Do damp and mould matter? Health impacts of leaky homes. Howden-Chapman P; Bennett J; Siebers R, eds., Wellington, N.Z.: Steele Roberts Pub., 2009 Jan; :49-60
The air we breathe contains a heterogeneous mixture of particles from nonbiological and biological sources; the latter being derived from plants, fungi, microbes and animals. Such particles can either be biologically destined for dispersal, such as pollen grains, fungal spores, or aerosolised viruses, or are the products of natural breakdown, such as plant and fungal fragments, animal dander, insect detritus and carpet fibres when indoors. These bioaerosols range in size from less than one micrometre to greater than 100 micrometres and vary greatly in shape, density and other features that may influence airborne dispersal, adhesion and behaviour. The vast majority of these particles probably have little effect on health when normally inhaled by people, but identifying and understanding the chronic and acute health effects of the few that do, and the relationship of such exposure to disease pathology, is one of the continuing challenges associated with the field of exposure assessment. In our laboratory we have focused on the development of analytical techniques to collect and detect aero allergen sources, in particular airborne fungi; one of the most ubiquitous indoor, outdoor and occupational bioaerosols. In indoor environments, fungal spores and hyphae are derived from either outdoor sources coming into buildings as components of natural ventilation, or those that have their origin inside the building envelope as a consequence of growth on damp building materials. Typically abundant sources include Alternaria, Aspergillus, Chaetomium, Cladosporium, Penicillium, Stachybotrys and Malassezia. Certain species belonging to these genera have been acknowledged as the etiological agents responsible for exacerbations of various respiratory and dermatological diseases. Although health effects associated with damp and mouldy dwellings have been suggested since Biblical times, interest in the pathogenic mechanisms as well as the public and legal concerns has driven exposure assessment as a research priority. An example of this interest is the Institute of Medicine's comprehensive report on damp indoor spaces and health. However, the scientific understanding of fungal exposure in these environments has been limited, in part, by methodological difficulties in identifying and detecting fungal components in environmental samples. This includes identifying components that are allergen sources, such as hyphal fragments and sub-cellular particulates.