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Mold and Mildew
No one likes mold and mildew. Even if you aren't allergic to it mold is dirty, slimy, smelly, and just plain unhealthy. It's not good for the house or construction materials either. Mold grows because of excess humidity, which can get into the wood, drywall, flooring, or siding of a house, and eventually can cause rot and decay.
Mold thrives in damp, dark, poorly ventilated places. Look for its presence in closed closets, musty or damp bathroom crevices, behind wallpaper, on moist walls or windowsills, or even on the ceiling in areas where the roof leaks. During hot and muggy weather, mold can even form on books, stacked magazines, in the clothes hamper, or on bathroom towels.
Molds in Indoor Air
Concern about indoor exposure to mold has been increasing as the public becomes aware that exposure to mold can cause a variety of health effects and symptoms, including allergic reactions.
Molds can be found almost anywhere; they can grow on virtually any organic substance, as long moisture and oxygen are present. There are molds that can grow on wood, paper, carpet, foods, and insulation. When excessive moisture accumulates in buildings or on building materials, mold growth will often occur, particularly if the moisture problem remains undiscovered or unaddressed. It is impossible to eliminate all molds and mold spores in the indoor environment. However, mold growth can be controlled indoors by controlling moisture indoors.
Molds reproduce by making spores that usually cannot be seen without magnification. Mold spores waft through the indoor and outdoor air continually. When mold spores land on a damp spot indoors, they may begin growing and digesting whatever they are growing on in order to survive. Molds gradually destroy the things they grow on.
Many types of molds exist. All molds have the potential to cause health effects. Molds can produce allergens that can trigger allergic reactions or even asthma attacks in people allergic to mold. Others are known to produce potent toxins and / or irritants. Potential health concerns are an important reason to prevent mold growth and to remediate / clean up any existing indoor mold growth.
What Causes Molds
Since mold requires water to grow, it is important to prevent moisture problems in buildings. Moisture problems can have many causes including uncontrolled humidity. Some moisture problems in buildings have bee linked to changes in building construction practices during the 1970s, 80s, and 90s. Some of these changes have resulted in buildings that are tightly sealed, but may lack adequate ventilation, potentially leading to moisture buildup. Building materials such as drywall, may not allow moisture to escape easily. Moisture problems may include roof leaks, landscaping or gutters that direct water into or under the building, and unvented combustion appliances. Delayed maintenance or insufficient maintenance is also associated with moisture problems in schools and large buildings. Moisture problems in portable classrooms and other temporary structures have frequently been associated with mold problems.
Why Mold is Bad For Your Health
When moisture problems occur and mold growth results, building or home occupants may begin to report odors and a variety of health problems. Once a mold begins to bloom, it quickly matures and sends spores floating throughout the structure to be breathed by everyone who comes in contact with it. Reported symptoms can include those such as headaches, breathing difficulties, skin irritation, allergic reactions, and aggravation of asthma symptoms. People who are sensitive to a fungus report that even a tiny amount causes discomforts in the form of sneezing, watery eyes, coughing, shortness of breath, dizziness, lethargy, fever, and digestive problems. Some allergic reactions are the result of a previous exposure that a person may not have been aware of. As a result, people who have noticed only mild allergic reactions, or no reactions at all may suddenly find themselves very sensitive to particular molds.
All molds have the potential to cause health effects. Molds produce allergens, irritants, and in some cases, toxins that may cause reactions in humans. The types and severity of symptoms depend, in part, on the types of mold present, the extent of an individual's exposure, the ages of the individuals, and their existing sensitivities or allergies. Specific reactions to mold growth can include:
- Allergic reactions that can include sneezing, runny nose, red eyes, and skin rash.
- Asthma attacks in persons who are allergic to molds.
- Hypersensitivity Pneumonitis, which is similar to bacterial pneumonia and is uncommon
- Opportunistic infections that attack people with weakened immune systems (immune-compromised, immune-supressed) that may be more vulnerable to infections by molds.
Molds can produce toxic substances called mycotoxins. Some mycotoxins cling to the surface of mold spores, others may be found within spores. More that 200 mycotoxins have been identified from common molds. Many symptoms and human health effects attributed to inhalation of mycotoxins have been reported including: mucous membrane irritation, skin rash, nausea, immune system suppression, acute or chronic liver damage, acute or chronic central nervous system damage, endocrine effects, and cancer. More studies are needed to get a clear picture of the health effects related to most mycotoxins. However, it is clearly prudent to avoid exposure to molds and mycotoxins.
The key to mold control is moisture control. Solve moisture problems before they become mold problems!
Some tips to help you get a jump on preventing mold include:
- Fix leaky plumbing and leaks in the building envelope as soon as possible
- Watch for condensation and wet spots. Fix source(s) of moisture problem(s) as soon as possible
- Prevent moisture due to condensation by increasing surface temperature or reducing the moisture level in air (humidity). To increase surface temperature, insulate or increase air circulation. To reduce the moisture level in air, repair leaks, increase ventilation (if outside air is cold and dry), or dehumidify (if outdoor air is warm and humid).
- Keep heating, ventilation, and air conditioning (HVAC) drip pans clean, flowing properly, and unobstructed.
- Vent moisture-generating appliances, such as dryers, to the outside where possible.
- Maintain low indoor humidity, below 60% relative humidity (RH), ideally 30-50%, if possible.
- Perform regular building / HVAC inspections and maintenance as scheduled.
- Clean and dry wet or damp spots within 48 hours.
- Don't let foundations stay wet. Provide drainage and slope the ground away from the foundation.
When mold growth occurs in buildings, some building occupants, particularly those with allergies or respiratory problems, may report adverse health problems. Those trying to clean up molds should avoid exposing themselves and others to mold-laden dusts as they conduct their cleanup activities. Caution should be used to prevent mold and mold spores from being dispersed throughout the air where they can be inhaled by building occupants.