Anyone who smokes (smoked) knows firsthand the effects. There is no need for a scientist to inform you, but then maybe you need some great swampland cheap, in which case, do I have a deal for you. And one could find a so called 'scientist' who believes just about anything and will prove it with statistics, colored slides, and diagrams galore. I quit long ago, but I still remember getting up and clearing my throat before the first smoke. And if it can do it to the individual surely the person nearby will be affected. Plus isn't it great to come home from a restaurant and not smell like an ashtray? And look at the faces of long time smokers, me I still look like a baby - I wish!