| Populations and Determinants of Airborne Fungi in Large Office Buildings H. Jasmine Chao, Joel Schwartz, Donald K. Milton, and Harriet A. Burge Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA Abstract
Bioaerosol concentrations in office environments and their roles in causing building-related symptoms have drawn much attention in recent years. Most bioaerosol studies have been cross-sectional. We conducted a longitudinal study to examine the characteristics of airborne fungal populations and correlations with other environmental parameters in office environments. We investigated four office buildings in Boston, Massachusetts, during 1 year beginning May 1997, recruiting 21 offices with open workstations. We conducted intensive bioaerosol sampling every 6 weeks resulting in 10 sets of measurement events at each workstation, and recorded relative humidity, temperature, and CO2 concentrations continuously. We used principal component analysis (PCA) to identify groups of culturable fungal taxa that covaried in air. Four major groupings (PCA factors) were derived where the fungal taxa in the same groupings shared similar ecological requirements. Total airborne fungal concentrations varied significantly by season (highest in summer, lowest in winter) and were positively correlated with relative humidity and negatively related to CO2 concentrations. The first and second PCA factors had similar correlations with environmental variables compared with total fungi. The results of this study provide essential information on the variability within airborne fungal populations in office environments over time. These data also provide background against which cross-sectional data can be compared to facilitate interpretation. More studies are needed to correlate airborne fungi and occupants' health, controlling for seasonal effects and other important environmental factors. Key words: airborne culturable fungi, indoor air quality, longitudinal exposure assessment, office environments, principal component analysis (PCA) . Environ Health Perspect 110:777-782 (2002) . [Online 14 June 2002] http://ehpnet1.niehs.nih.gov/docs/2002/110p777-782chao/ abstract.html Address correspondence to H.J. Chao, Department of Environmental Health, Harvard School of Public Health, Building 1 Rm. G28, 665 Huntington Ave., Boston, MA 02115 USA. Telephone (617) 432-3965. Fax: (617) 432-3349. E-mail: jasmine@hsph.harvard.edu We thank M. Muilenberg and E.-C.J. Lee for their assistance in the intensive field and laboratory work. This project was supported by the U.S. Environmental Protection Agency (R824797) as part of the grant "Bioaerosols, Health and Productivity in Large Office Buildings." Received 5 September 2001 ; accepted 30 January 2002.
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