It's time to change the Air filter in the unit.
You probably have mold on the evaporator coil.
Normal air..... Smell like you
the air conditioner is a big dehumidifier. crawl space is getting wet. probably mold
there is a leak in the compressor...
It is probably mold growing inside the air conditioner, which blows out into the room. This is fairly common, especially if the humidity is relatively high in your area. If your carpets are damp, they too can harbor smelly mold.
There might be mold inside the air shaft or there is something smelly near it and it's scent is being blown
yes, you can smell it in the air. It smells like a smouldering burning smell.
there's actually a name for that and its called Dirty Sock Syndrom.. what causes it i believe is that the aircoditioner is not draining right and there is mold build up on the coils..
Compressed air used for SCUBA should smell like regular air. There may be a slight rubber smell from the regulator. When in doubt, it is safer to get your tank refilled than to dive on contaminated air.
Helium is like air. It doesn't have a smell. But it tastes awful!
dead mouse inside the furnace
Yes mold, like fungi, breeds with the release of spores into the air. Many mold spores are poisoness to humans and that is why you dont want it in your house. ;)