Mold and Dust Mites are
the two most pervasive indoor allergens. If you suffer from environmental allergies, there
is a great chance that you are sensitive to either mold or dust
mites - or both.
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
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
According to University of Kentucky Entomologist Michael Potter, optimum conditions for dust mite growth and development are around 75-80 degrees
and 70-80 percent relative humidity, and dust mites cannot survive well when the relative humidity is 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.