Why not put the same restrictions that hemp cultivation has, 1/4 mile from any 'business' where the general public can freely enter. During prohibition the 'problem' was solved by the formation of private clubs. Entrance is by membership that includes signing a waiver that covers smoking and all sorts of other 'rights'. You accept the consequences that might also include medical care for smoking related illnesses. Such a place would be expected to have higher than normal filtration systems (ie tables would have a surface that allowed for a vacuum to all ashtrays) All smoking material would be sold in-house via purchased credits and vending machines, add in whatever else can be offered and that is more humane than killing the 'addicts'. My bar is How the West was Lost. then have a cigar-store theme complete with fake cigar sales at the door. That is where the tokens are purchased via a 'membership card'. Anybody who has ever bought beer ater the bars have closed is familiar with these 'clubs/houses'. The legit way has lots of tax deductions BTW etc.
Give the smokers the seeds to grow their own, if that is too much trouble, they just became non-smokers. Butts are eliminated just by making all cigs the ones you roll yourself, the whole butt is recycled into the next cig, or it is so small it is not 'pollution'.