Moisture-Happy Molds and Microbes

Fighting mold and mildew in the bathroom can become a constant battle, especially when inadequate ventilation prevents moisture from drying rapidly. Just imagine if you had to worry about mold in the rest of your house. Most of us don't really think about it until we see or smell it. But mold and other fungi can grow just about anywhere there is moisture, hidden away in ventilation systems, behind walls, and in basements.

Molds are certainly unsightly and can be a health hazard. That distinctively unpleasant musty odor of mold comes from the gasses emitted as a byproduct of the growing mold. In addition to breathing these gasses, you and your family can inhale mold particulates and spores. Both can cause health problems such as respiratory infections, allergic reactions, irritability, and headaches. One class of fungi, called mycotoxins, has toxic effects ranging from short-term irritation to immunosuppression and cancer. Various types of mold spores can settle into a damp spot in your home, some more harmful than others. In 1993, the U.S. Centers for Disease Control and Prevention linked bleeding lung syndrome, or pulmonary hemorrhage, in ten Cleveland, Ohio, infants to a toxic mold, Stachybotrys atra, found in flood water left standing in homes. Eight of the ten infants died from related illness. Since then, this mold has been discovered in schools and libraries around the country, including the Tottenville Library in Staten Island, New York. In the fall of 1997, the library was closed after a black mold within its walls and ventilation systems was linked to skin rashes, heart palpitations, respiratory problems, headaches, and chronic fatigue among employees. This type of mold occurs infrequently, but you may be harboring other molds in your house that might cause fatigue, headaches, or sneezing.

Moisture can also encourage the growth of other harmful microbes, such as dust mites and bacteria. Inadequate ventilation and high humidity may increase transmission of other viral and bacterial illnesses. And moisture attracts insects, from roaches to termites.

If your home is airtight, moisture from showers, cooking, dishwashing, and doing laundry can build up. Even humans add moisture to indoor air from respiration and perspiration. But if the overall humidity level in your home is not high, you may still have problems with mold when water dampens something in your home, from wicker baskets to garbage and diaper pails. Dirty laundry, stuffed animals, fabric furnishings, carpets, and houseplants can also host mold colonies. Plumbing may leak and moisten plaster and wood in walls, ceilings, and floors, leading to mold growth inside wall cavities. Water may also seep into basements from soil because of lack of gutters or water flow towards the house.

Molds and bacteria may grow in air conditioners and humidifiers, then disperse when the machines are used, if they are not properly cleaned and maintained. Contamination of humidifiers is associated with hypersensitivity pneumonitis, a flulike respiratory illness, and humidifier fever, which is also flulike but without respiratory symptoms.

Preventing Mold Growth

Preventing mold growth is as simple as eliminating as many sources of water and condensation as possible. The tricky part is finding all of those places. Here are a few suggestions:

For more information, call EPA's Indoor Air Quality Hotline, the CPSC, and the American Lung Association for fact sheets and pamphlets on biological pollutants such as mold.

Cleaning Up Mold

Mold may be visible, but it often grows behind walls, in and under carpets, and inside upholstered furniture. Your only clue may be the odor or allergy symptoms, such as headache, runny nose, and fatigue. To be certain that your problem is mold, you can use a mold test plate, available from Allergy Resources. You can also have your home tested for mold by a local laboratory or environmental consultant listed in your telephone directory.

To kill mold, you must eliminate the moisture available to it. Once it no longer has water to live on, the mold will die on its own and won't produce more spores. A portable radiant heater will speed up the drying of walls, carpeting, and furnishings. Resist the temptation to use a hair dryer or fan; they will blow mold spores around, increasing the chance that a new colony will sprout. After you've dried up the mold, clean it up with soapy water. Even dead mold spores can cause allergic reactions in sensitive people, so be as thorough as possible. Avoid vacuuming up the mold-the spores will pass through the filters and waft back into the room-unless you have a specially equipped HEPA vacuum cleaner, which has a more effective filter. While you don't need a fungicide if you clean up well, borax, vinegar, or hydrogen peroxide (full-strength) kill mold spores effectively. Use one of these cleaners if the mold-infested wall or carpet will remain wet for an extended period of time. This will prevent continued mold growth. Once you've cleaned up, seek out the source of moisture that fed the mold colony and eliminate it to prevent a recurrence.

Some Notes on Humidifiers

During winter months when artificial heat contributes to an already arid environment, you and your baby might feel some discomfort. Dry conditions rob our bodies of moisture, causing skin, eye, and nasal irritation. Many people use humidifiers to increase humidity in their homes. Some also use them to help relieve nasal and chest congestion. But, as mentioned above, humidifiers can harbor mold and bacteria and spew them out all over the room. So we suggest you avoid them, if you can.

Try the following before resorting to a humidifier.

If, after you've tried these, you still feel a humidifier is necessary, choose one carefully-frankly, none are ideal. Steam humidifiers do kill microorganisms when water is boiled in the unit, but they can release minerals from tap water into the air as fine particles that settle as a powdery white dust that can irritate your lungs and even cause scarring. And it's not wise to use appliances that produce high heat around your infant. Many steam humidifiers have safety features, such as automatic shut-off when water level is low or the unit is tipped over. Cool-spray humidifiers avoid the problem of heat, but won't kill mold and bacteria and also release minerals. Some cool-spray humidifiers are equipped with ultraviolet light, which kills mold spores and bacteria, but these also emit minerals. Ultrasonic-dispersal humidifiers use high-frequency sound to break up minerals and microbes in water droplets before they are emitted. These particles are extremely fine and can be inhaled into the lungs, so it's best to avoid this type of humidifier. Don't use evaporative humidifiers, which work by blowing air across or through water-saturated foam or other material to cause evaporation. The foam will become a microbe factory without very careful attention.

Whatever type of humidifier you decide on, make sure that it is the right size for the room. One that has a large capacity will potentially inundate the room with moisture. Purchasing a humidifier with a humidistat, a device that will detect relative humidity levels and turn the humidifier off when a preset level has been reached, will eliminate the possibility of increasing moisture to mold-sustaining levels. You can also monitor humidity levels with a hygrometer, available in hardware stores and Radio Shack. The Consumer Product Safety Commission (CPSC) suggests maintaining the relative humidity between 30 and 50 percent, as levels above 60 percent increase the likelihood of mold growth.

CPSC recommends using distilled or demineralized water in humidifiers to reduce scale buildup (which can harbor bacteria) and the release of minerals from the humidifier. Clean humidifiers, using a brush to scrub off mineral deposits, at least as often as the manufacturer suggests or more. Change water daily, and do not allow water to sit in the tank for more than a few hours.

Excerpted from: Guideto Natural Baby Care, by Mindy Pennybackerand Aisha Ikramuddin