oh AND ....
How many times have you smelt that gungy off smell from your own car air conditioner?
Call me fussy, I try to shut it off before [nominal time in minutes = 2 or 3] coming to a stop, with the fan on fresh/high to evaporate the condensation out. Works for me, no gungey smell, no organisms?
Don't get that smell in my 1993 GQ a/c on most of the time. Depending on the age of your vehicle it may have a pollen filter has it been changed, check the drain hose is not partially blocked blocked letting water escape properly or buid up or lay somewhere.