Toxic moulds and indoor air quality

Indoor air quality issues associated with exposure to moulds and their metabolites, mycotoxins, are becoming of increasing importance. There are believed to be about 1.5 million species of fungi of which more than 1000 species have evolved to exploit the built environment. Sexually mature fungi produce large numbers of spores that when airborne can be inhaled and deposited on the mucosal surface of the upper airways and in the eyes. Occupants of buildings may be affected in any of a number of ways. Fungi and moulds can contribute to the sick building syndrome or other building related illnesses and some people can have an allergic response. Such exposure to moulds and the other fungi and their spores indoors is unavoidable except when the most stringent air filtration or other environmental measures are observed. The repeated exposure to large amount of particular fungal propagules is an important risk factor for the development of specific allergic reactions. There are also a large number of toxic mould metabolites which can have a range of biological activities. Black Mould (Stachybotrys chartarum), in particular has been implicated in illnesses associated with living in damp houses. Reactions may be severe as in recent reports of idiopathic pulmonary haemorrhage in very young children in Cleveland, Ohio. Although some governmental agencies have published guidelines on mould assessment and remediation most are very general in nature and most focus on Black Mould as the major concern.