What is secondhand vapor?

Secondhand vapor (which is technically an aerosol) is the vapor exhaled into the atmosphere by an e-cig user. Like secondhand smoke, it lingers in the air long enough that anyone in the same room (assuming the room is small enough) is likely to inhale some of the exhaled aerosol. As the name indicates, the bystanders are not inhaling secondhand (or passive) smoke—because secondhand e-cigarette vapor simply isn’t smoke.

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

E-cigs heat e-liquid with a small metal coil housed in an atomizer, and the heat turns the e-juice into the vapor you see. E-cigarette vapor doesn’t have any carbon monoxide or tar, and the particles in the aerosol are liquid rather than solid. Dangerous chemicals and metals are found in vapor, but only in tiny quantities. The levels of toxicants are minute compared to those found in smoke, which means the dangers of secondhand vaping are less significant.