From pollen spores to dust mites, an invisible army of allergens is lurking in your plush wall-to-wall. While a simple footfall can send these potent allergens airborne, the updraft they crave most may be the one you least expect: your vacuum cleaner exhaust.

Logic says that vacuuming your carpet should remove airborne allergens from your home. Problem is, many allergy-provoking particles are as invisible to your vacuum cleaner as they are to you. Why? Because microscopic allergens escape the average vacuum cleaner through the exhaust and blow back into the air you breathe.

Vacuuming is enough of a challenge that the American Academy of Allergy, Asthma & Immunology recommends eliminating wall-to-wall carpeting from your home. What’s a carpet-lover to do when removal is not an option?

Central Vacuuming: Your Best Choice

You’re fortunate if you live in a home with a central vacuum, which sucks dust and particles into ductwork inside the walls, then exhausts them outside through a valve in an exterior wall. When Danish researchers at the National University Hospital in Copenhagen tested central vacuum cleaning systems, the study found that these release far fewer allergens into the air than standard canister vacuum cleaners. Unfortunately, retrofitting an existing home with central vacuuming can be costly. That’s why a high efficiency particulate air (HEPA) vacuum is the next best thing.

HEPA vacuums: allergist recommended, clinically proven

Because they’ve been proven effective in trapping microscopic particles, HEPA vacuum cleaners are now recommended by the American Academy of Allergy, Asthma & Immunology (the foremost authority on asthma and allergy treatment).

One 1999 study at the University of Virginia Asthma and Allergic Diseases Center, Charlottesville, Virginia, concluded that HEPA filter vacuums did indeed reduce allergen leakage. However, researchers also noted that more studies are needed. While the Charlottesville results support manufacturer claims for allergen reduction, only cat dander was measured, and tests were conducted in a controlled clean room environment - hardly the conditions of the average home.

Vacuum performance under real-world conditions were studied in 1998 by French researchers at the University of Strasbourg Hospital. They compared HEPA, HEPA/water, foam fabric filter vacuums, and standard vacuums. Five different vacuums were tested in an apartment with cats. The HEPA and HEPA/water filter vacuums blew out significantly less airborne dander than the foam filter and standard vacuums.

Microfilter dust bags: better than nothing

As might be expected, retrofitting your existing vacuum cleaner with a microfilter dust bag is not the best solution. Studies show that effectiveness can vary wildly from maker to maker. The 1999 Charlottesville study tested single-ply, two-ply, and three-ply microfiltration bags along with HEPA vacuums. The single layer bags performed “poorly” regardless of manufacturer. The double layer bags were more efficient than singles, but the results were inconsistent. Triple-ply bags proved to be the best of the lot. Before you choose a microfiltration bag for a standard vacuum cleaner, check out the number of layers.

The last word on vacuuming for allergen control

No single environmental control technique is going to handle indoor allergens all by itself. That’s one of the reasons some doctors are still reluctant to recommend HEPA vacuums, even though the AAAAI believes they can help. “Help” is the operative word. In other words, using a HEPA vacuum should not be the only environmental control step you take. Vacuuming alone is not enough - it’s most effective when combined with other techniques for reducing indoor allergens.

For example, allergists recommend reducing humidity to control dust mite populations. One 1999 study showed that vacuuming with a HEPA vacuum made humidity control efforts more effective. Researchers at the University of Southampton School of Medicine Allergy and Inflammation Sciences Division in the United Kingdom, outfitted the homes of forty dust mite sensitive asthma patients with central air conditioning, and gave ten of them HEPA vacuums. Household mite content was measured for a full year. While controlling humidity with the air conditioning system reduced mite populations, the addition of a HEPA vacuuming regimen made humidity control even more effective.

If changing your housekeeping habits seems like too much trouble, keep in mind that avoiding exposure to indoor allergens is the number one recommended treatment for both allergies and asthma. Ridding your indoor air of symptoms-provoking allergens means looking at the big picture. Isn’t it time to start controlling allergies or asthma - instead of letting them control you?

This entry was posted on Sunday, March 25th, 2007 at 1:38 am and is filed under Healthy Breathing. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.