It's not harmful at all.
No it's not harmful in healthy males.
No
No it cannot, unless you are allergic to your partner's sperm. But, even then, it will not be harmful, just causing an allergic response of hives.
No it is not.
Air bubbles in sperm aren't harmful at all. The presence of air bubbles in sperm may indicate that the sperm mixed with air on the way out of the penis, or mixed with air shortly after.
definitely if you are a woman
Not unless he has a STD.
No, not at all harmful and perfectly natural and healthy.
It should not be physicially harmful.
Assuming your partner is disease free, then no.
No, not unless your partner has a disease