Mold is ubiquitous in nature, making up approximately 25% of the earth’s biomass, and thrives in many outdoor environments.
Molds, yeasts and other certain related forms constitute the organisms (microbial agents) known as fungi. We have all seen fungi growing on rotten fruit, bread and damp leather. They may by green, black or white and may appear to be fuzzy or sooty. Fungi are plant-like & many consist of two parts – hyphae, which are fungal filaments that form the body – and spores, which are seed-like structures than can be used for reproduction. Some spores contain mycotoxins and have been termed “toxic mold”.
Fungi must subsist on organic matter such as wood or paper products. In order for fungi to thrive, the following conditions are necessary: An ambient temperature range of 40-100 degrees F; a humid rich environment, generally greater than 60% humidity though usually greater than 70%.
Why is mold in real estate a potential concern?
I was once at a home inspection with noted indoor air investigator, Jeff May, and he gave me a copy of his book entitled “My House is Killing Me”. In it he says that mold causes four main types of illnesses in humans: allergies, irritation, infectious disease & toxic effects. Microbial agents may serve as irritants to the respiratory tract causing an increase in mucus flow and other types of symptoms. These agents may cause infections in two manners: pathogenic infection – this can develop in a relatively healthy individual with a normally functioning immune system; and opportunistic infection – this can develop in an individual with a compromised immune system or those with or on chemotherapy, diabetics, asthma or antibiotics, HIV or AIDS, physical or mental conditions affecting the immune system. Some factors responsible for the concerns are the ability of the agent becoming airborne in sufficient concentrations and the ability of the agent to be respired by the susceptible host.
Are there any buildings more vulnerable to mold growth?
Any dwelling with a history of current water infiltration problems as well as those structures with consistently high indoor humidity levels or those with poorly designed components such as inadequately vented attics and crawl spaces, as well as poorly designed or maintained HVAC systems.
How do I know if mold is present within a dwelling?
Mold growth should be suspected when surfaces are discolored i.e. “mildew” or if damp mildew odor is present which can represent mold by-products such as – microbial volatile organic compounds (or as I call it eau de mold). This is especially true on organic natural materials.
If mold growth is suspected what should be done?
A trained indoor environmentalist or mold remediation specialist should be consulted to determine the presence of mold, its cause and cure.
Are there any threshold limits in which mold is a concern?
Because all individuals have varying degrees of sensitivity to mold there are currently no threshold limit values.
What is toxic mold?
Toxic mold refers to certain mold species that have spores that contain mycotoxins such as stachybotrys, also called Black Mold. Mycotoxins are opportunistic pathogens and may be a greater health concern for certain individuals.
If mold growth is confirmed within the indoor environment what should be done?
Depending on the amount and depth of the mold growth, the solutions may range from removing surface mold via HEPA vacuuming and washing. To the extreme of removing and replacing all effected material, it is strongly suggested that only those with specific training and experience conduct any mold remediation work.
How can mold growth be prevented?
Mold requires several conditions to thrive. An organic material (wood or paper), oxygen, appropriate ambient temperature, a high moisture content and/or a high ambient relative humidity of 60% or greater. The most controllable factor of these conditions is the moisture content, which is usually controlled by removing moisture sources (water infiltration) and reducing and maintaining the indoor ambient humidity level to below 60%.
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