Dehumidification: The Allergy Sufferer's Secret Weapon

Mold & Dust Mites. They're the two most pervasive indoor allergens, and if you suffer from environmental allergies, there's a good chance that you're sensitive to either mold or dust mites - or both.

With mold being a fungus and the dust mite being an arachnid, they don't seem to have much in common at first. However, recent research at the University of California (San Francisco) revolves around the fact that both mold and dust mites contain the compound chitin. Molds have chitin in their cell walls, and dust mites have chitin in their exoskeleton. Chitin is also found in the exoskeleton of highly allergenic animals like cockroaches, shrimp, and other shellfish. Researchers are still in the early stages, but they may find that chitin plays a key role in triggering the inflammatory response.

Mold and dust mites have something else in common, too:

They both thrive in humid climates.

"Humidity promotes mold growth and dust mite population growth," says Dr. Michael Ruff of the American Academy of Allergy Asthma and Immunology (AAAAI). "Both are significant indoor allergens and can set off allergic sensitivity and can trigger rhinitis and asthma."

Luckily, neither mold nor dust mites can survive well when the relative humidity drops below 45 percent. Dehumidification, therefore, is the allergy sufferer's secret weapon - especially during the warm months when humidity peaks.

What is Relative Humidity?

Relative humidity is the ratio of the amount of water vapor in the air to the maximum amount of water vapor that could be present. A relative humidity of 100 percent would indicate the dew point, where water vapor condenses to form water droplets. A relative humidity of 50 percent means that the air is holding only half of the water vapor that it could.

How to Control Your Relative Humidity

First, you need a way of measuring your relative humidity. A humidity gauge (or hygrometer) measures the relative humidity.

To curb the growth of mold and dust mite populations, you should keep the relative humidity below 45 percent.

If you find that your relative humidity is above 45 percent, you can remove moisture from the air using a dehumidifier. You may find that certain rooms (like basements) may be more humid than others.

Sometimes, usually during the winter, the relative humidity may drop too low, making the air dry and uncomfortable (especially for people with sinus problems). You can increase the amount of moisture in the air with a humidifier. If you use a humidifier, keep an eye on the relative humidity so that you don't cause a population explosion for mold and dust mites. Also be sure that the humidifier has some type of antimicrobial safeguard to prevent the growth of mold and bacteria - and clean it frequently!

Humidity & Dust Mites

Dust mites require humidity for survival because they absorb their moisture from the air. As the relative humidity increases, dust mites flourish; they reproduce more, eat more, and generate more sneeze-inducing fecal pellets. Conversely, they also lose moisture through their skin, and so they're quite vulnerable to dehydration.

According to University of Kentucky Entomologist Michael Potter, optimum conditions for dust mite growth and development are around 75-80 degrees Farenheit and 70-80 percent relative humidity, and dust mites cannot survive well at relative humidities below 50 percent.

Your bed provides not only warmth, but also plenty of moisture via your breath and perspiration, as well as food for dust mites in the form of your dead skin. Your bed is a haven for dust mites; that's why it's important to cover your mattress and pillows in Allergy Armor™ dust mite encasings that zip up to trap dust mites inside, cutting them off from their food source.

Because it absorbs moisture, carpet is also a haven for dust mites. Kill dust mites and deactivate their allergens in carpets with dust mite powders & sprays.

Humidity & Mold

The Asthma and Allergy Foundation of America (AAFA) recommends keeping the relative humidity below 45 percent to prevent mold growth. Use a humidity gauge to measure the relative humidity and a dehumidifier to lower the humidity.

Certain rooms tend to be more conducive to mold growth. We've all seen mold growing in a bathroom, for instance. Certain closets and cabinets may also provide an ideal environment for mold. Eva-Dry Mini Dehumidifiers work well in small spaces, and they absorb moisture without using electricity. M-1 House Wash and M-1 Sure Cote Sealant will help you clean up and prevent mold growth.

If you're allergic to mold, be sure to wear a mask, gloves, and non-vented goggles when cleaning up mold - and try to clean problem areas frequently to prevent build-up. If the mold growth is substantial (more than what you might see growing in a typical bathroom, for example), or if you suspect that it may be toxic mold, you should call a professional mold remediation service. Basements are notorious for mold growth. If you smell a musty odor in your basement, you're most likely inhaling mold spores. Dehumidification will vanquish the mold as well as the unpleasant odor. It's also important to keep the air moving inside your home. Fans, air conditioners, and air purifiers all help control mold growth. The most dangerous type of mold appears in standing water after leaks and floods. Standing water provides an environment for the toxic mold Stachybotrys, also known as black mold. You should repair any leaks immediately, no matter how small. The most damaging mold often grows for weeks, months, or years out of sight, behind a wall, or in a basement or closet, unbeknownst to all. Small leaks that go unnoticed are the most dangerous type. The Water Alarm allows you to detect leaks before mold growth or water damage can occur. Place water alarms in basements, under sinks, under water heaters, and wherever leaks may go unnoticed. After the sensors detect water, a loud alarm sounds at 110 decibels for up to 72 hours. Since you already have fire alarms your home, it only makes sense to have water alarms - because your home is actually 85% more likely to be damaged by water than fire.

In nature, mold plays a key role in the ecosystem by breaking down decomposing organic matter - but in your home, mold is an agent of allergy, infection, and destruction. High humidity promotes the growth of mold and dust mites, draws other pests, causes building materials to rot, and may destroy the structural integrity of your home. Humidity control, then, is not only a simple method of allergy relief; it's also a wise investment in your health and your home.

Originally featured in the June 2007 issue of Allergy Consumer Report.

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