空调列车通风系统卫生学评价

Hygienic Evaluation of Air Ventilation System in Air-Conditioned Carriages

[目的]调查空调列车通风系统污染状况,为开展疾病预防工作提供科学依据及合理建议。[方法]2011年4月至6月,选取空调列车具有代表性的3个车型(25G、25T和CRH-5),每个车型分硬座、硬卧、软卧、餐车4个监测点进行监测,监测送风系统的温度、湿度、可吸入颗粒物(PM10)、新风量、空气细菌总数、真菌总数、β-溶血性链球菌指标,同时监测风管内表面积尘量、积尘细菌总数、真菌总数指标和冷凝水嗜肺军团菌指标。[结果]25G型、25T型空调列车车顶式单元空调机组通风系统冷凝水中未检出嗜肺军团菌;3个车型(25G、25T和CRH-5)空调列车车顶式单元空调机组通风系统新风量分别为(49.1±10.3)、(41.5±18.1)、(52.4±12.3)m3(/h.人),送风中相对湿度分别为(40.1±1.5)%、(29.4±7.3)%、(42.1±4.5)%,细菌总数分别为(603.7±124.0)、(643.3±331.3)、(256.5±67.7)cfu/m3,真菌总数分别为(148.7±39.7)、(216.8±227.6)、0.0cfu/m3,β-溶血性链球菌分别为(7.3±5.6)、0.0、0.0cfu/m3;风管内表面积尘量分别为(8.5±1.5)、(9.2±8.7)、(5.0±0.5)g/m2。在监测结果中,相对湿度的差异有统计学意义(F=4.6856,P=0.0115),其余监测指标的差异无统计学意义。[结论]空调列车通风系统不同程度地存在管道积尘量和送风细菌总数、真菌总数、β-溶血性链球菌的问题,相关单位应定期及时地对空调列车通风系统进行清洗、消毒,有条件的单位可安装空气净化装置,以抑制微生物生长。

[Objective] To collect evidences of air ventilation system pollution of air-conditioned carriages and to provide scientific basis and reasonable proposals for disease prevention.[Methods] Three models of representative air-conditioned carriages（25G,25T and CRH-5） were selected,and each was monitored at 4 sampling points including hard seat,hard berth,soft berth and dining-car in April,May and June of 2011.The monitoring indices of air supply system included temperature,humidity,inhalable particles（PM10）,air exchange flow and the total colony forming units（CFU） of bacteria,fungi and β-type hemolytic streptococcus.The monitoring indices of air ventilation ducts included the amount of dust particles and the total CFU of bacteria and fungi.The monitoring index of condensed water was Legionella pneumophila.[Results] No Legionella pneumophila was found in the condensed water of air ventilation system of 25G and 25T carriages.The average air exchange flow of 25G,25T and CRH-5 carriages were（49.1±10.3）,（41.5±18.1） and（52.4±12.3） m3/（h·p） respectively.In the air supply system,the average humidity were（40.1±1.5）%,（29.4±7.3）% and（42.1±4.5）% respectively;the average CFU of bacteria were（603.7±124.0）,（643.3±331.3） and（256.5±67.7） cfu/m3 respectively;the average CFU of fungi were（148.7±39.7）,（216.8±227.6） and 0.0 cfu/m3 respectively;the average CFU of β-type hemolytic streptococcus were（7.3±5.6）,0.0 and 0.0 cfu/m3 respectively.In the air ventilation duct,the average amount of dust particles were（8.5±1.5）,（9.2±8.7） and（5.0±0.5） g/m2 respectively.There was a significant difference in humidity among selected models（F=4.685 6,P=0.011 5）,but no significant difference was found in other monitoring indices.[Conclusion] The problems of the amount of dust particles in air ventilation ducts and the total CFU of bacteria,fungi and β-type hemolytic streptococcus in air supply system of selected models exist in varying degrees.Regular cleaning and disinfection,and air purifier installment if allowed,should be undertaken to control microbes from growing in the air ventilation system of air-conditioned carriages.