i was in a McDonalds the other day and a guy in line was smoking... you really can't avoid it... i, personally, can't go through a day without walking at least at one point next to someone who's smoking. for one, i can't walk into the college without passing through a cloud of smoke from all the people outside smoking.
now remember, i'm not saying that it's possible for people to avoid car fumes, because there's no way anyone can do that, no matter how cautious they are. and also remember i agreed with you that pollution's another problem, but i don't see it going away ever, because cars benefit people, smoking definately doesn't :-/