Mold & Fungi

Mold is the common name given to various varieties of fungi involved in microbial contamination. Spores vary in concentrations in indoor and outdoor environments, making it difficult to establish exposure limits. One thing is certain: detection of mold is normal, it becomes a problem when the presence of active colony growth occurs.

Buildings are perfect habitats for mold growth. They have lots of sources of food--everything from cellulose-based products to flaked skin will do. They have the appropriate temperature range--from 40-100 degrees F, and lots of dark crevices, nooks and crannies. And mold loves HVAC systems. Ductwork and ceiling plenums, aided and abetted by fresh air intakes and fans blowing air around a building, are tailor-made conduits for microbes--not to mention bacteria, like legionella, and volatile organic compounds. HVAC systems unwittingly send out armies of airborne microscopic spores into occupied spaces, where they can hit their unsuspecting human marks--primarily through inhalation. HVAC systems are also capable of sucking moist air into a building and then shutting down before the air is properly dehumidified.

Some fungi have been known to produce toxins that are harmful to animals and humans when ingested, inhaled or in contact with the skin. The fungi that produce toxins are known as toxigenic fungi. A fungus that has increasingly been linked to building related problems is Stachybotrys chartarum. Stachybotrys chartarum is common in nature, grows on cellulose-rich plant materials--and has often been found water-damaged building materials, such as ceiling tiles, wall paper and sheet-rock, and cellulose resin wall board. These products can be found residential and commercial buildings.

Stachybotrys is not the only problematic fungi species found in moisture prone areas of homes and buildings. Other hazardous species include: Penicillium, aspergillus, and fusarium. Indoor air quality related problems are often the result of live fungus colonies in buildings. Almost without exception, these buildings have a history of chronic moisture problems.

Proper investigation with instrumentation can locate trapped moisture that could be a hiding place for mold growth. Mold growth can be abetted by a number of factors, alone or in combination, including faulty design, construction, inspection, commissioning, operations and maintenance. Natural disasters--floods and storms--and freak accidents like sewage leaks, which are nearly impossible to protect against, can also trigger mold growth.