Flavor compounds in mainstream tobacco smoke are either naturally from the tobacco leaf or as additive ingredients.They do not significantly contribute to the total particulate matter (TPM) of tobacco smoke.However, the flavor additives are very important for the taste of the cigarette and cigarette smoke."Good taste" is also one of the reasons of smoking by teenagers and many adult smokers.The yields of flavor compounds in mainstream smoke are mostly from ng/cigarette to μg/cigarette.