Preliminary Analysis of Microbial Pollution Cause in Central Air Conditioning Ventilation System before Operation of Wuhan Subway Station

Objectives To analyze the pollution status of central air conditioning ventilation system before the operation of newly-built Wuhan subway station, and to explore its pollution causes.

Methods In 2016 and 2017, 30% of newly-built stations in Wuhan were randomly selected to carry out the hygienic monitoring of central air conditioning ventilation system.

Results A total of 116 samples were monitored by the central air conditioning ventilation system. The qualified rates of the total bacteria and fungi in the air supply outlet were 96.6% and 89.7%, respectively. The qualified rates of other indexes were 100.0%. The total fungi counts in the supply air in fan cabinet, hall layer and platform layer were statistically different(χ²=16.436, P < 0.05), but the total bacterial count in air supply was not statistically significant(χ²=1.078, P > 0.05).

Conclusions Before the operation of newly-built Wuhan new subway station, the bacterial contamination in the air supply system of central air conditioning came from the fan cabinet (and its front part), and the fungal contamination came from the fan cabinet (and its front part) and the air supply pipe.