Study of Airborne Ozone Applied to Indoor Disinfection
Date Issued
2004
Date
2004
Author(s)
Ren, Li-Yu
DOI
zh-TW
Abstract
This main purpose of this study concerns the evaluation of the effect of applying gaseous ozone for indoor disinfection. Experiments were performed by mixing bioaerosols with airborne ozone in an enclosed flow-through system, while UV and catalytic converter MnO2 were used separately to decompose ozone in the exhaust air. Bioaerosols produced by the Collison Nebulizer were sampled by the Andersen one-stage Microbial Impactor. The microorganisms tested were: Escherichia coli, Candida famata var. flareri(yeast), Penicillium citrinum and Bacillus subtilis.
To investigate the bactericidal effects of ozone under multiple conditions, the contaminated air was pumped into a specially designed chamber to react with ozone, instead of releasing gaseous ozone directly into the indoor atmosphere and sampling all over. The goal of this research is to establish a dose-response relationship of ozone disinfection and find the influence of other variables. Results showed that under contact time for 0.33-1.0 sec, ozone concentration of 200 ppm could attain to a survival fraction of 0.05 for E. coli and 0.01 for Candida famata var. flareri. However, P. citrinum and B. subtilis spores showed no response to ozone concentrations even up to 400 ppm.
According to experiments conducted to decompose gaseous ozone with UV, the decomposition fraction of the residual ozone improves as the contact time increases in using an ozone generator with atmospheric air for the feeding gas. Ozone concentrations between 69.7 and 365 ppm attained a 75 % decomposition fraction while the mixture were forced through a 103 cm long tube with a cross section area of 22.30 to 25.49 cm2 and a UV lamp embedded. However, UV showed to be useless with the ozone generator fed by pure oxygen, only that using catalyst MnO2 could be quite efficient, instead.
Subjects
酵母菌
二氧化錳
臭氧
生物氣膠
枯草桿菌
空間消毒
大腸桿菌
青黴菌
紫外光
觸媒
Bioaerosol
MnO2
Yeast
UV
Catalyst
E.coli
Indoor disinfection
Ozone
P. citrinum.
B. subtilis
Type
thesis
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