Objective To understand the levels of carbon dioxide (CO2) and particulate matter (PM) in the carriages of metro trains in Shanghai.
Methods Levels of PM10 and CO2 were detected consecutively in two types of carriage with different passenger capacity. The PM less than 1.0, 2.0, 5.0 and 10.0 microns was measured respectively and their distribution was analyzed.
Results PM10 level declined smoothly as the metro in operation, and there was a significant difference between the data measured during door open-and-close and during regular operation (P<0.05). PM2.0 was the main component of inhalable particulates in metro train carriages, and accounted for 96% and 97% in small and large carriages respectively. CO2 concentration was increased dramatically in relatively large amplitude with the passenger volume increased, and was decreased slowly in small amplitude with the passenger volume decreased.
Conclusion The filter unit of central air conditioning system in metro lines has certain effect on air quality purification. Fresh air plays an important role in ensuring the indoor environment.
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