Many second-hand smoke studies are performed on spouses of smokers, over long periods of time (living w/ a smoker for decades, basically). Second-hand smoke in

Many second-hand smoke studies are performed on spouses of smokers, over long periods of time (living w/ a smoker for decades, basically). Second-hand smoke in say, a park (where smoking is frequently banned) is not a factor. It's a convenient lie to discourage smoking.