Yes, but you can't breathe in alcohol.
If you don't want to breathe it, it'll probably be hard to because everyone will be smoking a joint.
The second-hand smoke effects of marijuana are not that bad. In comparison to cigarette smoke marijuana is harmless. Still the drug is psychoactive, which means it impairs a few brain functions while you're under the effects. Moral of the story, don't smoke pot while driving, you crazies.
Legalization is mostly a moral issue right now since pot doesn't have many detrimental effects if any at all. The cigarette is far more dangerous then pot in every respect and it's perfectly legal. There are also some other psychoactive drugs that have been legalized but simply for their health benefits, which is also the main reason for trying to push pot into legalization.
Personally I am for the legalization for numerous reasons that go well beyond the simple-minded "Lol more car accidents" stuff, the health benefits being the major reason of course.