00Mechanism for the formation of the January 2013 heavy haze.pdf

SCIENCE CHINA Earth Sciences ? Science China Press and Springer-Verlag Berlin Heidelberg 2013 *Corresponding author (email: wys@) ?Corresponding author (email: lzr@) SPECIAL TOPIC: The Severe Fog and Haze Event over Eastern China in January 2013 January 2014 Vol.57 No.1: 14–25 ? RESEARCH PAPER ? doi: 10.1007/s11430-013-4773-4 Mechanism for the formation of the January 2013 heavy haze pollution episode over central and eastern China WANG YueSi*, YAO Li, WANG LiLi, LIU ZiRui?, JI DongSheng, TANG GuiQian, ZHANG JunKe, SUN Yang, HU Bo XIN JinYuan State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China Received August 12, 2013; accepted October 28, 2013; published online November 27, 2013 In January 2013, a long-lasting episode of severe haze occurred in central and eastern China, and it attracted attention from all sectors of society. The process and evolution of haze pollution episodes were observed by the “Forming Mechanism and Con- trol Strategies of Haze in China” group using an intensive aerosol and trace gases campaign that simultaneously obtained data at 11 ground-based observing sites in the CARE-China network. The characteristics and formation mechanism of haze pollu- tion episodes were discussed. Five haze pollution episodes were identified in the Beijing-Tianjin-Hebei (Jing-Jin-Ji) area; the two most severe episodes occurred during 9–15 January and 25–31 January. During these two haze pollution episodes, the maximum hourly PM2.5 mass concentrations in Beijing were 680 and 530 μg m ?3, respectively. The process and evolution of haze pollution episodes in other major cities in the Jing-Jin-Ji area, such as Shijiazhuang and Tianjin were almost the same as those observed in Beijing. The external cause of the severe haze episodes was the unusual atmospheric circulation, the depres- s