Mold and mildew are generated in the home and release spores into the air. Pollen is generated outside the home. Dust mites and animal dander are problematic when they become airborne during vacuuming, making of beds or whenever textiles are disturbed. Dust mites are the single most frequent trigger for asthma attacks. Molds thrive in areas of high humidity on organic materials such as paper, textiles, grease, dirt and soap scum.
Mold spores float throughout the house, forming new colonies where they land.
Dust mites thrive on dead human skin cells and in textiles, such as bedding, carpeting and upholstery. Infectious diseases caused by bacteria and viruses generally are passed from person to person through physical contact, but some circulate through indoor ventilation systems. To date, we have no practical way to test for biological contaminants, but you can watch for signs. Sometimes you can see and smell mold colonies growing on surfaces. Suspect mold growth wherever you see water stains, standing water or moist surfaces.