10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Air Quality in the Megacity of Beijing: From Sources to Control
MIN HU, Dongjie Shang, Yao Xiao, Jing Zheng, Song Guo, Zhijun Wu, Keding Lu, Limin Zeng, Sihua Lu, Shaodong Xie, Yuanhang Zhang, Peking University, Beijing, China
Abstract Number: 1068 Working Group: Air Quality in Megacities: from Sources to Control
Abstract Severe regional haze problem in the megacity of Beijing and surrounding areas has attracted much attention in recent years. It has the characteristics of rapid accumulation of PM2.5 pollution within 5 to 7 days duration, covering large areas. The presentation will give an overview on emissions reduction policies developed and implemented by the Chinese government. The Action Plan on Prevention and Control of Air Pollution (so called “Ten Major Measures” for air pollution) was conducted in 2013-2017. As the results the number of days of heavy air pollution (mainly occurred in winter) in Beijing was 58, 47, 46, 39, 23 days in 2013-2017, respectively, showing a decreasing feature year by year. The days of heavy pollution decreased by 35 days within five years, and the incidence of heavy pollution decreased significantly. PM2.5 also decreased significantly from 89.5 μg/m3 in 2013 to 58 μg/m3 in 2017. The spatial distribution of the whole Beijing area was still high in the south and low in the north, but the gap between the north and the south decreased.
The interplay between source emissions, atmospheric chemical mechanisms, meteorological conditions and aerosol thermodynamics is non-linear and quite complex. It is a great challenge to implement effective mitigation strategies. In order to obtain scientific understanding of haze pollution, we conducted intensive field campaigns, chamber simulation and modeling studies in Beijing and surrounding areas for years. Our results revealed that haze formation includes two processes: “seeds” production (efficient nucleation, primary emission) and rapid particle growth. During the pollution episodes secondary compounds (SNA, SOA) dominated in particle mass concentrations. The presentation will focus on source apportionments of PM2.5 and the mechanisms of chemical process during the haze formation in the wintertime of Beijing.