannot quit—but the problem is, it doesn’t mean that they’re healthy. Regular cigarettes are super unhealthy. E-cigarettes are just unhealthy.”

[h/t The Verge]

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