title: Severe haze episodes and seriously polluted fog water in Ji'nan, China.
abstract: Haze episodes often hit urban cities in China recently. Here, we present several continuous haze episodes with extremely high PM2.5 levels that occurred over several weeks in early 2013 and extended across most parts of the northern and eastern China-far exceeding the Beijing-Tianjin-Hebei region. Particularly, the haze episode covered ~1 million km(2) on January 14, 2013 and the daily averaged PM2.5 concentration exceeded 360 μg m(-3) in Ji'nan. The observed maximum hourly PM2.5 concentration in urban Ji'nan reached 701 μg m(-3) at 7:00 am (local time) in January 30. During these haze episodes, several fog events happened and the concurrent fog water was found to be seriously polluted. For the fog water collected in Ji'nan from 10:00 pm in January 14 to 11:00 am in January 15, sulfate, nitrate, and ammonium were the major ions with concentrations of 1.54 × 10(6), 8.98 × 10(5), and 1.75 × 10(6) μeq L(-1), respectively, leading to a low in-situ pH of 3.30. The sulfate content in the fog sample was more than 544 times as high as those observed in other areas. With examination of the simultaneously observed data on PM2.5 and its chemical composition, the fog played a role in scavenging and removing fine particles from the atmosphere during haze episodes and thus was seriously contaminated. However, the effect was not sufficient to obviously cleanse air pollution and block haze episodes.
authors.affiliation: Environment Research Institute, School of Environmental Science and Engineering, Shandong University, Ji'nan 250100, China.
authors.forename: Xinfeng
authors.initials: X
authors.lastname: Wang
authors.affiliation: Environment Research Institute, School of Environmental Science and Engineering, Shandong University, Ji'nan 250100, China; Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP(3)), Fudan Tyndall Centre, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, China. Electronic address: jmchen@sdu.edu.cn.
authors.forename: Jianmin
authors.initials: J
authors.lastname: Chen
authors.affiliation: Environment Research Institute, School of Environmental Science and Engineering, Shandong University, Ji'nan 250100, China.
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Sun
authors.affiliation: Environment Research Institute, School of Environmental Science and Engineering, Shandong University, Ji'nan 250100, China.
authors.forename: Weijun
authors.initials: W
authors.lastname: Li
authors.affiliation: Environment Research Institute, School of Environmental Science and Engineering, Shandong University, Ji'nan 250100, China.
authors.forename: Lingxiao
authors.initials: L
authors.lastname: Yang
authors.affiliation: Environment Research Institute, School of Environmental Science and Engineering, Shandong University, Ji'nan 250100, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Wen
authors.affiliation: Environment Research Institute, School of Environmental Science and Engineering, Shandong University, Ji'nan 250100, China. Electronic address: wxwang@sdu.edu.cn.
authors.forename: Wenxing
authors.initials: W
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
authors.forename: Xinming
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523, USA.
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Collett
authors.affiliation: Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP(3)), Fudan Tyndall Centre, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Shi
authors.affiliation: Environment Research Institute, School of Environmental Science and Engineering, Shandong University, Ji'nan 250100, China.
authors.forename: Qingzhu
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Environment Research Institute, School of Environmental Science and Engineering, Shandong University, Ji'nan 250100, China.
authors.forename: Jingtian
authors.initials: J
authors.lastname: Hu
authors.affiliation: Environment Research Institute, School of Environmental Science and Engineering, Shandong University, Ji'nan 250100, China.
authors.forename: Lan
authors.initials: L
authors.lastname: Yao
authors.affiliation: Environment Research Institute, School of Environmental Science and Engineering, Shandong University, Ji'nan 250100, China.
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Environment Research Institute, School of Environmental Science and Engineering, Shandong University, Ji'nan 250100, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Sui
authors.affiliation: Environment Research Institute, School of Environmental Science and Engineering, Shandong University, Ji'nan 250100, China.
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Sun
authors.affiliation: Environment Research Institute, School of Environmental Science and Engineering, Shandong University, Ji'nan 250100, China; Institut de Combustion, Aérothermique, Réactivité et Environnement, CNRS, 45071 Orléans cedex 02, France.
authors.forename: Abdelwahid
authors.initials: A
authors.lastname: Mellouki
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000706:statistics & numerical data; D001272:Atmosphere / Q000737:chemistry; D002681:China; D002947:Cities; D004784:Environmental Monitoring; D009589:Nitrogen Oxides / Q000032:analysis; D052638:Particulate Matter; D014887:Weather
chemical_list: D000393:Air Pollutants; D009589:Nitrogen Oxides; D052638:Particulate Matter
keywords: Carbonaceous materials; Eastern China; Fog; PM(2.5); Regional haze; Water-soluble ions