Objective To investigate the hygienic management and pollution levels of central air conditioning systems (CACS) in selected public buildings and to provide basis to design related supervision strategies and promotion activities.
Methods Using stratified random sampling, 72 sets of CACS in 18 companies were selected. Hygienic management lots were obtained on-site. Survey forms were designed to collect information on cleaning, disinfection, testing, and management of CACS. A field investigation was conducted to evaluate hygienic indicators. Results were judged according to the Hygienic Specification for the Management of Central Ventilation and Air Conditioning System (DB 31/405-2012).
Results Of all the companies investigated, 33.33% companies presented required manuals on CACS design specifications, 22.22% delivered regular related trainings to their employees, 38.89% conducted regular hygiene tests, 5.55% conducted hygiene evaluations, and 11.11% cleaned or replaced vent filters regularly. The median of amount of dust on inner surface of exhaust pipe was 0.87 g/m2, the median of total number of bacteria was 2.0 cfu/cm2, and the total number of fungi was 4.0 cfu/cm2. The one-hour average concentration of carbon dioxide was 0.06%.
Conclusion A part of the CACSs in the public buildings pose hygienic threats by disqualified records management, equipment cleaning, and hygienic evaluations. It requires strengthened supervision and penalties.
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