There is a growing body of evidence on fungal contamination in moisture-damaged and complaint buildings worldwide, but little is known about the occurrence and distribution of fungi in healthy non-complaint buildings in a southern-hemisphere climate. The study tested the hypothesis that fungi in healthy buildings are low in numbers and very similar to the numbers and mixtures of species in both the outdoor air and the indoor air in other parts of the world. Fungi were collected using a 6-stage Andersen sampler, and various indoor air quality (IAQ) indicators and a sick-building syndrome (SBS) questionnaire were used in parallel. The results showed that all IAQ parameters were within USA and Canadian guidelines in all the buildings. There was also a low incidence of SBS complaints and symptoms. The total colony-forming unit (CFU) counts were also low, and the range of fungal species was low compared to buildings in other parts of the world. However, the mixture of fungal genera in the indoor air was different from the outdoor air. There were also substantial differences between indoor locations. At some locations fungi including Aspergillus niger, Penicillium spp. and Alternaria alternata were much higher indoors than outdoors or, as the pathogen Paecilomyces lilacinus, were absent in the outdoor air indicating indoor sources. Differentiation of fungal species was required to identify indoor fungal sources as the outdoor air was not the major source of indoor fungi. The study also demonstrated that evaluating the potential exposure to airborne fungi in indoor air requires differentiation to the species level as simple CFU counts could not differentiate between benign and potentially harmful fungi. Copyright 2002 S. Karger AG, Basel.
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