Do sperms die when it hits air?how much is the sucess rate of home insemination compared with normal intercourse?will it affect baby anyway?

No; air doesn't kill: Exposure to "air" does not kill sperm. And, at home "insemination" (placing semen/sperm into the vagina) is no better than intercourse: it will, also, not be as successful as actual artificial insemination since the treatment (better selection) of sperm, and placement further up (eg to cervical plug or into the uterine cavity) will be more accurate in approximating the sperm to the egg.