Chen Nai-Tzu, Su Yu-Min, Hsu Nai-Yun, Wu Pei-Chih, Su Huey-Jen
Department of Environmental and Occupational Health, College of Medicine, National Cheng Kung University, 138 Sheng-Li Road, Tainan 70403, Taiwan.
J Environ Monit. 2012 Oct 26;14(10):2692-7. doi: 10.1039/c2em30113j. Epub 2012 Aug 21.
A three-week-long biological sampling scheme was conducted in two child daycare centers (CDCCs) in order to investigate interdiurnal and diurnal variations in indoor airborne microbes as well as the efficiency of weak acid hypochlorous water (WAHW) on disinfecting indoor microbes. During the second week of sampling, WAHW was sprayed using a fogger in the classroom after children had left and before they returned the next morning. An identical cycle of experiments was performed twice in the winter and spring. Without WAHW intervention, the respective mean of the indoor concentrations and I/O ratios were 8732-47581 CFU m(-3) and 0.96-2.53 for fungi, and 6706-28998 CFU m(-3) and 1.10-11.92 for bacteria, showing severe bio-contamination in the CDCCs. Moreover, a relatively high level of bacterial pollution was found at noon, whereas a greater fungal pollution could be detected in the morning and at noon. Among five school days, the fungal and bacterial pollution may be higher on Monday and on Wednesday, Thursday, and Friday, respectively. Furthermore, with WAHW intervention, the indoor microbial concentrations and I/O ratios were decreased significantly. The reduction of I/O ratios caused by WAHW disinfection was accomplished in the morning for bacteria and in the morning, at noon, and in the afternoon for fungi. In conclusion, this study clearly clarified the risky period during which children may be exposed to hazardous environments, and demonstrated the effectiveness of spraying WAHW the night before on decontaminating indoor airborne microbes on the following day, especially in the case of fungi.
为了调查室内空气微生物的日间和昼夜变化以及弱酸性次氯酸水（WAHW）对室内微生物的消毒效果，在两个儿童日托中心（CDCC）开展了为期三周的生物采样计划。在采样的第二周，儿童离开教室后、次日早晨返回之前，使用喷雾器在教室内喷洒WAHW。在冬季和春季重复进行了两轮相同的实验。在没有WAHW干预的情况下，真菌的室内浓度和I/O比的各自平均值分别为8732 - 47581 CFU m(-3)和0.96 - 2.53，细菌的室内浓度和I/O比的各自平均值分别为6706 - 28998 CFU m(-3)和1.10 - 11.92，表明CDCCs存在严重的生物污染。此外，中午发现细菌污染水平相对较高，而在早晨和中午可检测到更高的真菌污染。在五个上学日中，真菌和细菌污染可能分别在周一以及周三、周四和周五更高。此外，通过WAHW干预，室内微生物浓度和I/O比显著降低。WAHW消毒导致的I/O比降低在上午对细菌而言得以实现，对真菌而言则在上午、中午和下午得以实现。总之，本研究明确了儿童可能暴露于危险环境的风险期，并证明了前一晚喷洒WAHW对次日室内空气传播微生物的去污效果，尤其是对真菌的去污效果。
