Objective To investigate the hygienic status of central air conditioning systems in representative public places in a district of Shenzhen, so as to provide basis for hygienic regulation and management.
Methods The hygienic indices of 20 central air conditioning systems from representative public places (3 hospitals, 2 hotels and 1 office building) selected randomly were monitored according to the Specifcation for Hygiene Management Central Air Conditioning Ventilation System of Public Place.
Results The qualified rate of fresh air supplement was 40.0%. The qualified rates of PM10, total bacteria, total fungi and β-hemolytic streptococcus counts in supply air were 64.3%, 74.5%, 93.9% and 100%, respectively. The qualified rates of pipeline dust load, total bacteria, total fungi and β-hemolytic streptococcus on the surface of ventilation pipes were 63.1%, 100.0%, 91.7% and 100.0%, respectively. The qualified rate of Legionella pneumophilia was 91.9% in cooling water and condensed water.
Conclusion Certain degree of contamination existed in part of the central air conditioning systems in this district. Cleaning and disinfection should be conducted regularly, and the supervision on hygienic management should be strengthened.
DownLoad: