Contributions of Outdoor Fungi to Residential Exposures
Date Issued
2004
Date
2004
Author(s)
Luo, Wen-Chang
DOI
zh-TW
Abstract
By using the published temporal/seasonal and particle size distribution of outdoor airborne fungi data and meteorological information in the subtropical climate, we characterized the airborne fungal concentration indoor/outdoor/personal exposure relationships in a wind-induced naturally ventilated residence. We applied a size-dependent indoor/ outdoor ratio model coupled with a compartmental lung model based on a hygroscopic growth factor as a function of relative humidity on aerodynamic diameter of bioaerosol and concentration of fungal spores. We estimated that the maximum concentrations of indoor airborne fungi occurred in the size range of 0.65 - 2.5 μm. The average geometric mean diameters of airborne fungi decreased from outdoor 2.58 ± 0.37 to indoor 1.91 ± 0.12 μm in summer, whereas decreased from outdoor 2.79 ± 0.32 to indoor 1.73 ± 0.10 μm in winter. The higher indoor airborne fungal concentrations occurred in early morning and late afternoon in which median values were 699 and 626 CFU m-3 in summer as well as 138 and 99 CFU m-3 in winter, respectively, at 2 a.m. and 8 p.m. In the absence of indoor sources, summer has higher mean indoor/outdoor ratios of airborne fungal concentration (0.29 – 0.58) than that in winter (0.12 – 0.16). Lung region of extrathoracic (ET) has higher fungal concentration lung/indoor ratios (0.7 – 0.8) than that in bronchial (BB) (0.41 – 0.60), bronchiolar (bb) (0.12 – 0.40), and alveolar-interstitial (AI) (0.01 – 0.24) regions. The highest airborne fungal deposition dose (95th-percentile is 4600 CFU) occurred in 23:00 – 05:00 in summer in region AI with 95th-percentile fungal deposition rate of 0.22 CFU s-1.
Subjects
氣懸真菌
自然通風
溼度
吸濕
生物氣膠
沈降
Bioaerosol
Humidity
Airborne fungus
Deposition
Hygroscopic
Natural ventilation
Type
thesis
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