Objective To collect data on air pollution in Shanghai subway system for four months and to provide scientific basis and reasonable proposals for disease prevention and health supervision.
Methods Six representative metro stations of Shanghai subway system were selected.Each subway station was monitored with 4 sampling points on platform and concourse respectively.The monitoring was conducted three times a day for continuous 3 days in May,Jul,Nov of 2009 and Jan of 2010.The monitoring indices included respirable particulate matter (PM10),carbon dioxide (CO2),air exchange flow,hemolytic streptococcus and total colony forming units (CFU) of bacteria and fungi.
Results The average total count of bacteria in the ground stations in July was (30.1& #177;7.7) colony per plate,which was significantly higher than those in other selected months.The average total count of fungi in the ground stations in January was (9.4& #177;1.2) colony per plate,which was significantly lower than those in other selected months.The average concentration of PM10 in January was significantly higher than those in other selected months.The average total count of bacteria in the underground stations in May was (21.5& #177;4.1) colony per plate,which was significantly lower than those in other selected months.The average total count of fungi in the underground stations in May was (13.6& #177;1.6) colony per plate,which was significantly lower than those in other selected months,and it reached (37.1& #177;8.6) colony per plate in July,which was significantly higher than those in other selected months.The concentration of PM10 in January was significantly higher than those in other selected months.There was no significant seasonal difference for the concentration of CO2.Hemolytic streptococci was detected in only one sample of monitoring in November and the detection rate was 0.049%.
Conclusion The average concentration of PM10 in Shanghai subway system is higher in January than that in other months.Microbiological pollution in underground stations is more severe than that in ground stations.
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