公共建筑冷却塔军团菌污染水平与环境因素现况调查

Investigation on legionella contamination and the environmental factors of cooling tower in public buildings

目的了解公共建筑集中空调冷却塔军团菌污染水平及周边环境因素现况。方法 2013年5-9月,选择北京市5类16户大中型公共建筑冷却塔作为调查对象;每月采集2-3次冷却水样品并进行嗜肺军团菌实验室检测,同时对冷却塔周边环境因素进行现场勘测与调查。结果采集冷却水样192件,嗜肺军团菌污染总体阳性率为34.4%;酒店、商场、办公楼、医院和地铁车站等几类场所冷却水嗜肺军团菌阳性率分别为34.1%、40.5%、13.3%、61.1%和100.0%;分析冷却塔周边环境因素发现68.8%冷却塔与敏感区的距离均〈7.5 m,66.7%医院、商场的冷却塔不仅紧邻敏感区,并且还位于敏感区上风向;并且93.8%的冷却塔均邻近医院、学校、人群密集的购物中心、办公楼及居住区等场所。结论公共建筑冷却塔军团菌污染情况较为严重;且冷却塔分布密度较高,与敏感区和易感人群聚集场所较为接近,应注意加强相关的防控措施。

Objective To investigate legionella contamination and the related environmental factors of cooling tower in public buildings of central air conditioning systems. Methods A total 16 public buildings in 5 types were visited from May to September in 2013. Water samples were collected from the cooling towers 2 - 3 time per month and sent to laboratory for legionella pneumophila testing. The information about the related environmental factors of cooling tower was collected by the questionnaires. Results Among 192 cooling tower water samples,overall positive rate of legionella pneumophila was 34. 4%.The positive rates of hotels,shopping malls,office buildings,hospitals and subway stations were 34. 1%,40. 5%,13. 3%,61. 1% and 100. 0%,respectively. There was significantly difference among different types of public buildings（ χ2= 22. 60,P〈0. 05）. 68. 8% cooling towers in this research were closed to sensitive area within 7. 5 meters. 66. 7% cooling towers of shopping mall and hospital were not only closed to sensitive area,but also located in the upwind direction. And 93. 8% cooling towers were closed to schools,hospitals,large crowd shopping malls,office buildings and residential areas. Conclusion The legionella contamination in cooling tower water of public buildings in Beijing is very serious. The distribution density of cooling towers were higher. The cooling towers were closed to sensitive area and susceptible population gathering places. The prevention and control measures of cooling tower should be further strengthened.