title: Persistent sulfate formation from London Fog to Chinese haze.
abstract: Sulfate aerosols exert profound impacts on human and ecosystem health, weather, and climate, but their formation mechanism remains uncertain. Atmospheric models consistently underpredict sulfate levels under diverse environmental conditions. From atmospheric measurements in two Chinese megacities and complementary laboratory experiments, we show that the aqueous oxidation of SO2by NO2is key to efficient sulfate formation but is only feasible under two atmospheric conditions: on fine aerosols with high relative humidity and NH3neutralization or under cloud conditions. Under polluted environments, this SO2oxidation process leads to large sulfate production rates and promotes formation of nitrate and organic matter on aqueous particles, exacerbating severe haze development. Effective haze mitigation is achievable by intervening in the sulfate formation process with enforced NH3and NO2control measures. In addition to explaining the polluted episodes currently occurring in China and during the 1952 London Fog, this sulfate production mechanism is widespread, and our results suggest a way to tackle this growing problem in China and much of the developing world.
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.|Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.|Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843.|Department of Chemistry, Texas A&M University, College Station, TX 77840.|School of Geographic Sciences, East China Normal University, Shanghai 200062, China.
authors.forename: Gehui
authors.initials: G
authors.lastname: Wang
authors.affiliation: Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843; renyi-zhang@tamu.edu mjmolina@ucsd.edu.|Department of Chemistry, Texas A&M University, College Station, TX 77840.|State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
authors.forename: Renyi
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843.|Department of Chemistry, Texas A&M University, College Station, TX 77840.|Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199.
authors.forename: Mario E
authors.initials: ME
authors.lastname: Gomez
authors.affiliation: Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843.|School of Environmental Science and Engineering, Shandong University, Jinan 250100, China.
authors.forename: Lingxiao
authors.initials: L
authors.lastname: Yang
authors.affiliation: Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843.
authors.forename: Misti
authors.initials: M
authors.lastname: Levy Zamora
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
authors.forename: Min
authors.initials: M
authors.lastname: Hu
authors.affiliation: Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843.
authors.forename: Yun
authors.initials: Y
authors.lastname: Lin
authors.affiliation: Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843.|State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
authors.forename: Jianfei
authors.initials: J
authors.lastname: Peng
authors.affiliation: Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843.|State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
authors.forename: Song
authors.initials: S
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.|Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.|University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Meng
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.|Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.
authors.forename: Jianjun
authors.initials: J
authors.lastname: Li
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.|Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.|University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Chunlei
authors.initials: C
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.|Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.
authors.forename: Tafeng
authors.initials: T
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.|Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.|University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yanqin
authors.initials: Y
authors.lastname: Ren
authors.affiliation: Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
authors.forename: Yuesi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Chinese Research Academy of Environmental Sciences, Beijing 100000, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.|Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.
authors.forename: Junji
authors.initials: J
authors.lastname: Cao
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.|Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.|Beijing Normal University, Beijing 100875, China.
authors.forename: Zhisheng
authors.initials: Z
authors.lastname: An
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.|Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.|Xi'an Jiaotong University, Xi'an 710049, China.
authors.forename: Weijian
authors.initials: W
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.|Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.
authors.forename: Guohui
authors.initials: G
authors.lastname: Li
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.|Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.|University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Jiayuan
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843.|Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China.
authors.forename: Pengfei
authors.initials: P
authors.lastname: Tian
authors.affiliation: Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843.|Department of Chemistry, Texas A&M University, College Station, TX 77840.
authors.forename: Wilmarie
authors.initials: W
authors.lastname: Marrero-Ortiz
authors.affiliation: Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843.|Department of Chemistry, Texas A&M University, College Station, TX 77840.
authors.forename: Jeremiah
authors.initials: J
authors.lastname: Secrest
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
authors.forename: Zhuofei
authors.initials: Z
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authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
authors.forename: Jing
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authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
authors.forename: Dongjie
authors.initials: D
authors.lastname: Shang
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
authors.forename: Limin
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authors.lastname: Zeng
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
authors.forename: Min
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authors.lastname: Shao
authors.affiliation: Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843.|State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.|Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Weigang
authors.initials: W
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.|Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.|University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yao
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authors.lastname: Huang
authors.affiliation: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91125.
authors.forename: Yuan
authors.initials: Y
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authors.affiliation: Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843.|Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China.
authors.forename: Yujiao
authors.initials: Y
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authors.affiliation: Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843.
authors.forename: Yixin
authors.initials: Y
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authors.affiliation: Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843.
authors.forename: Jiaxi
authors.initials: J
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authors.affiliation: Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843.
authors.forename: Bowen
authors.initials: B
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authors.affiliation: Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843.|School of Electrical Engineering, Wuhan University, Wuhan 430072, China.
authors.forename: Li
authors.initials: L
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authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.|Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.|University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yuting
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authors.affiliation: Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843.|School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China.
authors.forename: Yuemeng
authors.initials: Y
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authors.affiliation: Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843.|Beijing Normal University, Beijing 100875, China.
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authors.affiliation: Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843.|Program of Atmospheric Sciences, Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
authors.forename: Daniel
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authors.lastname: Rosenfeld
authors.affiliation: Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843.|School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, United Kingdom.
authors.forename: Peter S
authors.initials: PS
authors.lastname: Liss
authors.affiliation: Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843.
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authors.initials: RA
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authors.affiliation: Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843.|Aerodyne Research, Inc., Billerica, MA 01821-3976.
authors.forename: Charles E
authors.initials: CE
authors.lastname: Kolb
authors.affiliation: Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093 renyi-zhang@tamu.edu mjmolina@ucsd.edu.
authors.forename: Mario J
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mesh_terms: D000336:Aerosols / Q000032:analysis; D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000032:analysis; D002681:China; D002980:Climate; D004784:Environmental Monitoring / Q000379:methods; D006801:Humans; D008131:London; D009566:Nitrates; D009585:Nitrogen Dioxide / Q000009:adverse effects / Q000737:chemistry; D009589:Nitrogen Oxides / Q000032:analysis; D010316:Particle Size; D052638:Particulate Matter / Q000009:adverse effects / Q000032:analysis*; D013431:Sulfates / Q000009:adverse effects* / Q000032:analysis; D013461:Sulfur Oxides / Q000032:analysis; D014887:Weather
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D009566:Nitrates; D009589:Nitrogen Oxides; D052638:Particulate Matter; D013431:Sulfates; D013461:Sulfur Oxides; D009585:Nitrogen Dioxide
keywords: climate; human health; pollution; severe haze; sulfate aerosol