When somebody walks into a room after a smoke break, even a cigarette break, everyone within 15 feet knows it, especially non-smokers who are always repusled and disgusted. Sorry, that's just how it is. Chewing 20 packs of gum won't change this much because the smoke is all over you, your cloths, your hair. The only solution I know is to shower up, brush teeth, mouth wash and clean cloths.