title: Characterization of aerosol optical properties, chemical composition and mixing states in the winter season in Shanghai, China.
abstract: Physical and chemical properties of ambient aerosols at the single particle level were studied in Shanghai from December 22 to 28, 2009. A Cavity-Ring-Down Aerosol Extinction Spectrometer (CRD-AES) and a nephelometer were deployed to measure aerosol light extinction and scattering properties, respectively. An Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) was used to detect single particle sizes and chemical composition. Seven particle types were detected. Air parcels arrived at the sampling site from the vicinity of Shanghai until mid-day of December 25, when they started to originate from North China. The aerosol extinction, scattering, and absorption coefficients all dropped sharply when this cold, clean air arrived. Aerosol particles changed from a highly aged type before this meteorological shift to a relatively fresh type afterwards. The aerosol optical properties were dependent on the wind direction. Aerosols with high extinction coefficient and scattering Ångström exponent (SAE) were observed when the wind blew from the west and northwest, indicating that they were predominantly fine particles. Nitrate and ammonium correlated most strongly with the change in aerosol optical properties. In the elemental carbon/organic carbon (ECOC) particle type, the diurnal trends of single scattering albedo (SSA) and elemental carbon (EC) signal intensity had a negative correlation. We also found a negative correlation (r=-0.87) between high mass-OC particle number fraction and the SSA in a relatively clean period, suggesting that particulate aromatic components might play an important role in light absorption in urban areas.
authors.affiliation: Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
authors.forename: Yuanlong
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Li
authors.affiliation: Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Chen
authors.affiliation: Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China; Fudan-Tyndall Center, Fudan University, Shanghai 200433, China.
authors.forename: Jianmin
authors.initials: J
authors.lastname: Chen
authors.affiliation: Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China; Fudan-Tyndall Center, Fudan University, Shanghai 200433, China. Electronic address: yangxin@fudan.edu.cn.
authors.forename: Xin
authors.initials: X
authors.lastname: Yang
authors.affiliation: Division of Math, Science and Technology, Nova Southeastern University, Fort Lauderdale, FL 33314, USA.
authors.forename: Song
authors.initials: S
authors.lastname: Gao
authors.affiliation: Department of Chemistry, Carleton College, Northfield, MN 55057, USA.
authors.forename: Deborah S
authors.initials: DS
authors.lastname: Gross
mesh_terms: D000336:Aerosols / Q000737:chemistry*; D000393:Air Pollutants / Q000737:chemistry*; D002681:China; D002947:Cities; D009391:Nephelometry and Turbidimetry; D010316:Particle Size; D012621:Seasons; D014887:Weather
chemical_list: D000336:Aerosols; D000393:Air Pollutants
keywords: ATOFMS; Aerosol optical properties; CRDS; Chemical composition