Does the HIV virus die in open air?

I got cut by a weird guy with a knife two days ago. I'm at the hospital now waiting for a checkup but I'm wondering, if the knife was dirty (though probobably no blood on it) can I get HIV? Or is the risk REALLY small? It was a small knife and the one cut is miniscule- 1cm at best and not deep. The other is 1-2 inches but not deep at all. More like a scratch.