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Facts About Mold AIHA® December 2011 9 Glucan: Glucans are polysaccharides comprised primarily of glucose present in plants and fungi. In buildings, both plant and fungal glucan are present. Different chemical forms of glucan have different effects on health. Some glucans are marketed as being good for health such as the glucans that come from mushrooms. The form of glucan that dominates in molds such as Aspergillus and Penicillium and related fungi is called beta‐1, 3‐D‐glucan in triple helical form. Triple helical glucan reacts to the glucan receptor in the lung, and this results in inflammatory processes being stimulated. Hidden mold: Visible mold growth on building structures that is not easily seen—for example, above drop ceilings, within wall cavities (the space between the inner and outer structure of a wall), inside air handlers, or within the ducting of a ventilation system. Visible mold within a ventilation duct is in immediate contact with the occupied space. Spores released from such growths are affected by air movement and relative humidity. Spores of mold growth in wall cavities are released by the air exchange between the wall cavity and occupied space. The rate of spore movement between such spaces is typically slow. Volatile gases produced by visible mold growth in wall cavities are also known to occur and migrate to occupied spaces even through air barriers. Microbial volatile organic compounds (MVOCs): Chemicals produced by fungi as a result of their metabolism. Some of these chemicals are responsible for the characteristic moldy, musty, or earthy smell of fungi, whether mushrooms or molds. Some MVOCs are considered irritants, and their presence is usually annoying. Specific MVOCs are thought to be characteristic of wood rot and mold growth on building materials. The human nose is very sensitive to mold odors, sometimes more so than current analytical instruments. Mold: A group of organisms that belong to the fungi kingdom (see Fungi). Although the terms mold and fungi have been commonly referred to interchangeably, all molds are fungi, but not all fungi are molds. Mycotoxins: Compounds produced by "toxigenic fungi" that are toxic to humans or animals. By convention, the term "mycotoxins" excludes mushroom toxins and compounds of low potency or toxicity only in in‐vitro systems. The ordinary use of the term refers to compounds of importance in agriculture. This includes a small number of very potent compounds such as deoxynivalenol, aflatoxin, fumonisin, ochratoxin, and zearalenone. It also includes the much less common nivalenol, T‐2/HT‐2 toxins, as well as some other Penicillium and Aspergillus toxins and toxins from Stachybotrys chartarum and Pithomyces chartarum. The biochemical targets of mycotoxins are usually many, but the mechanisms of toxicity, even within families of toxins, are typically different. It is important to remember that the toxins from agriculturally important fungi, including deoxynivalenol, aflatoxin, fumonisin, ochratoxin, T‐2 toxin and zearalenone, do not occur on building materials. The genetic property to produce mycotoxins is particular to given species. Some species including Fusarium graminearum and S. chartarum have genetic subpopulations called chemotypes that produce different mixtures of compounds. In the case of F. graminearum, these chemotypes are distributed by continent. In the case of S. chartarum, both chemotypes occur together. Remediate: To fix a problem. Related to mold contamination, remediation includes fixing the water/moisture problem and the cleaning, removal, and/or replacement of damaged or contaminated materials. Spore: General term for a reproductive structure in fungi, bacteria, and some plants. In fungi, the spore is the structure that may be used for dissemination and may be resistant to adverse environmental conditions.

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