I have a major problem with people smoking on the streets. The first main reason is obvious, but the second reason is some jerk was being careless with his "flame" and almost burned me!
I did see a tv program where someone invented the "smoke wall"! It was like a ventillation system that blew fresh air directly in a downward direction to isolate the smoke from lingering outside it's perimiter, while it sucked the smoky air up into the ventillation system. It looked pretty effective, but I have no idea what kind of price is involved.
There was also a "test" done in one district in the Osaka city limits. In a one-block area, they banned smoking on the streets and would fine those who didn't follow the law with 1,000 yen (about 10 bucks). I don't know if it was effective, and how much further they're going to expand that area, but it looked like a great idea...keeps all those cigarette butts off the ground, too!