Characteristics and sources of non-methane hydrocarbons and halocarbons in wintertime urban atmosphere of Shanghai, China
- 411 Downloads
The characteristics and sources of major hydrocarbons and halocarbons in the wintertime ambient air of urban center of Shanghai, a mega city of China, were investigated. Propane, toluene, ethyl acetate, and benzene were the most abundant hydrocarbons. The majority of species showed significant variability in mixing ratios with occasional episodic increases. The more common use of liquefied petroleum gas fuel for taxis and light motorcycles was believed to lead to high levels of ambient propane over the urban center of Shanghai. Correlating with toluene, dichloromethane, and 1,2-dichloroethane (1,2-DCE), abundant chloromethane (up to a daily mean of 1.61 ± 0.99 ppbv and a maximum of 5.34 ppbv) was mainly associated with industrial emissions, although biomass burnings exist widely in east China. The Chinese New Year (CNY) holiday period with no industrial activity over China provides a platform for the study of industrial emissions over the urban atmosphere of Shanghai. The normal weekly cycles were characterized by higher and more variable mixing ratios during weekdays which dropped during weekends. Enhanced mixing ratios were observed in the fortnight before the CNY holidays due to increased industrial emissions as a result of overtime production to make up for the holiday losses. During the CNY holidays, lower level and less variable mixing ratios were observed. A benzene/toluene (B/T) ratio of 0.6 ± 0.4 (mean ± std.) for the morning rush hour samples was identified to be the characteristic ratio of vehicular emissions. However, a B/T ratio of 0.4 ± 0.2 from vehicles and other sources was derived for the ambient air.
KeywordsNMHCs Halocarbon Mixing ratio Source Shanghai
This work is supported by the National Natural Science Foundation of China (NSFC, grant nos. 40705046, 40975078, and 40875075), Chinese Meteorological Administration (CMA, grant nos. FY-3YF 2006–056, and GYHY-QX 2007-6-19), Institute of Desert Meteorology/CMA (grant no. Sqj2005006), Guangdong Natural Science Foundation (grant no. 8251027501000002), and the Fundamental Research Funds for the Central Universities (grant no. 2010380003161542).
- Barletta, B., Meinardi, S., Simpson, I. J., Zou, S. C., Sherwood Rowland, F., & Blake, D. R. (2008). Ambient mixing ratios of nonmethane hydrocarbons (NMHCs) in two major urban centers of the Pearl River Delta (PRD) region: Guangzhou and Dongguan. Atmospheric Environment, 42, 4393–4408.CrossRefGoogle Scholar
- Barletta, B., Meinardi, S., Simpson, I. J., Atlas, E. L., Beyersdorf, A. J., Baker, A. K., et al. (2009). Characterization of volatile organic compounds (VOCs) in Asian and north American pollution plumes during INTEX-B: identification of specific Chinese air mass tracers. Atmospheric Chemistry and Physics, 9, 5371–5388.CrossRefGoogle Scholar
- Bayliss, D. L., Chen, C., Jarabek, A., Sonawane, B., & Valcovic, L. (1998). Carcinogenic effects of benzene: an update. Washington, DC: U.S, Environmental Protection Agency.Google Scholar
- Blake, N. J., Blake, D. R., Sive, B. C., Chen, T. Y., Rowland, F. S., Collins, J. E., Jr., et al. (1996). Biomass burning emissions and vertical distribution of atmospheric methyl halides and other reduced carbon gases in the South Atlantic region. Journal of Geophysical Research, 101, 24,151–24,164.Google Scholar
- Blake, N. J., Blake, D. R., Chen, T. Y., Collins, J. E., Jr., Sachse, G. W., Anderson, B. E., et al. (1997). Distribution and seasonality of selected hydrocarbons and halocarbons over the western Pacific basin during PEM-West A and PEM-West B. Journal of Geophysical Research, 102(D23), 28, 315–28, 328.CrossRefGoogle Scholar
- Blake, N. J., Blake, D. R., Simpson, I. J., Meinardi, S., Swanson, A. L., Lopez, J. P., et al. (2003). NMHCs and halocarbons in Asian continental outflow during the transport and chemical evolution over the Pacific (TRACE-P) Field Campaign: Comparison with PEM-West B. Journal of Geophysical Research, 108, 8806. doi: 10.1029/2002JD003367.CrossRefGoogle Scholar
- Chen, M. H., Li, D., & Chen, C. H. (2003). Survey and analysis on the status quo of fine particulates pollution in Shanghai. Shanghai Environmental Sciences, 22, 1038–1041.Google Scholar
- Clark, A. I., McIntyre, A. E., Perry, R., & Lester, J. N. (1984). Monitoring and assessment of ambient atmospheric concentrations of aromatic and halogenated hydrocarbons at urban, rural and motorway locations. Environmental Pollution Series B, Chemical and Physical, 7, 141–158.CrossRefGoogle Scholar
- de Gouw, J. A. (2004). Chemical composition of air masses transported from Asia to the US West Coast during ITCT 2K2: fossil fuel combustion versus biomass-burning signatures. Journal of Geophysical Research, 109. doi: 10.1029/2003JD004202.
- Gu, Y. G., Lu, S. L., Gu, J. Z., Chen, X. H., Fan, R., & Chen, Z. H. (2006). Analyses on time-space distributions and correlations of NO2, SO2 and PM10 in air in urban and suburb areas of Shanghai. Shanghai Environmental Sciences, 227, 201–205.Google Scholar
- McCulloch, A., Aucott, M. L., Benkovitz, C. M., Graedel, T. E., Kleiman, G., Midgley, P. M., et al. (1999). Global emissions of hydrogen chloride and chloromethane from coal combustion, incineration and industrial activities: reactive chlorine emissions inventory. Journal of Geophysical Research, 104, 8391–8403.CrossRefGoogle Scholar
- Schneider, M., Luxenhofer, O., Deissler, A., & Ballschmiter, K. (1998). C1–C15 alkyl nitrates, benzyl nitrate, and bifunctional nitrates: measurements in California and South Atlantic Air and global comparison using C2Cl4 and CHBr3 as marker molecules. Environmental Science and Technology, 32, 3055–3062.CrossRefGoogle Scholar
- Wang, T., Wong, C. H., Cheung, T. F., Blake, D. R., Arimoto, R., Baumann, K., et al. (2004). Relationships of trace gases and aerosols and the emission characteristics at Lin'an, a rural site in eastern China, during spring 2001. Journal of Geophysical Research, 109, D19S05. doi: 10.1029/2003JD004119.CrossRefGoogle Scholar
- WMO (World Meteorological Organization) (2007). Scientific Assessment of ozone depletion: 2006, Global Ozone Research and Monitoring Project-Report No. 50, 572 pp., Geneva, Switzerland.Google Scholar