Objective To evaluate the quality of cooling water in central air conditioning systems and its relationship with Legionella pneumophila contamination, and to provide scientific evidence for legionella disease prevention.
Methods A total of 36 public places in Nanshan District equipped with central air conditioning systems were recruited. Cooling water samples were collected and tested for physical, chemical, and microbiological indicators.
Results The water temperature of the cooling water was higher than average tap water, with a median of 30.0℃. The median of plate bacteria count was 6.8 CFU/mL, the median of turbidity was 3.5 NTU, and both were beyond the recommended limits for drinking water. The OR values (95%CI) of turbidity and total dissolved solids to Legionella pneumophila contamination in cooling water were 1.300 (1.011-1.672) and 1.102 (1.016-1.196) respectively.
Conclusion The turbidity and total dissolved solids of cooling water is a critical factor that may influence the growth and reproduction of Legionella pneumophila. Strengthening the management of cooling water is of great public health significance in preventing legionella disease.
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