|Scott Armour, MS Environmental Health Science via ISEAI Members <firstname.lastname@example.org>||3:02 PM (7 minutes ago)|
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I wholeheartedly agree Michael, there is great difficulty, fear, pain and anguish associated with misplaced recommendations to “get rid of” all contents that are “porous”… or, to “get out” of the house, etc.
We have yet to see an ENVIRONMENTAL explanation of what is causing so many of the symptoms and illnesses. There is little environmental explanation or data from the original sources of these sweeping recommendations. We still need to consider and understand the full effect, and more importantly the required dose, of compounds like cell wall components (e.g., glucans), VOC’s (of which there are over 1000 from bacteria and molds), and mycotoxins (of which there are over 300). Not to mention the “simple” irritation effects and allergenic effects.
The environmental process should be, as Michael alludes to, a step-wise assessment and step-wise remediation and cleaning. Each step leads to new findings and better understanding; this permits us to manage within reason the costs, resources, and impacts both positive and negative, on the occupants and building.
The most important consideration for the environment is the actual active growth in the living space. This means there is a sufficient provision of water (in the form of either liquid or vapor or both) to keep the mold continually growing, sporulating, metabolizing, and reproducing. These life activities produce at least four sources of illness: VOC’s (metabolism), Spores (sporulation and reproduction), cell wall components (growth), and Mycotoxins (growth with need to expand and protect the structure). The fifth illness would be actual pathogenic or infection, but, curiously, infection (e.g., aspergillosis) is not correlated with water damaged buildings; hence, we can safely ignore this risk of infection in the typical building environment and occupant assessment for mold impact. (I will not address HAI’s or likely susceptible populations for infection.)
The next most important factor in the building is “old dead” mold. It has no source of water, is not living nor reproducing nor metabolizing. However, the structures remain somewhat intact and even if desiccated or broken into fragments, the molecular compounds that cause illness are not damaged or altered when “dead”. In the “dead” state, at least three, if not four, of the components impacting health: the same as above but less airborne (intentional) release of VOC’s and spores. Disturbance of the growth will release some or all four into the air. Cell wall compounds and mycotoxins are released as part of the crumbled fragments, not as individual molecules like the VOC’s. Spores are found in various configurations: clumps, chains, solo; and all can be light enough to become airborne when surface is disturbed.
(Note: VOC’s include odor/fragrance; often, the “mildewy, musty” odor lingers long after mold is dry and dead. I have no clear explanation, except that these volatile and semi-volatile molecules are “trapped” within the matrix of the growth structures and possibly any associated bio-film or other substrate. From this we can safely assume that non-detectable VOC’s are similarly released over time from dead dry mold.)
The lease important factor to the occupant is the “invisible” contaminant, what I often call the “mold dust”. This includes the loose spores, mycelial fragments and growth structures that have been distributed into the ambient air and settled on surfaces to become part of the ambient background dust. These are the particulates not directly associated with actual identifiable visible growth. In the ANSI/IICRC S520 Professional Mold Remediation Standard the settled mold dust is termed Condition 2. Condition 1 is the normal fungal ecology in a non-damaged building; Condition 3 is the actual visible growth.