I sometimes start to cough and gag when contractors arrive wearing contaminated work clothing. If you sit on an infested furniture cushion, some mites may cling to your clothing. The next place you sit, a few may drop off to start a new colony. In homes with very infested carpets or bedding, the activity of children jumping and playing is enough to make the mites airborne. By looking at dust samples with a microscope, I have found that mites are very fond of grazing in mold on bathroom ceilings and basement walls and even on damp refrigerators cases.
Dust mites are rather fragile creatures and they can easily be broken apart .
Air samples often contain mite legs and other parts. Although these are allergenic, the most potent allergens associated with mites are in their fecal pellets. Dust by definition is a collection of particles that settle out of the air. It includes mold spores, pollen, clothing fibers, decayed plant material, combustion and soil particles, etc. If you don't believe this, just rub your arm or pet an animal or shake some clothing in a beam of sunlight in a room.