Control Effectiveness of Ultraviolet Germicidal Irradiation on Bioaerosols
Titel:
Control Effectiveness of Ultraviolet Germicidal Irradiation on Bioaerosols
Auteur:
Lin, Chia-Yu Li, Chih-Shan
Verschenen in:
Aerosol science and technology
Paginering:
Jaargang 36 (2002) nr. 4 pagina's 474-478
Jaar:
2002-01
Inhoud:
Because of increasing incidence of microorganism infections, there are concerns in engineering control of indoor microorganism for reducing airborne infectious diseases. Ultraviolet germicidal irradiation (UVGI) was considered to be promising to inactivate microorganisms. In this investigation, the influences of UV dosage, microorganism species, and relative humidity on UVGI effectiveness were evaluated in a laboratory test chamber. A Collison nebulizer generated aerosols containing Escherichia coli, Bacillus subtilis spores , cells of Candida famata var. flareri , and spores of Penicillium citrinum . The UVGI control effectiveness was determined as the ratio, N S / N 0 , where N S and N 0 were the colony concentrations collected by Andersen one-stage samplers at UVGI dosages of D and zero, respectively. In regard to 99% microorganism inactivation, the UVGI dosage ranges were 1017 to 2356 μW s/cm 2 , 15949 to 19345 μW s/cm 2 , 12917 to 17497 μW s/cm 2 , and 47984 to 89419 μW s/cm 2 for E. coli, B. subtilis , yeast, and P. citrinum , respectively. Significantly, the microorganism susceptibilities of E. coli were the highest and P. citrinum were the lowest. In regard to relative humidity effects, it was observed that the microorganism susceptibilities at 80% relative humidity were lower than those found at 50% relative humidity for all 4 types of the evaluated microorganisms.
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