Legionella Pneumophila Contamination in Cooling Tower Water of Central Air Conditioning Systems in Public Places in Zhongshan

Objectives To investigate the contamination of legionella pneumophila in cooling tower water of central air conditioning systems and the hygienic status in public places in Zhongshan; and to provide scientific basis for controlling legionella contamination efficiently.

Methods Eighty two water samples were collected from cooling tower in 43 public places by random during June 2014 to November 2014 for the determination of legionella pneumophila, and the hygienic status was investigated by questionnaire.

Results Legionella pneumophila was detected in water samples from 8 of 43 public places. The detection rate(18.6%) of legionella pneumophila in cooling tower water was not significantly different among different types of public places, different service life of air conditioning systems, and different maintenance and disinfection status(P > 0.05). The detection rate of legionella pneumophila in water samples in regularly examined and non-regularly examined cooling tower water was 10.0% and 41.7%(P < 0.05), respectively.

Conclusions Contamination of legionella pneumophila in cooling tower water of central air conditioning systems has been detected in public places of Zhongshan. Supervision on the design and installation of cooling tower should be strengthened. The technique and procedure for cleaning cooling tower and water disinfection should be standardized. Comprehensive measures should be taken to reduce the danger of legionella pneumophila contamination.