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Dustborne fungi in large office buildings
Hsing Jasmine Chao1, Donald K Milton, Joel Schwartz
1Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115, USA. jasmine@hsph.harvard.edu
Abstract:
Fungi are ubiquitous in our daily environments. However, their effects on office workers' health are of great interest to many environmental health researchers. Dust has been considered an important reservoir of indoor fungi from which aerosolization and exposure could occur. We have examined the characteristics of dustborne fungal populations recovered from floors and chairs in office buildings. We investigated twenty-one offices in four office buildings in Boston, MA over a year beginning May 1997. We conducted intensive environmental sampling every six weeks to measure culturable dustborne fungi from floors and chairs, surface dust levels and water activity in carpeting. Carbon dioxide, temperature, and relative humidity were monitored continuously. Concentrations of total dustborne fungi recovered from floors were positively related to carbon dioxide (beta = 0.00064; p-value = 0.0002) and temperatures between 20 and 22.5 degrees C (p-value = 0.0026). Also, total fungal concentrations in floors gradually increased over the year (p-value = 0.0028). Total fungi recovered from chairs varied significantly by season (p-value < 0.0001), highest in September and lowest in March, and were positively correlated with dust loads in floors (beta = 0.25; p-value < 0.0001). We used principal component analysis (PCA) to reduce various observed fungal species to fewer factors. Six groups (PCA factors) were obtained for dustborne fungi recovered from both floors and chairs. The models of the first PCA factors for both floors and chairs were similar to those for total fungal concentrations. The results of this study provide essential information to further evaluate the effects of dustborne fungi on office workers' health.
Insights
Indoor dust in offices harbors fungi, posing potential health risks to workers. Fungal levels on floors correlate with carbon dioxide and temperature, increasing over the year, while chair fungi vary seasonally and with floor dust.
Area of Science:
- Environmental Health
- Indoor Air Quality
- Mycology
Background:
- Fungi are widespread environmental microorganisms.
- Indoor dust is a significant reservoir for airborne fungi.
- The health impacts of indoor fungi on office workers are a growing concern.
Purpose of the Study:
- To characterize dustborne fungal populations in office environments.
- To investigate the relationship between fungal concentrations and environmental factors.
- To understand seasonal variations and correlations with dust loads.
Main Methods:
- Environmental sampling of culturable dustborne fungi from office floors and chairs.
- Measurement of surface dust levels, water activity, carbon dioxide, temperature, and relative humidity.
- Statistical analysis including regression and principal component analysis (PCA).
Main Results:
- Floor fungal concentrations were positively associated with carbon dioxide levels and moderate temperatures (20-22.5°C).
- Total fungal concentrations on floors increased throughout the year.
- Fungal populations on chairs showed significant seasonal variation, peaking in September and correlating with floor dust loads.
Conclusions:
- Office dust harbors diverse fungal communities influenced by environmental conditions.
- Understanding these fungal dynamics is crucial for assessing potential health risks to office workers.
- Further research is needed to link specific fungal exposures to health outcomes.