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Bacteria and fungi associated with insulated HVAC ducts in complaint buildings in the United States.
Sixth US-Finnish Joint Symposium on Occupational Health and Safety, People and Work, Proceedings of the Sixth FIOH-NIOSH Joint Symposium on Occupational Health and Safety, 8-10 August 1995, Espoo, Finland. People and Work - Research Reports 3. H. Nordman, J. Starck, A. Tossavainen, E. Viikari-Juntura, eds. Helsinki, Finland: Finnish Institute of Occupational Health; 1995 Aug; :119-122
The results of NIOSH studies of microorganism contamination of insulation materials used in heating, ventilation, and air conditioning (HVAC) systems were summarized. Sixty two samples of insulation materials cut from the ducts of HVAC systems obtained during 27 NIOSH environmental quality evaluations conducted in offices, factories, schools, libraries, or health care facilities conducted in response to employee complaints between April and July 1993 were assayed for bacteria, fungi, and thermophilic actinomycetes by standard microbiological procedures. Fifty one samples (82%) contained fungi, of which 63% were Penicillium species. Yeasts were isolated from ten of the fungi containing samples. Mesophilic bacteria were isolated from 29 of the samples (47%). Most of these samples had been collected downstream from the cooling coils. Bacillus-insolitis was the predominant species identified. Staphyloccocal and micrococcal species were isolated from some samples. Twelve samples (19%) contained thermophilic actinomycetes. The authors suggest that the high prevalence of Penicillium species detected in the samples implies that duct insulation acts as a common amplification site for this species, which is a soil organism and not commonly found at high concentrations in air. Climatic factors may have also influenced the microorganism profile. The authors further suggest that bulk samples should be obtained as part of a holistic approach to examining buildings with potential microbial contamination.
Microorganisms; Insulation-materials; Air-quality; Ventilation-equipment; Air-conditioning; Closed-building-syndrome; Indoor-air-pollution; Climatic-factors; Indoor-environmental-quality
Nordman-H; Starck-J; Tossavainen-A; Viikari-Juntura-E
Sixth US-Finnish Joint Symposium on Occupational Health and Safety, People and Work, Proceedings of the Sixth FIOH-NIOSH Joint Symposium on Occupational Health and Safety, 8-10 August 1995, Espoo, Finland. People and Work - Research Reports 3
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division