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The Art of Clean Air

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

Household dust is not just “dust”, it’s 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 and fragments… just to name some.

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 multiply!

A portion of the dust comes from indoor sources, but a larger share comes from outside through the occupant’s shoes, hair, and clothing. The entry of mold spores from outside builds a seed reservoir of sorts, so mold accumulates in dust and remains 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 excessive mold in a home.

It 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, and itchy skin are a few of the symptoms that can be expected. Dust is particularly troublesome for asthmatics. So how do we control it?

1. Minimize sources

Our recommendations:

  • Selecting 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 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

We recommend: the best way to capture dust is with a high-quality, sealed vacuum. The right vacuum will minimize dust particles, especially micro particles, which are the tiniest particles that get deep into the lungs and affect health the most. See details below on vacuum cleaners.

Does frequent vacuuming wear out carpeting?  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.

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. It should be used to capture particles from floors, lampshades, electronics, window sills, baseboards, ceiling fan blades, etc.

3. Filter airborne dust

We have found that vacuums capture dust from surfaces but not from the ambient air. That is 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. We like 3M Filtrete filters. The furnace thermostat typically has a 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 percent when the furnace fan runs continuously instead of 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 your furnace motor’s life, but this is minimal.

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


Our experience is that standard 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 the construction of these vacuums often lets the microparticles escape the vacuum either through the seams or around the HEPA filter (called filter-bypass).

We 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 we conduct an air quality assessment, the last thing we do is test the vacuum. We use a particle counter to measure the number of particles in the air before turning on the vacuum, during 30 seconds of vacuuming, and after the vacuum has been shut off. While the vacuum operates, we measure the air coming out of the exhaust opening and ask the homeowner to write those numbers down. After the vacuum is turned off, we once again measure the particles in the ambient air and ask the homeowner to write those down. The purpose of this exercise is to make sure our 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, European S-Class filtration, when shopping for a vacuum. Canister vacuums are preferable as they are better sealed and they make it easier to vacuum objects or furniture surfaces.

Air Cleaners – Air Purifiers

We have found that 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, we find that it’s unpredictable how many particles are emitted by these machines. In a few instances, the devices 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.

A high-performance air cleaner (such as the FOUST or Austin Air units) will dramatically reduce the amount of dust and particles in the air before they settle and become surface dust. For a new house/condo, we recommend the Foust 400 Series (made in Wisconsin) or Austin Air Allergy machine (Made in New York State) to address formaldehyde and VOC emissions from new building materials, in addition to the airborne dust. These machines are effective, and a good investment, they are also made in the USA. Use the Austin Air Healthmate for standard air purification or Healthmate + for new or newly remodeled homes. For samllet rooms like home offices or children bedrooms, the Foust 160DT is ideal.

Maid/Cleaning Services

What if you 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 and cat dander from their previous client 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 pass. A backpack vacuum can recontaminate your home each week by distributing millions of fine particulates collected elsewhere on other jobs.

We had a particular instance of a retired couple with an immaculate home who wanted to have the air quality checked because they constantly had the sniffles. The cause was traced to the cleaning lady’s vacuum, used in dozens of locations throughout the week and leaking millions of fine particulates throughout the couple’s home each week. A dust analysis recovered high levels of cat and 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.