| P. Heinsohn, Micro Bios, Pacifica, CA
Previous investigators identified fungal growth within exterior wall cavities of a multiple story apartment complex during their destructive testing (DT). These investigators either collected no air samples, collected spore trap air samples incapable of distinguishing between Penicillium and Aspergillus, and/or collected tape lift samples for which speciation is seldom possible.
The purpose of this study was to determine in other apartments if the indoor air quality (IAQ) were degraded with respect to fungi, and if hidden fungal growth in wall cavities was causally related to degraded IAQ.
The methods of investigation included: an informed inspection; air sampling for culturable and total fungal spores using an Andersen N-6 sampler and Zefon Air-O-Cell cassettes, respectively; and bulk sampling for fungi using multiple sampling methods. Full speciation was requested for all culture analysis, including samples taken of contents. DT with full containment was also performed in two apartments without visible fungal growth. The criteria used for interpretation of the data are those published by the American Industrial Hygiene Association (1996).
For one apartment, the IAQ was degraded by Penicillium brevicompactum as indicated by Andersen data and Penicillium/Aspergillus using Zefon data. Contents were contaminated at low concentrations of Penicillium chrysogenum. Despite growth of various fungi on exterior gypsum sheathing, including Stachybotrys chartarum, neither Penicillium brevicompactum nor Penicillium chrysogenum were found growing in the wall cavity. There was also no correlation between fungi growing in wall cavities and the fungal ecology of the occupied spaces in the second apartment. These data demonstrate that fungal growth in exterior wall cavities does not necessarily impace the IAQ of the occupied spaces or result in contamination of contents. | 