Cigarette smoke: not only does it smell pretty awful, it’s poisonous and carcinogenic. Harmful not only to those who use it but also anyone in the vicinity of users.
Car exhaust fumes: ditto.
The government has banned smoking in public places. This prevents harm to those who choose not to smoke. We stigmatise smoking and offer users ample help and encouragement to wean them off it. The ban has been a triumph in England: “28% have stopped smoking and 43% have tried. Tobacco sales have fallen at twice the previous annual rate and there has been a 3% drop in hospital admissions for heart attack. … That shows how a determined government can make the weather, if it dares.”
Car driving: not ditto.
Another simple comparison:
If you sit two people in a garage and one is smoking, the worst that will happen to the non-smoker [in the short-term] is maybe some eye irritation from the cigarette smoke.
If you sit two people in a garage with a car running and the exhaust blowing into the garage your gonna have two dead bodies before long.
It would seem that car exhaust is much more dangerous then second-hand cigarette smoke.
from this discussion page