高校教室细菌气溶胶来源及其影响因素分析

Sources and Influence Factors of Bacterial Aerosol in University Classrooms

高校教室人员密度大和流动性强的特点会大幅度增加室内人员交叉感染疾病的风险。为探究高校教室室内细菌气溶胶来源特点及其影响因素,2018年12月至2019年12月,在正常教学活动期间,对北京某高校7间典型教室在关闭门窗且无机械通风条件下的室内和室外细菌气溶胶浓度、空气温度、相对湿度以及颗粒物浓度等参数进行了实测分析。结果表明:秋季室外细菌气溶胶平均浓度最高,春季和冬季次之,夏季最低;在室内长时间无人且关闭门窗的条件下,室内细菌气溶胶浓度主要受室外影响(R^2=0.72);有人工况较无人工况,教室内细菌气溶胶浓度增加了2.5倍,人员对室内细菌气溶胶的贡献显著;室外细菌气溶胶浓度与空气温度呈显著负相关(P<0.01),而与颗粒物浓度(PM1、PM2.5和PM10)呈显著正相关(P<0.01);室内细菌气溶胶浓度与室内空气相对湿度及PM10质量浓度呈显著正相关(P<0.05)。

The risk of cross-infection among indoor occupants will be greatly increased by the high occupant densities and mobility in university classrooms.In order to investigate the sources and influence factors of indoor bacterial aerosols in university classrooms,seven typical classrooms at a campus in Beijing were chosen for indoor and outdoor bacterial sampling during normal didactic activities from December 2018 to December 2019.The air temperature,relative humidity,and particulate concentrations near the sampling sites were concurrently measured under the condition of closed doors,windows and mechanical ventilation systems.The results show that outdoor bacterial average concentration was highest in autumn,followed by spring and winter,and lowest in summer.Under the condition of no occupant indoors for a long time and closed doors and windows,indoor bacterial concentrations were dominated by outdoors(R^2=0.72).With occupant presence,the bacterial concentrations increased by 2.5 times than unoccupied conditions,occupants have significant contribution to indoor bacterial aerosols.Outdoor bacterial concentrations have significant and negative correlation with air temperature(P<0.01),while having significant and positive correlations with particulate concentrations(PM1,PM2.5,and PM10)(P<0.01).Indoor bacterial concentrations have significant and positive correlations with relative humidity and PM10 mass concentrations(P<0.05).