Study of Airborne Ozone Applied to Indoor Disinfection

本研究主要在探討臭氧使用於室內空間之消毒效果的評估。評估的方法主要是使用生物氣膠進行氣相臭氧的消毒實驗，並且使用紫外光(UV)、MnO2觸媒進行分解臭氧尾氣的相關評估。生物氣膠的菌種選定大腸桿菌(Escherichia coli)、酵母菌(Candida famata var. flareri)、青黴菌(Penicillium citrinum)，及枯草桿菌(Bacillus subtilis)四種，生物氣膠系統以Collison Nebulizer製作生物氣膠及使用Andersen一階生物氣膠採樣器進行採樣。 消毒實驗的設計不採用將臭氧直接施放於空間中的方式，而是將室內空氣抽進一特別設計過的反應槽中，以進行各種條件的臭氧消毒評估。實驗的重點在於臭氧的劑量與消毒效果的關係，並進一步探討其他參數對消毒效果的影響。實驗的結果顯示，在0.33 ~ 1.0秒的接觸時間內，200 ppm的臭氧可使大腸桿菌的存活率降至0.05以下(殺菌率達95 %以上)，而同樣的臭氧濃度更可使酵母菌的存活率降到0.01以下，然而高達400 ppm的臭氧都無法使青黴菌孢子及枯草桿菌內孢子發生殺菌效果。 在使用紫外光分解臭氧尾氣的實驗結果中發現，當使用空氣進料臭氧機為臭氧的來源時，臭氧的分解率隨著與紫外光接觸時間增加而提高；以臭氧初始濃度為69.7 ~ 365 ppm為例，經過截面積為22.30 ~ 25.49 cm2及總長度為103 cm的紫外光照射，可達到約75 %的分解率。然而對於氧氣進料的臭氧機而言，紫外光幾乎無法對於臭氧有分解效果。而在觸媒MnO2分解臭氧的實驗結果，發現MnO2對氧氣進料的臭氧機所生產的臭氧可達90 %以上的分解率，但對於空氣進料的臭氧來源，其分解率則降到30 %以下。不過這部分的實驗仍有相當多的發展空間，造成差異的原因尚待更進一步的釐清。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.中文摘要.....................................................................................................I 英文摘要..................................................................................................III 目錄...........................................................................................................V 圖目錄......................................................................................................IX 表目錄...................................................................................................XIII 第一章 緒論..............................................................................................1 1.1研究緣起..........................................................................................1 1.2研究目的..........................................................................................2 1.3研究內容..........................................................................................2 第二章 文獻回顧......................................................................................5 2.1臭氧之相關介紹..............................................................................5 2.1.1臭氧之物化性質...................................................................5 2.1.2臭氧之相關化學反應...........................................................7 2.1.3空氣中臭氧對健康之影響.................................................13 2.1.4臭氧在大氣法規上的標準.................................................16 2.2臭氧之空間消毒............................................................................17 2.2.1室內空間之消毒殺菌.........................................................18 2.2.2氣相臭氧之殺菌效果.........................................................20 2.2.3影響臭氧殺菌的參數.........................................................24 2.2.4臭氧於空間消毒之應用.....................................................27 2.3生物氣膠簡介................................................................................31 2.3.1生物氣膠性質.....................................................................32 2.3.2生物氣膠之採樣.................................................................33 2.3.3生物氣膠實驗.....................................................................37 2.4分解氣相臭氧之方法....................................................................38 2.4.1氣相臭氧之自解.................................................................39 2.4.2紫外光分解氣相臭氧.........................................................40 2.4.3觸媒分解氣相臭氧.............................................................41 第三章 實驗方法與設備........................................................................43 3.1以生物氣膠進行氣相臭氧消毒實驗............................................43 3.1.1以生物氣膠進行氣相臭氧消毒實驗系統簡介.................43 3.1.2以生物氣膠進行氣相臭氧消毒實驗設備.........................45 3.1.3微生物實驗使用藥品與耗材.............................................47 3.1.4生物氣膠懸浮液之配製.....................................................49 3.1.5以生物氣膠進行氣相臭氧消毒實驗方法與步驟.............52 3.2以紫外光進行氣相臭氧分解實驗................................................55 3.2.1以紫外光進行氣相臭氧分解實驗系統簡介.....................55 3.2.2以紫外光進行氣相臭氧分解實驗器材.............................57 3.2.3以紫外光進行氣相臭氧分解實驗方法與步驟.................59 3.3以觸媒進行氣相臭氧分解實驗....................................................62 3.3.1以觸媒進行氣相臭氧分解實驗系統簡介.........................62 3.3.2以觸媒進行氣相臭氧分解實驗器材.................................62 3.3.3以觸媒進行氣相臭氧分解實驗方法與步驟.....................63 3.4氣相臭氧消毒系統實場試驗........................................................65 3.4.1實驗地點及設備簡介.........................................................65 3.4.2實驗方法與步驟.................................................................66 第四章 結果與討論................................................................................69 4.1以生物氣膠進行氣相臭氧消毒實驗結果....................................69 4.1.1生物氣膠產生系統穩定度試驗.........................................69 4.1.2臭氧濃度對殺菌效果的影響.............................................71 4.1.3接觸臭氧時間對殺菌效果的影響.....................................73 4.1.4不同菌種對臭氧耐受性的比較.........................................76 4.1.5菌液初始濃度對消毒效果的影響.....................................80 4.1.6以生物氣膠進行氣相臭氧消毒實驗所衍生的表面消毒效應.......................................................................................82 4.2以紫外光進行氣相臭氧分解實驗結果........................................89 4.2.1紫外光燈管光強度測定.....................................................89 4.2.2臭氧濃度對紫外光分解氣相臭氧之影響.........................91 4.2.3紫外光與臭氧接觸時間對臭氧分解率之影響.................93 4.2.4不同臭氧氣體來源對紫外光分解臭氧之影響.................97 4.3以觸媒進行氣相臭氧分解實驗結果..........................................100 4.4氣相臭氧消毒系統實場試驗結果..............................................106 第五章 結論與建議..............................................................................109 參考文獻................................................................................................113 附錄........................................................................................................12