Sanitary Quality Evaluation of Central Air Conditioning System in Public Area in Shenzhen Metro Line 7

Objectives To evaluate the sanitary quality of central air conditioning ventilation facilities in station halls and platforms of Shenzhen Metro Line 7.

Methods On the basis of the Hygienic standard for waiting room of public transit means (GB 9672-1996), the Hygienic specification of central air conditioning ventilation system in public buildings"(WS 394-2012), and the Code for design of metro (GB 50157-2013) requirements, field investigation, test, and evaluation of the sanitary quality of central air conditioning facilities and ventilation pipe in newly built Shenzhen Metro Line 7 were detected.

Results The investigation showed that some cooling towers were located on the upper wind side of the fresh air pavilion and were close to the cooling tower. Part of the new wind pavilion ground was not rigidified or greened. A small number of fresh air ducts had open-drainage channels and garbage was not cleaned up. Legionella pneumophila was not detected in cooling water or condensate water. The qualified rate of dust in the inner surface of the air duct was 100%, the total qualified rate of bacteria count was 95.69%, and the qualified rate of fungi count was 99.69%.

Conclusions The sanitary condition of central air conditioning was good in 23 stations, and the risk of Legionella pneumophila contamination existed in the fresh air outlets of 2 stations. In view of the problems found, suggestions for rectification are put forward.