Importing Indoor Air Quality Problems

May 17, 2021 Bob Krell

By Jeff May — Healthy Indoors Magazine-USA Edition April 2021

Many indoor-air-quality problems are caused by building conditions, such as poor ventilation or moldy heating or cooling equipment. But some sources of indoor air quality (IAQ) problems are brought into buildings by occupants.

Below are some of those surprising, everyday possessions that can expose building occupants to contaminants, allergens, and irritants.

Books. Books that have been stored in an unconditioned space (not heated or cooled) such as a damp basement or garage can acquire mold growth on the spines, covers, or even inside the pages if the books have ever been damp. If any of your books smell musty, without opening the books you can carefully HEPA vacuum the covers and spines and then air the books outside in the sun. But any books that contain visible mold growth should probably be discarded. If the books are valuable, you can keep them in tightly lidded plastic boxes, and only open the box outside (wear a mask when doing so). In the end, though, it’s just not a great idea to have moldy books in your home or office, because every time you open such a book, you will be exposed to mold spores, which remain allergenic even when dead.

Mold growth on books and a bookshelfMay Indoor Air Investigations LLC

I always recommend that my clients use a HEPA vacuum, which has a “high efficiency particulate arrestance” filter, because conventional vacuums can emit potentially allergenic particulates in the exhaust stream.

Furniture: Many antiques at some point have been stored in a damp basement, garage, or other unconditioned space. I often find visible mold growth on such pieces, especially drop-leaf tables.

Mold on the bottom of a drop-leaf tableMay Indoor Air Investigations LLC

Exterior walls can be cooler than interior walls. Air and surfaces next to exterior walls can be cooler than air and surfaces in the middle of a heated room. As air cools, its relative humidity (RH) rises, and many species of mold can grow with the RH is over 80%. 

You can remove surface mold growth from solid surfaces, but upholstered pieces may have to be reupholstered or discarded.   

Cushioned furniture can also be infested with dust mites. One woman used to suffer allergy symptoms whenever she was at work. She was sure there was mold in the wall-to-wall carpeting or the building’s heating system. The culprit ended up being dust mites in her upholstery-covered office chair, which she had brought into the building from home. She replaced the chair with a leather-covered one and her symptoms abated. I always recommend that people with allergies, asthma, or other environmental sensitivities avoid sitting for long periods of time on fabric-covered furniture.

Furniture can contain pet-dander particles. If you or anyone in your household has pet allergies, turn down that couch that your aunt wants to give away, because her pet cat’s dander-particles could remain on and inside the upholstery forever. I have asthma and many allergies including pet and mold, and when I sit down in someone else’s home, I always try to sit on solid wood furniture!

Micrograph of dog-dander particle (oblong) and human skin scales (round), stained pink with acid fuchsinMay Indoor Air Investigations LLC

Feathers: Oft-used feather-filled items can acquire dust-mite infestations. In addition, fragments of feather fibers are irritating to inhale, and some feather-filled goods emit bird-bloom particles, exposure to which is a recognize cause of the serious respiratory illness called Duvet Lung: a type of hypersensitivity pneumonitis or HP. One of my client’s daughter gave him an expensive feather-filled quilt. Shortly thereafter, he began to experience respiratory symptoms that caused serious shortness of breath. He took the quilt off the bed and his breathing improved. Area rugs: Rugs can contain mold spores and mite droppings, particularly if they’ve been stored in a moldy space; been placed directly on concrete (for example in a basement or a room built on a slab <concrete> in contact with the earth); or have been in a cold space such as an enclosed porch or a room over a crawlspace. I worked with one family whose 3-year old son had asthma.

Read the full article in the April 2021 USA-Edition of Healthy Indoors Magazine at:

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