[Ditter]

Is 2nd hand smoke the smoke that smokers exhale? I am guessing that is has been filtered through the smokers lungs but what about the smoke that burns off the end of the cigarette? That would be just regular smoke like the smoker inhales, nothing 2nd hand about that.

[stephenjohnbanker]

Harvard study was over 5 years, and used a large room, with no ventilation.