Originally Posted by
DrIsotope
If you're a human, it doesn't matter how the air goes in, it still passes through your throat. But you might be an egret, and swallow fish during rides (while breathing.) I dunno.
Air entering through the nose is filters and moistened by the nasal cavity.
Ever ride in 30* weather, if you breath through your mouth you'll have a VERY sore throat. But if you breath through your nose, you'll be fine.
Or maybe you're a dolphin and have a "blow hole".