Objective To estimate the levels of Legionella pneumophila pollution in cooling water of central air conditioning ventilation systems in public places in Taizhou City.
Methods According to the Health standards of the central air conditioning ventilation systems in public places (2006 edition), special surveys on Legionella pneumophila pollution in cooling water of central air conditioning ventilation systems in public places were conducted in August and September from 2009 to 2011.
Results A total of 22 public places were investigated, including 9 shopping malls (shops) and 13 hotels. Of the 41 cooling towers, the detection rate of Legionella pneumophila was 48.78% (20/41). The detection rates were 62.50% (10/16), 15.39% (2/13), and 66.67% (8/12), respectively, for 2009, 2010, and 2011, and were 13.33% (2/15) and 69.23% (18/26) respectively for the malls (shops) and the hotels. The detection rate of Legionella pneumophila in the 127 cooling water samples was 43.31% (55/127), 60.00% (24/40), 15.56% (7/45), and 57.14% (24/42) respectively for the consecutive three years, and 19.51% (8/41) and 54.65% (47/86) respectively for the malls (shops) and the hotels.
Conclusion The cooling water of central air conditioning ventilation systems in public places is seriously polluted with Legionella pneumophila, and may pose potential threats to those who have worked in this environment for a long-term period. Therefore, the prevention and control of Legionella pneumophila pollution in cooling water of central air conditioning ventilation systems in public places should be strengthened by regular cleaning and disinfection.
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