Here in Florida in our last election there was a popular vote to ammend the state constitution to make smoking illegal in restaurants (similar to NY and CA). The ammendment passed with about 71% for the ammendment and 29% against. They (media) said that the ratio is almost the same as the nationwide average of smokers (just under 30%) and non-smokers (just over 70%).
I voted against the ammendment by the way. I'm a smoker, but I would have voted the same even if I wasn't. I have a hard time believing that the risk to non-smokers from smokers is as high as 'they' say... just my opinion. FYI - I started at around 13 years old (35 now). Stupid teen agers...
As to diving, I haven't found smoking to have much effect in general. I've found my air consumption to be about average with other male divers. But who knows... maybe if I didn't smoke it would be that much better, in fact I am sure it would, but I am not ready to quit. When I was getting certified back in '93 I was concerned about it. Not so much for safety reasons, but I figured the instructors or other students may look down on me for smoking. Well, I didn't hide it, but I didn't go around blowing smike in people's faces either. It looked like the only two smokers in the class were me and my buddy who I took the class with. The class had about 20 students with 5 instructors/DMs. On the first day of our check out dives I wanted a smoke between dives (at Dutch Springs in PA). I looked around for some other smokers and 3 of the 5 instructors turned out to be smokers. That really surprised me, but it was also a relief.
Smoking is certainly unhealthy and I would never recommend it, but its a personal choice and if divers or any adult want's to do it, that's their right.
-Joe