Doesn't breathing car exhaust also lead to health problems? How come I can't walk down the street, or ride my bike, without breathing car exhaust? I swore as a child that when I grew up I would move to where there isn't so much car exhaust, but I guess there really isn't anywhere to go to escape it.. Yet they ignore that, and stress second hand cigarette smoke as dangerous?. Breathing car exhaust must be as bad, or worse, than second hand tobacco smoke. How about banning cars from the city center? They do it in Singapore. But maybe that would alienate voters, most of who could never live without their cars...