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Typical Types and Formation Mechanisms of Haze in an Eastern Asia Megacity, ShanghaiAn intensive aerosol and gases campaign was performed at Shanghai in the Yangtze River Delta region over Eastern China from late March to early June 2009. This study provided a complementary picture of typical haze types and the formation mechanisms in megacities over China by using a synergy of ground-based monitoring, satellite and lidar observations. During the whole study period, several extreme low visibility periods were observed with distinct characteristics, and three typical haze types were identified, i.e. secondary inorganic pollution, dust, and biomass burning. Sulfate, nitrate and ammonium accounted for a major part of PM2.5 mass during the secondary inorganic pollution, and the good correlation between SO2/NOx/CO and PM2.5 indicated that coal burning and vehicle emission were the major sources. Large-scale regions with high AOD (aerosol optical depths) and low Angstrom exponent were detected by remote-sensing observation during the dust pollution episode, and this episode corresponded to coarse particles rich in mineral components such as Al and Ca contributing 76.8% to TSP. The relatively low Ca/Al ratio of 0.75 along with the air mass backward trajectory analysis suggested the dust source was from Gobi Desert. Typical tracers for biomass burning from satellite observation (column CO and HCHO) and from ground measurement (CO, particulate K+, OC, and EC) were greatly enhanced during the biomass burning pollution episode. The exclusive linear correlation between CO and PM2.5 corroborated that organic aerosol dominated aerosol chemistry during biomass burning, and the high concentration and enrichment degree of arsenic (As) could be also partly derived from biomass burning. Aerosol optical profile observed by lidar demonstrated that aerosol was mainly constrained below the boundary layer and comprised of spheric aerosol (depolarization ratio <5%) during the secondary inorganic and biomass burning episodes, while thick dust layer distributed at altitudes from near surface to 1.4 km (average depolarization ratio = 0.122+/-0.023) with dust accounting for 44-55% of the total aerosol extinction coefficient during the dust episode. This study portrayed a good picture of the typical haze types and proposed that identification of the complicated emission sources is important for the air quality improvement in megacities in China.
Document ID
20140010537
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
External Source(s)
doi:10.5194/acp-12-105-2012
Authors
Huang, K. (Fudan Univ. Shanghai, China)
Zhuang, G. (Fudan Univ. Shanghai, China)
Lin, Y. (Fudan Univ. Shanghai, China)
Fu, J. S. (Tennessee Univ. Knoxville, TN, United States)
Wang, Q. (Fudan Univ. Shanghai, China)
Liu, T. (Fudan Univ. Shanghai, China)
Zhang, R. (Fudan Univ. Shanghai, China)
Jiang, Y. (Fudan Univ. Shanghai, China)
Deng, C. (Fudan Univ. Shanghai, China)
Fu, Q. (Shanghai Environmental Monitoring Center Shanghai, China)
Hsu, N. C. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Cao, B. (Fudan Univ. Shanghai, China)
Date Acquired
August 8, 2014
Publication Date
January 2, 2012
Publication Information
Publication: Atmospheric Chemistry and Physics
Publisher: Copernicus Publications for EGU
Volume: 12
Issue: 1
Subject Category
Earth Resources And Remote Sensing
Report/Patent Number
GSFC-E-DAA-TN9373
Funding Number(s)
CONTRACT_GRANT: NSF 20877020
CONTRACT_GRANT: NSF 41128005
CONTRACT_GRANT: NSF20977017
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
haze
megacities
aerosols

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