1) Gaseous particulate that emerges from one's butthole, known colloquially as a fart.
2) The condition of the atmosphere after a donkey has spent time in it.
1) Some asshole's assair has really fouled the air.
2) I wish you'd keep your donkey outside; the whole room reeks of ass air.
Similar to the phrase "Blowing smoke up my ass" but telling a person a lie to avoid telling the truth. This is especially done when caught in the wrong or other compromising positions.
"Jim caught his wife with another man at McDonalds; they were holding hands and everything!"
"Really, what happened?"
"Well she started trying to say the guy was just a friend"
"Seriously?"
"yep, I heard Jim kicked her ass to the curb, now she's staying with her 'friend' at his place."
"Man doesn't that beat all."
"Yes sir. I don't know how he's handling it so well... I would kill my wife if she was cheating on me, and then tried Blowing Air Up My Ass."
A sunburn or suntan focused on the left arm. It is caused by the left side of the body being the only half that gets exposed to sunlight while driving. Presumably, it would be located on the right side of the body in countries where they drive on the left side of the road.