Electronic Nicotine Delivery System.
The World Health Organization defines ENDSs as devices that do not burn or use tobacco leaves but instead vaporise a solution the user then inhales. Electronic cigarettes are the most common prototype of ENDSs.
The main constituents of the solution, in addition to nicotine when nicotine is present, are propylene glycol, with or without glycerol and flavouring agents. ENDS solutions and emissions contain other chemicals, some of them considered to be toxicants.