Rush-hour aromatic and chlorinated hydrocarbons in selected subway stations of Shanghai, China.
Air samples were collected simultaneously at platform, mezzanine and outdoor in five typical stations of subway system in Shanghai, China using stainless steel canisters and analyzed by gas chromatography-mass selective detector (GC-MSD) after cryogenic preconcentration. Benzene, toluene, ethylbenzene and xylenes (BTEX) at the platforms and mezzanines inside the stations averaged (10.3 +/- 2.1), (38.7 +/- 9.0), (19.4 +/- 10.1) and (30.0 +/- 11.1) microg/m3, respectively; while trichloroethylene (TrCE), tetrachloroethylene (TeCE) and para-dichlorobenzene (pDCB), vinyl chloride and carbon tetrachloride were the most abundant chlorinated hydrocarbons inside the stations with average levels of (3.6 +/- 1.3), (1.3 +/- 0.5), (4.1 +/- 1.1), (2.2 +/- 1.1) and (1.2 +/- 0.3) microg/m3, respectively. Mean levels of major aromatic and chlorinated hydrocarbons were higher indoor (platforms and mezzanines) than outdoor with average indoor/outdoor (I/O) ratios of 1.1-9.5, whereas no significant indoor/outdoor differences were found except for benzene and TrCE. The highly significant mutual correlations (p < 0.01) for BTEX between indoor and outdoor and their significant correlation (p < 0.05) with methyl tert-butyl ether (MTBE), a marker of traffic-related emission without other indoor and outdoor sources, indicated that BTEX were introduced into the subway stations from indoor/outdoor air exchange and traffic emission should be their dominant source. TrCE and pDCB were mainly from indoor emission and TeCE might have both indoor emission sources and contribution from outdoor air, especially in the mezzanines.
State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China. zhang_yl86@gig.ac.cn
Yanli
Y
Zhang
Chunlei
C
Li
Xinming
X
Wang
Hai
H
Guo
Yanli
Y
Feng
Jianmin
J
Chen
D000393:Air Pollutants / Q000032:analysis*; D001554:Benzene / Q000032:analysis; D001555:Benzene Derivatives / Q000032:analysis; D002681:China; D004784:Environmental Monitoring / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry; D006841:Hydrocarbons, Aromatic / Q000032:analysis*; D006843:Hydrocarbons, Chlorinated / Q000032:analysis*; D008738:Methyl Ethers / Q000032:analysis; D011890:Railroads; D014050:Toluene / Q000032:analysis; D014241:Trichloroethylene / Q000032:analysis; D014992:Xylenes / Q000032:analysis
D000393:Air Pollutants; D001555:Benzene Derivatives; D006841:Hydrocarbons, Aromatic; D006843:Hydrocarbons, Chlorinated; D008738:Methyl Ethers; D014992:Xylenes; D014241:Trichloroethylene; C043243:methyl tert-butyl ether; D014050:Toluene; D001554:Benzene; C004912:ethylbenzene