Breathing mold spores is not good
Either water is not draining correctly, or there is leaf matter collected in the coils or i hate to say it, rodents have stopped in and laid the ground work for a home (bet you thought the first guy was kidding). Most likely the problum is water draining improperly. There is probably stagnant water sitting in the base of the unit. Most of te time this water evaporates but if it doesnt... Stink time!!! Best way to keep it frebeez fresh is to once a year clean out the base of unit being sure to get the dirt and lint out. Change you filter as recomended by the manufacturer and the problum should go away. Hopefully this helps