Anyone who doesn't smoke. Usually very arrogent and ignorant in their opinion. Generally, they make it a hobby to be as ignorant as possible to smokers. Tend to believe they're superior and better than smokers. Also, a majority have never smoked therefore can not understand it from a smokers point of view, but their arrogence blinds them of this. Their arrogence also blinds of the fact that the air in any decent sized city isn't much cleaner.
He doesn't smoke, therefore he's a non smoker.