Is Secondhand Vaping Harmful To Your Health?
Illustration by Jason Schneider

A small but disturbing study published last summer found that vaping indoors–even in a well-ventilated room–releases ultrafine particles and potentially carcinogenic hydrocarbons into the air. “Our data confirm that e-cigarettes are not emission-free,” the authors wrote. Still, studies of exhaled vapor find that such emissions turn up at concentrations so low they may not pose much of a health risk to bystanders (or vapers).

The Food and Drug Administration, which may be called upon to regulate e-cigarettes, remains cagey: “More data is needed to determine the constituents in e-cigarette aerosols and the potential risks of secondhand exposure.” But Igor Burstyn, an occupational health expert at Drexel University, argues they’re being overcautious. “It’s propaganda mixed with willful ignorance,” he says. “There are thousands of measurements from devices on the market.” His 2014 e-cigarette data review concluded that contaminants “pose no apparent concern” to bystanders.

This we can say for certain: You’re better off breathing in vapor than secondhand smoke. Tobacco smoke contains thousands of chemicals, 60 of them known carcinogens, says toxicologist Maciej Goniewicz. “In vapor, we find just a few of these, at much lower levels.”

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This article was originally published in the May 2015 issue of Popular Science.