Abstract
Airborne concentrations of fungi were measured in six residential and office environments in response to health complaints. In each case, volumetric samples were collected at several locations using Andersen sieve samplers. Reference samples were collected outside all buildings. Swab samples of surfaces and bulk samples of materials such as carpeting and ceiling tiles were also collected and analyzed to determine possible sources of microbial contamination. Predominant fungi were identified based upon gross colony morphology and microscopic examination. Airborne concentrations of fungi detected inside each of the buildings significantly exceeded outdoor concentrations in at least one location, indicating indoor sources of contamination. The predominant types of indoor specific microorganisms detected implicated indoor sources. Swab and bulk samples verified sources. Contamination was caused by either water damage or buildup of dust. Fungi were aerosolized from contaminated materials by movement of air through contaminated fans, the ventilation system, the fireplace, or human activity. Effective reduction of airborne concentrations of fungi by remedial measures was demonstrated by follow-up air sampling.