Does sperm die when it comes in contact with air?!

Yes, but it needs to dry out as well.

Ejaculated sperm is protected somewhat by the fact that it is mixed with a lot of seminal fluid. The fluid keeps it moist longer and helps protect it from the (acidic) lining of the vagina.

Just letting ejaculate touch the air doesn't mean that the sperm have died right away. However, if a patch of ejaculate has dried out on something, it's pretty much guaranteed to be dead.

NO, no reason it would. Otherwise, how could guys provide a semen sample for testing or for invitro fertilization. They ejaculate into a specimen cup, and it is exposed to air for as much as an hour.

I suspect this recent myth was spread from hearing about the AIDS virus--- it does in fact die on contact with the air. But sperm cells are very hardy and can live for 48 hours or more when kept warm and moist. By the way, the vagina is exposed to the air, so any semen deposited there obviously isn't affected by air since we have nearly 7 billion people.

Many animals like frogs and fish deposit their sperm right on the eggs, again fully exposed to air or water.