Mold, Mildew and Bacteria
Mold, mildew and bacteria are all biological pollutants found in most homes. And though it is impossible to rid your home of all of them, an increasing number of consumers are opting for mold testing and inspection to get a better handle on the extent of their presence and how to minimize their growth in the home. A mold test or mold inspection can help identify the type of mold that may be present in your home, but it can not guarantee your home is mold-free or will not develop mold at a later time. Generally a mold test will sample existing mold and test the mold to identify the species or type. However, homeowners or homebuyers may opt to avail themselves of additional more expensive, albeit more detailed testing or inspections. Additional testing or inspection can often identify mold types that may increase the likelihood that the home's inhabitants experience adverse health affects as a result of the exposure.
It is impossible to rid your home of all biological pollutants. Your goal should be to recognize the causes and signs of these pollutants and to minimize or eliminate their entry or stay in your home. All of us are exposed to these pollutants; however, their effects on our health depend upon the type and amount of the pollutants present. Some people do not experience any adverse health reactions from certain pollutants while others may react moderately or worse from the same exposure. Individuals at both ends of the age spectrum (the elderly and newborn) or with compromised immune systems or respiratory problems are more vulnerable.
Before we look into ways of controlling these biological pollutants, let's look at what we are dealing with. Mold and mildew are one-cell plant-like organisms that are of the Kingdom Fungi - microorganisms that lack chlorophyll and vascular tissue. This Kingdom includes the yeasts, molds, mildew, and mushrooms. There are differences between mold and mildew, but the concerns are similar.
Mold grows from spores which are everywhere in our environment. Usually these spores are inactive, but will germinate when the relative humidity exceeds 70 percent. Mold attacks organic materials such as paper, books, cloth, photographs, and leather. Mildew is more a surface concern, growing on walls, siding, and other surfaces covered with a film of dirt containing organic matter that has been exposed to moisture. Temperatures above 65°F (18°C) increase the likelihood of mold or mildew. Signs of mold and mildew include growths, discolored surfaces and odors. Homes exposed to flooding, water penetration or leakage problems, and/or high humidity conditions are especially susceptible.
Bacteria, another microorganism, can contaminate an air conditioning system or other moisture-laden areas. Bacterial growths account for most of the slime that clogs air conditioner drain pans and drain lines. Bacteria create the initial tacky coating on heat transfer surfaces that catch and hold dust and fibers, which can eventually lead to clogged coil passages.
There are no simple, inexpensive methods of uncovering fungi or bacteria conditions in a home. But once a biological pollution condition is discovered, there are means to identify its cause and to eliminate it. Certain catastrophic events, such as flooding or serious water intrusion, are certain to quickly lead to mold conditions unless prompt remedial action is initiated.
A home inspection does not include a specific investigation or identification of any environmental concerns including mold, mildew and bacteria. If there are concerns about the presence of molds, particularly if related to personal health factors, a qualified environmental specialist should be consulted for information on available inspection services.
Fungi and bacteria require moisture to survive. To minimize the chances of your home becoming a breeding ground for any fungus or bacterium, you must address conditions that contribute to water penetration and high humidity conditions. Here are some general recommendations to control moisture and help prevent the growth of fungi or other biological pollutants:
- Humidifiers (particularly reservoir, non-misting types) can promote mold and mildew growth and help spread spores throughout the house if not properly maintained. These units must be serviced regularly.
- Condensate collection pans under the indoor coil for air conditioning units provide a perfect environment for bacteria. Check and, if accessible, thoroughly bleach-clean them as needed.
- Ground water that is not directed away from your home may penetrate the foundation and/or the crawlspace walls and will provide mold and mildew spores with the moisture they require to thrive. Pipe downspouts away from the house, maintain a positive grade around your foundation, and address any water penetration conditions immediately.
- Faulty or missing flashings allow rainwater to enter your home and settle in hidden areas such as attics and insulated roof or wall cavities. Check and maintain flashings annually.
- Unfinished, dirt-floor crawlspaces allow ground moisture to rise and permeate house framing and insulation. Such crawlspace surfaces should be sealed by placing polyethylene sheeting over them and taping all seams and edges. Keep crawlspaces well ventilated.
- Bathrooms and laundry areas, particularly if unventilated or poorly ventilated, encourage the growth of mold and mildew. Venting (including bathroom exhaust vents as well as dryer vents) should be piped to the outside and not to an interior area such as an attic or garage.
- Improperly vented fuel-burning appliances can raise the relative humidity in a room. Shut off offending appliances at first signs of condensation on windows or other surfaces and check venting systems to ensure all potentially harmful flue gas exhausts to the exterior.
- Dehumidifiers and air conditioning can be used, especially in hot, humid areas, to draw moisture out of the air. Be sure these appliances don't themselves become sources of biological pollutants.
- Major systems, such as furnaces, heat pumps and central air conditioners, should be inspected and cleaned annually before seasonal use.
- Before using duct cleaning services, confirm there is a need and verify that the contractor will provide protection from dislodged pollutants and chemicals used in the cleaning process.
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