Differentiating local and regional sources of Chinese urban air pollution based on effect of Spring Festival
Chuan Wang, Xiao-Feng Huang, Qiao Zhu, Li-Ming Cao, Bin Zhang, and Ling-Yan He
Key Laboratory for Urban Habitat Environmental Science and Technology, School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
Received: 25 Feb 2017 – Accepted for review: 27 Mar 2017 – Discussion started: 28 Mar 2017
Abstract. The emission of pollutants is extremely reduced during the annual Chinese Spring Festival (SF) in Shenzhen, China. During the SF, traffic flow drops by ~ 50 % and the industrial plants are almost entirely shut down in Shenzhen. To characterize the variation in ambient air pollutants due to the Spring Festival effect, various gaseous and particulate pollutants were measured in real time in urban Shenzhen over three consecutive winters (2014–2016). The results indicate that the concentrations of NOx, volatile organic compounds (VOCs), black carbon (BC), primary organic aerosols, chloride, and nitrate in submicron aerosols decrease by 50 %–80 % during the SF period relative to the non-Spring Festival periods, regardless of meteorological conditions, which suggests that these pollutants are mostly emitted or secondarily formed from urban local emissions. The concentration decreasing of regional pollutants or species emitted from natural sources, however, is found to be much less, especially for bulk PM2.5 (−24 %) and O3 (6 %). More detailed analysis of the Spring Festival effect reveals an urgent need to reduce emissions of SO2 and VOCs on a regional scale rather than on an urban scale to reduce urban PM2.5 in Shenzhen, which can also produce some use for reference for other megacities in China.
Wang, C., Huang, X.-F., Zhu, Q., Cao, L.-M., Zhang, B., and He, L.-Y.: Differentiating local and regional sources of Chinese urban air pollution based on effect of Spring Festival, Atmos. Chem. Phys. Discuss., doi:10.5194/acp-2017-173, in review, 2017.