This article on MSN is about how smoking weed doesn't hurt lung capacity, and from reading the article, if anything improves it (slightly)! Pretty interesting read actually if you are into such things. Its too bad the research on marijuana is so far behind and still dealing with inconsistencies due to the illegal nature of it, someday we will all be free to do as we please, in one way or another.
This is bad news for a lot of us though, instead of saying we smoke too much as an excuse for being out of breathe after a run through the trails, we now have to admit that we're just terribly out of shape (myself at least). But its also the perfect excuse to take more breaks to "improve your lung capacity." Now safety meetings not only keep you safe, but work out your lungs!
And just to add something random and interesting to this post...Juha Kankkunen is the man, and the raw audio of the different cars in this video is an added bonus.