I have one friend who got second-hand high from being in a room with people who were smoking. Her default state is nearly stoned and she's very, very sensitive to weed. She was also in the room for quite some time. For most people, unless it's a tiny closet filled with smoke, I doubt it'd have any effect.

not unless your trapped in a hotboxed car

probably not. your eyes will get red, and you will fail the next random piss test.

Whether or not marijuana smoke breathed second-hand causes a buzz or not, it certainly can leave traces of it in your body. Specifically, the chemical known as tetrahydrocannabinol, or more commonly, THC, can be found in the urine for a day or so after inhaling the smoke second-hand. Often this second-hand inhaling is not sufficient to fail a drug test, and many drug tests have deliberately high standards in order to lower the possibility of false positive test results from second-hand smoke ingestion. So it may not be enough to get you "high", but it certainly could lead to you going one step further and starting to partake in the drugs yourself. Hanging out in a room full of smokers when claiming to be abstinent of that very act is like letting the fox guard the hen house, and even worse, you are the hen that let that fox be the guard. You will want to avoid these situations while you get your life back on track, and to tell you the truth, even when you feel you have a strong resolve against smoking, you will need to avoid being around smokers throughout your life, as you probably have a weakness towards this particular habit from your past use. It's best to forget that it's even available once you are over the hump. For more insights, you can read the upcoming blog that I contribute to: http://efyt.com/quit_marijuana I wish you the best in all your endeavors.