Assessment of exposure to bioaerosols in "sick" and "healthy" buildings

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Project Period: 
Project Investigator(s): 
PS Thorne, J DeKoster, Institute of Agricultural Medicine and Occupational Health, Department of Preventive Medicine and Environmental Health, The University of Iowa

This study characterized the levels of bioaerosol contamination of indoor air environments. Significant findings of the study include: 1) Fungi and respirable bacteria concentrations were significantly higher in basements, while CO2 levels were higher on the main floor; 2) Healthy homes had indoor viable fungal concentrations 30 to 50% of the outdoor levels, whereas sick homes had levels over 60%. Strong seasonal effect was seen from measurements of outside fungi but this was not reflected in indoor concentrations; 3) CO2 concentration was not associated with bioaerosol concentration; basement relative humidity was associated with increased airborne fungi; central air conditioning and increased air conditioner use were associated with lower microbial concentrations; lower Penicillium and Aspergillus airborne spores were associated with high efficiency furnace filters; and homes with finished basements had significantly lower microbial concentrations; 4) Tests of association using survey results showed age of occupant and the presence of smokers in the house to be significantly associated with increased self-reported health symptoms, including watery eyes, drowsiness, backaches, muscle/joint pain, indigestion, nausea, and flaky skin; and 5) Methodologies using the Anderson microbial sampler and the Burkard spore sampler demonstrated excellent agreement between theses two methods of air sampling.


DeKoster JA, Thorne PS; Bioaerosol Concentrations in Noncomplaint, Complaint, and Intervention Homes in the Midwest. American Industrial Hygienic Association Journal. 1995; 56:573-580