<p>@ucbalumnus - The study you cited was comparing the effects of second hand smoke -indoors- to the effects of car exhaust. That’s hardly a fair comparison given the subject of this thread. We’re not discussing the effects of being trapped inside and exposed to high amounts of second hand smoke. We’re referring to the effects of essentially walking past a few smokers outside and being exposed to it for a few moments. </p>
<p>This doesn’t really seem like a very realistic comparison. One is constantly exposed to car exhaust. Everywhere. You can hardly walk outside without being exposed to it. One is breathing in car exhaust before, during, and after walking past that group of people that are smoking. </p>