PM2.5 pollution characteristics in the public areas of subway stations with different platform door systems
The characteristics of PM2.5 pollution were investigated for public areas of subway stations equipped with platform screen door(PSD)and platform bailout door(PBD)systems.Air samples were collected from both inside and outside selected subway stations,and the PM2.5 concentration and composition of the samples were determined.The positive matrix factorization(PMF)method was employed to determine the contributions of different sources to PM2.5 in the public areas.The mean PM2,5 concentration in the public areas of PSD stations was considerably lower than that of PBD stations but higher than the ambient PM2.5 concentration.The indoor-to-outdoor(I/O)ratios of elemental Fe and Cu in the PBD stations were 32and 9,respectively,surpassing those in the PSD stations(16 and 4).The source apportionment results were used to categorize the indoor and outdoor sources of PM25 in the public areas.The contribution of indoor sources to PM2.5 was 74％,with an elemental concentration of 40.1μg/m3,for PBD stations and 69％,with an elemental concentration of only 18.8μg/m3,for PSD stations.In both types of subway stations,indoor sources contributed over 80％of the heavy metal elements in the public areas.However,indoor sources produced a heavy metal concentration of 17.5μg/m3 in the PSD stations,which was 53％lower than that(36.9μg/m3)in the PBD stations.Therefore,installing a PSD system results in a considerably lower mass concentration and content of heavy metal elements of PM2.5 in public areas of subway stations than installing a PBD system.
subway stationPM2.5source apportionmentheavy metal
万方数据
