Before you say " no one cares about them anyway, those filthy cancer-spewing polluters," think about this: you are going to a bar to drink a poisonous mind-altering substance, and, if you are lucky, to have the shot at contracting a sexually transmitted disease, but you still want to be free from second-hand smoke? Protect those lungs from cancer, never mind the liver and genitals!
As for the "overall results positive" section of the linked article, I don't buy it because it is speculative and vague. Furthermore, even if it turns out to be a good thing for businesses (doubtful), there is no need to use the power of government to help out the bars. I thought lefties were against corporate welfare.