The Science of Housekeeping and how it affects your air quality

by Martine Davis, BBEC

When I investigate homes, a good portion of air quality problems stem from a particle or dust control issue. Understanding how to control particles or what we call “dust” can greatly improve air quality and how you feel in your home.

Household dust is a mix of skin cells, outdoor soil fragments, pet dander, cellulose fibers from clothing, paper, carpets and rugs, insect and rodent fecal pellets, pollen, soot from candles and traffic exhaust, pesticide dust, insect parts, food crumbs, mold spores & fragments, to name some. A portion of the dust comes from indoor sources but a larger share is brought in from outside via the occupants shoes, hair and clothing. Yes, you can pick up cat dander and mold spores on your clothes and hair and bring them into your home!

To compound the issue, dust mites live off skin cells which are plentiful in household dust so the more dust, the more skin cells, the more dust mites … Dust mites are not just found in bedding, they can be in upholstered furniture, draperies, rugs and carpeting. Add some humid weather and they really multiply!

Worse yet, the entry of mold spores from outside builds a seed reservoir of sorts, so mold accumulates in dust, remaining dormant until the humidity and temperature are optimal then germination begins. In other words, dust promotes mold growth and mold problems. After all, dust is mold food just like drywall paper. Besides water intrusion, dust overload can be a cause of too much mold in a home.

Even if the dust contains nothing out of the ordinary, even if it’s just plain household dust, too much of it can still be an irritant and cause symptoms in sensitive individuals, especially asthmatics. The amount of dust floating in the air also affects your perception of air quality, especially if there are tiny fiberglass fragments that shed from insulation through can lights, ceiling light fixtures or ceiling fans. Nasal and eye irritation, sneezing, itchy skins are a few of the symptoms that can be expected. Controlling dust is a huge component of air quality. So how do we control it?

1. Minimize sources
This would include things like favoring leather furniture over cloth upholstery, hard surfaced flooring over carpeting, metal or wood window treatments over draperies. Reducing clutter is essential to keeping dust down. Check for leaky clothes dryer vents. Implement a no-shoe-policy to reduce bringing outdoor pollutants. Showering in the evening will reduce dust particles deposited from hair onto pillows, linens and into the bedroom. For people who work outdoors and/or in polluted environments i.e. farmers, carpet cleaners, people who work in basements often like plumbers, heating & cooling contractors, pest control contractors, removing work clothes immediately upon returning home is essential to prevent “shedding” mold fragments, mouse and cat allergens, pesticides, etc. from clothing and hair.

2. Capture surface dust
The best way to capture dust is with a high-quality, sealed, vacuum. If the vacuum is the right one, nothing will beat it to minimize dust particles, especially micro particles which are the tiniest particulates that get deep into the lungs and affect health the most. See details below on vacuum cleaners.

Does frequent vacuuming wear out carpeting?
Actually, the opposite is true. What wears out carpeting is the friction from dirt and grime being pushed against the fibers creating abrasion so frequent vacuuming reduces this process and extends the life of the carpeting. The same goes for rugs.

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Isn’t sweeping and mopping just as effective?
Sweeping pushes the dust around and in the process aerosolizes the finest particles. These same particles may float in your breathing zone for a while then eventually deposit on furniture again. So nothing is gained with this process. When it comes to dust and dirt, a high-quality vacuum is the most effective, and it should be used to capture particles not only from floors, but lamp shades, electronics, window sills, baseboards, ceiling fan blades, etc.

3. Filter airborne dust
Vacuums capture dust from surfaces but not from the ambient air, that’s where filtration comes in. If your house is heated/cooled with forced air (furnace, central air), a good quality, pleated filter on the furnace can serve as a mini whole-house air purifier. I like 3M Filtrete filters. The furnace thermostat typically has an FAN ON and FAN AUTO position. Leaving this switch to the FAN ON position will cause the furnace fan to circulate air through the system all the time rather than when the furnace heats or cools the space. It has been shown that particulate counts can drop by up to 80% when the furnace fan runs continuously as opposed to the furnace fan operating intermittently during heating or cooling cycles. Of course this trick is not an option if you have an old, loud furnace or if the furnace is located near mold or other contaminants. This method adds a few dollars to your electric bill and it can also slightly shorten the life of your furnace motor but this is minimal.

