There's also the aspect of "general bad manners" there. Those tend to be fairly consistently defined and treated when one deals with things of residue, smudge, smell or stain nature... If you leave a mark, you are likely to be universally hated.
Spitting has been out of the vogue since the early 20th century, and a person spitting indoors today is likely to get physically injured by his compatriots pretty quickly. There's the health aspect to it, with many diseases spreading or feared to be spreading in congested 20th century cities via expectoration. But there's also the general aesthetic aspect of it.
It might not be as common to kick the teeth out of a smoker's mouth as it would be to make an expectorator bleed today, but we're getting close. In the average bus around here, if there's a smoker who has the misfortune of not being wrestler-sized, and if there are average-sized men in there in addition to the person who expresses her displeasure on the subject of smoking, threats of physical violence towards the smoker will quickly ensue, and will be universally appalauded. (The situation where one of those average-sized men would be the first to express the displeasure is less likely to occur, it seems.)
That, more than any health concerns or statues, is likely to have an effect on public smoking. If it's considered unwelcome by a few, many will rally to show their support to those few in hopes of scoring... The natural result is that smoking will only continue in environs where threat of physical violence ain't a scoring factor as such - where one might have to follow through in order to gain anything. Basically, smoking is becoming the vice of the "criminal classes" for purely ego- and fashion-related reasons!
Timo Saloniemi