Concern about indoor exposure to mould has been increasing as the public becomes aware that exposure to mould can cause a variety of health effects and symptoms, including allergic reactions. Moulds can be found almost anywhere. They grow on virtually any organic substance, as long moisture and oxygen are present. There are moulds that can grow on wood, paper, carpet, foods and insulation.
Mould growth occurs when excessive moisture accumulates in buildings or on building materials, particularly if the moisture problem goes untreated. Air conditioning systems provide an excellent environment for mould growth. The cooling coil, which cools the air, has moisture, a cool temperature and dust particles for food. All air passes through this coil and, in many cases, over bacteria and mould. It is impossible to eliminate all moulds and mould spores in an indoor environment. However, mould growth can be controlled by controlling moisture and applying biocides to air conditioning coils.
Moulds reproduce by making spores that usually cannot be seen without magnification. Mould spores waft through the indoor and outdoor air continually. When mould spores land on damp spots, they begin to eat whatever they are growing on in order to survive.
There are many types of moulds, and they all have the potential to cause health effects. Moulds can produce allergens that trigger allergic reactions or asthma attacks. Others are known to produce potent toxins, irritants or both. Potential health concerns are an important reason to prevent mould growth and to clean up any existing mould growth.