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Surface Ocean and Lower Atmosphere Study—Air-Sea interactions and their climatic and environmental impacts
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The formation mechanism of atmospheric PM2.5 and haze pollution in the fall and winter of Beijing (Invited)
Wednesday 9th @ 0950-1010, Conference Room 7
Min HU* , State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University
Dongjie Shang, State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University
Yao Xiao, State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University
Xin Fang, State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University
Shiyi Chen, State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University
Keding Lu, State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University
Song Guo, State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University
Zhijun Wu, State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University
Limin Zeng, State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University
Yuanhang Zhang, State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University
Presenter Email: minhu@pku.edu.cn |
| Severe regional haze problem in the megacity Beijing and surrounding areas, caused by fast formation and growth of fine particles, has attracted much attention in recent years. After 5 years air pollution control primary emission decreased, while secondary pollution becomes prominent. 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 year by year 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 continuous improvement of air quality requires full understanding of formation mechanism of secondary air pollution, based on regional city clusters. The Intensive field campaigns were conducted in the fall and winter of 2017 in the north China Plain. Four pollution episodes were observed. The new particle formation and subsequent growth resulted in haze phenomenon. The formation mechanism of secondary components, such as nitrate, sulfate and SOA, was also discussed. The preliminary study has drawn the conclusions: SO2 and sulfate in PM decreased obviously due to coal burning control and using natural gas. Particulate nitrate became increasingly prominent due to daytime photochemistry. The liquid-phase particles, which provide efficient chemical reaction vessels, may facilitate the mass transfer of reactive gaseous precursors and subsequent multiphase reactions and further accelerate both secondary inorganic and organic aerosol formation. Mass loading of aerosols and their absorption and scattering coefficients would be enhanced after taking up water, thus amplifying the visibility degradation. |
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