Did you know that there is such a thing as 3rd hand smoke? It happens when a person who smoked has already left a place. The fume stays for a while in the place where a person smoked and when another person arrives at that place, he/she experiences 3rd hand smoke. This especially happens when an ash tray is present. It may not be as harmful as 1st and 2nd hand smoking but it can still put someone's health at risk.