Healthy Indoors Magazine - USA Edition

24 | June 2020 Did You Know That? ©2020 Jeffrey C. May 1. People living in homes with central air con- ditioning, hot-air heat, and/or finished, car- peted basements are more likely to have allergy symptoms. I once compared data from inspections I did of 300 "control homes" to 600 "sick homes," where occupants were suffer- ing from allergy symptoms. I found that people with allergies or asthma were about twice as likely to be living in homes with central air conditioning. People living in homes with hot- air heat and carpeted, finished basements were also more likely to experience respiratory symptoms. Air conditioning can be problematic because the dust on the damp cooling coils acquires microbial growth. 2. Furniture kept in a damp basement can ac- quire mold growth. Aspergillus mold growth on a highchair May Indoor Air Investigations LLC This highchair has visible mold colonies. When their first child outgrew the highchair, her parents stored the chair in a damp basement. When they had their second child, they used the chair again without cleaning it, exposing their baby to mold growth. 3. Dust is the Devil! Most of the dust in homes consists of skin scales that people shed. Other dust particles can include food bits, lint, mold spores, and pollen grains. Biodegradable dust can serve as food for hordes of microarthropods. Carpet-beetle and wool-moth larvae feed on wool fibers, booklice feed on pol- len grains, and mites feed on skin scales, mold spores, and even other mites. Spiders then suck the microarthropods dry. The final result of the invisible struggle is microscopic and macroscopic bug poop, all of which is highly allergenic. Droppings from a carpet beetle larva full of bits of chewed off hair (all stained pink).A cellulose fiber is at the far right. May Indoor Air Investigations LLC A carpet beetle larval hair (lower left) and a human hair (upper right) with bites from a carpet beetle larva. May Indoor Air Investigations LLC

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