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If you don’t have a forced air system, i.e. baseboard heaters, wall air conditioners, in-floor heating, then a good quality air purifier or air cleaner is essential to minimize airborne dust. See below for more on air purifiers or air cleaners.

Vacuuming

Common house-cleaning practices do less to remove dust than they do to aerosolize and relocate it. Take the vacuum cleaner for example. Most vacuums sold today tout a HEPA Filter which should be an improvement over the older vacuums right? Well in theory yes, but but the construction of these vacuums most often let the micro particles escape the vacuum either through the seams or around the HEPA filter (called filter-bypass).

I have personally tested hundreds of vacuum models over the last decade and found that most of them leak an enormous number of fine particles. When I conduct an air quality assessment, the last thing I do is test the vacuum. I use a particle counter to measure the number of particles in the air prior to turning on the vacuum, during 30 seconds of vacuuming, and after the vacuum has been shut off. While the vacuum operates I measure the air coming out of the exhaust opening and ask the homeowner to write those numbers down. Then after the vacuum is turned off, I once again measure the particles in the ambient air and ask the homeowner to write those down. The purpose of this exercise is simply to make sure my point gets across: Your vacuum pollutes the air every time you use it unless you have a well-designed, well-made, low emission one like the Nilfisk, Miele or Sebo vacuums. Look for words like “sealed” or “low emissions” or even better the European S-Class filtration when shopping for a vacuum. Canister vacuums are preferable as they are better sealed.

Air Cleaners – Air Purifiers

Not all air purifiers reduce household dust. Some air cleaners, like ionizers, don’t capture dust at all. The negative ions cause dust particles to stick to walls, electronic appliances and other nearby surfaces. Some air purifiers have UV lights that emit polluting ozone. Some HEPA air purifiers have such poor construction that they, like the leaky vacuums, put out almost as much dust as they take in. In testing dozens of air purifiers, I find that it’s unpredictable how many particles are emitted by these machines. In a few instances, the machines were increasing the number of particles in the ambient air! The majority of brands do a great job with larger particles but miss the fine particulates which are the most troublesome for our lungs.

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A high-performance air cleaner (such as the #1 rated IQAir HealthPro Plus) will dramatically reduce the amount of dust and particles in the air before it settles and becomes surface dust. For a new house/condo, I recommend the IQAir MultiGas GC to address formaldehyde and VOC emissions from new building materials, in addition to the airborne dust. I also highly recommend the Austin Air line. They are very effective, smaller in size and the value for the money is the best. Use the Austin Air Healthmate for standard air purification or Healthmate + for new or newly remodeled homes. I also love the Junior line, these are smaller in size and perfect for bedrooms or small offices with very little noise.

Maid/Cleaning Services

Don’t have the time or patience to do the cleaning? Hire it out, right? Well, only if the staff uses YOUR vacuum cleaner unless you want some mouse droppings & cat dander from the Jones next door or the mold spores and pesticide dust from that warehouse downtown. Most cleaning services use cheap, leaky vacuums, capable of polluting your entire home in one single pass. A backpack vacuum can re-contaminate your home each week by distributing millions of fine particulates collected elsewhere on other jobs. I recall a retired couple with an immaculate home who wanted their home air quality checked because they constantly had the sniffles when they were home. The cause was traced to the cleaning lady’s vacuum, which was used in dozens of locations throughout the week and leaked millions of fine particulates throughout the couples’ home each week. A dust analysis recovered high levels of cat & dog allergens (the couple had no pets) not to mention mouse, cockroach, molds and high quantities of dust mites. Cleaning services are great in keeping a home clean and healthy, but only if your own equipment and your own green cleaning products will be used.

© Copyright 2017 – Martine Davis