First of all, a ban on smoking might just lead to people deciding to turn on to the black market for tobacco, not solving the problem of passive smoking or any other effects. Same also goes for the possibility of higher taxation, people might just choose a relocation of funds due to higher prices of cigarettes.  Further on, if we do accept the premise, that smoking will maybe decrease, the evidence for passive smoking is very slim indeed, with very few controlled studies having been carried out. At most, those who live with heavy smokers for a long period of time may have a very slightly increased risk of cancer.  Also it is true that smoke-filled environments can be unpleasant for non-smokers, but there are reasonable and responsible ways around this - smoking rooms in offices and airports are an excellent example. Some bars and restaurants may choose to be non-smoking establishments, giving customers the choice to select their environment. Allowing people to make their own, adult decisions is surely always the best option.