That's interesting. I've never seen "PAH" used for "disgusting" or "annoyed". In this area "PAH" is for positive accomplishment. Such as, someone trying to fix something over, and over again, and then "PAH", finally, success!
As a hearing person, if I'm frustrated or discouraged I might say "pooh" but I've never said "pah". If something's disgusting, I might say, "ewww" or "yuck" but not "pah". If something's annoying, I might say, "pfft" but not "pah". If an older British person hears something that he doesn't believe or accept, he might say, "bah!", as in "bah, humbug!" But not "pah". So, I don't think the "pah" sound has anything to do with sounds that hearing people make.
The closest I can imagine is, when someone is finally successful, they quickly breathe out a sigh of relief, and that might sound like a "pah".