Wait! I Know Second-hand Smoke. But What's Third-hand Smoke?

We all know that cigarettes produce second-hand smoke that is harmful to human health.  So have you ever heard of third-hand smoke?  Could e-cigarettes do the same?  

Q: What's Third-hand smoke?

A: Third-hand smoke is generally considered to be residual nicotine and other chemicals left on a variety of indoor surfaces by tobacco smoke. This residue is thought to react with common indoor pollutants to create a toxic mix. This toxic mix of third-hand smoke contains cancer-causing substances, posing a potential health hazard to nonsmokers who are exposed to it, especially children.

Q: Is there a problem with second-hand and third-hand smoke from e-cigarettes?  

A: Cigarettes produce smoke (solid burning turns to gas), while e-cigarettes produce steam (liquid turns to gas). So the smoke tends to remain in the air and on skin, clothing and furniture, whereas vaping from e-cigarettes tends to dissipate in the air, leaving no residue.

In terms of working principle, e-cigarettes are only vaping liquid, and do not produce second-hand smoke, let alone residue in clothing and other places;  In terms of flavor, e-cigarette liquids are generally fruit, mint, cream and other flavors without creating an unpleasant odor.  

As a result, e-cigarettes can be considered largely harmless to the people around them.