Objective To sort and rank the hygienic conditions of the heating, ventilating, and air conditioning systems (HVACs) in Shanghai underground metro stations by grey correlation analysis, and to provide technical evidence for HVACs hygienic evaluation.
Methods A two-stage random sampling was carried out to select 6 underground stations of a metro line in shanghai. The subjective and objective indicators of HVACs' hygienic conditions in underground metro stations were comprehensively assessed. Moreover, the relationship between the subjective and objective indicators of selected HVACs' hygienic conditions was analyzed as well.
Results Among the 6 metro stations assessed by grey correlation analysis, 5 stations were graded as non-pollution and 1 as minor pollution. The levels of particulate matter less than 10 microns (PM10) in the HVACs were associated with the pollution conditions of filter, air supply outlet, return outlet, exhaust outlet, surrounding areas, as well as the quality of fresh air. Total bacterial counts had a certain relation with the quality of fresh air.
Conclusion Grey correlation analysis could be applied to comprehensive analysis on the pollution conditions in HVACs. The subjective indicators of hygienic evaluation are associated to the objective indicator set. Therefore, the hygienic condition of Shanghai metro HVACs can be improved by hierarchical management according to results of grey correlation analysis.
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