Department of Environmental Resource Management, Chia-Nan University of Pharmacy and Science, Tainan 71710, Taiwan, Republic of China.
J Air Waste Manag Assoc. 2013 Jul;63(7):796-805. doi: 10.1080/10962247.2012.735212.
In Taiwan, the food and drink requirements of students and faculty members are met by student cafeterias. The air quality within these cafeterias should satisfy the guidelines laid down by the Taiwan Environmental Protection Agency (Taiwan EPA). Accordingly, this study performed an experimental investigation into the efficiency of two different gaseous chlorine dioxide (ClO2) treatments in disinfecting a local student cafeteria, namely a single, one-off application and a twice-daily application. In both cases, the ClO2 was applied using strategically placed aerosol devices. The air quality before and after disinfection was evaluated by measuring the bioaerosol levels of bacteria and fungi. Moreover, a stepwise discriminant analysis method was applied for predicting the residual concentrations of bacteria and fungi, as a function of the environmental parameters and the ClO2 concentration. The experimental results showed that the average background levels of bacteria and fungi prior to ClO2 disinfection were 972.5 +/- 623.6 and 1534.1 +/- 631.8 colony-forming units (CFU)/m3, respectively. A single ClO2 application was found to reduce the bacterial and fungal concentration levels by as much as 65% and 30%, respectively. By contrast, a twice-daily ClO2 application was found to reduce the bacterial and fungal concentration levels by as much as 74% and 38%, respectively. The statistical analysis results showed that the residual bacterial concentration level was determined primarily by the number of individuals present in the cafeteria, the temperature, and the ClO2 concentration, whereas the residual fungal concentration level was determined mainly by the temperature, the total number of suspended particles, and the ClO2 concentration. Thus, the integrated results suggest that the air quality guidelines prescribed by the Taiwan EPA for student cafeteria can best be achieved by applying ClO2 twice daily using an appropriate deployment of aerosol devices.
ClO2 gas can destroy all manner of microorganisms, including bacteria, spores, fungi, viruses, and even protozoans, in indoor environments. Moreover, it is popularly known that bioaerosols are able to grow and propagate on a wide variety of building materials and indoor surfaces. Thus, through optimal ClO2 disinfection methodology, the indoor microbial contaminants can be decreased and the residual concentrations of bacteria and fungi as a function of the environmental parameters and the ClO2 concentration can be predicted via some statistical techniques.
在台湾，学生和教师的饮食需求由学生食堂满足。这些食堂内的空气质量应符合台湾环境保护署（台湾 EPA）规定的准则。因此，本研究对当地学生食堂使用两种不同气态二氧化氯（ClO2）处理方法的效率进行了实验研究，即单次一次性应用和每日两次应用。在这两种情况下，ClO2 都使用策略性放置的气溶胶设备进行应用。通过测量细菌和真菌的生物气溶胶水平来评估消毒前后的空气质量。此外，应用逐步判别分析方法来预测细菌和真菌的残留浓度，作为环境参数和 ClO2 浓度的函数。实验结果表明，在 ClO2 消毒之前，细菌和真菌的平均背景水平分别为 972.5±623.6 和 1534.1±631.8 菌落形成单位（CFU）/m3。单次 ClO2 应用可使细菌和真菌浓度分别降低多达 65%和 30%。相比之下，每日两次 ClO2 应用可使细菌和真菌浓度分别降低多达 74%和 38%。统计分析结果表明，残留细菌浓度水平主要由食堂内的人数、温度和 ClO2 浓度决定，而残留真菌浓度水平主要由温度、总悬浮颗粒物数和 ClO2 浓度决定。因此，综合结果表明，通过使用适当的气溶胶设备每天两次应用 ClO2，可以最好地实现台湾 EPA 为学生食堂规定的空气质量标准。
ClO2 气体可以在室内环境中破坏各种微生物，包括细菌、孢子、真菌、病毒，甚至原生动物。此外，众所周知，生物气溶胶能够在各种建筑材料和室内表面上生长和繁殖。因此，通过优化 ClO2 消毒方法，可以减少室内微生物污染物，并且可以通过一些统计技术预测细菌和真菌的残留浓度作为环境参数和 ClO2 浓度的函数。
