I am ambivalent about this but, on balance, come down on the side of the government having the constitutional right to protect non-offending, non-smokers from those who are indifferent to the discomfort their behavior causes others. This applies only to state governments of course. You would have no problem with a state law whidh prohibits peeing down your leg, or against a factory which emits noxious fumes or effluviants, or which prohibits noisemakers at operas.
This is not to say that a state government always has a duty to exercise its constitutional prerogatives to protect its citizens from behavior which is merely obnoxious or offensive. I believe that most of these anti smoking ordinances have been justified because they protect non smokers from the health hazards of second hand smoke. This brings most of them within the constitutionally permissable area of public welfare. I know a new study just out perports to debunk this notion, but a legislature or city council is not required to believe every new study.
Problems arise when the government seeks to regulate smoking outdoors where health hazzards to others are clearly remote as in such places as football stadiums or courtyards. How can this be constitutionally permissable? In Singapore it is illegal to chew gum on the street because you might litter the wrapper. Would this justification pass constitutional muster in America? I think not, but there is no guarantee if Hillary ever gets to appoint more Justices like Ginsberg. Could the Mallibu city council pass an ordinance prohibiting smoking anywhere (including in your own private home) because it wants to protect the smoker himself? It can regulate liquor if authorized by the state, why not smoking? At some point a social policy which can be justified because it allegedly advances some permissable police or general welfare goal becomes unconstitutional because it too remote or encroaches on some other value like the right to be left alone, or to speak freely, or to associate freely with (only)those whom you chose.
But I do think that among the electorate there is a growing and alarming tendency to ignore whether a matter is constitutionally permissable and to consider only whether it is viscerally desirable. At this point, everything becomes a public relations game.