A166-04
Uptake of Water-Soluble Gas-Phase Oxidation Products Drives Organic Particulate Pollution in Beijing
Monday, 14 December 2020: 17:42
Virtual
Georgios Gkatzelis1, Dimitrios K Papanastasiou2, Vlassis Karydis3, Thorsten Hohaus4, Ying Liu5, Sebastian H. Schmitt6, Patrick Schlag7, Hendrik Fuchs8, Anna Novelli4, Qi Chen9, Sebastian Broch4, Huabin Dong9, Frank Holland4, Zhaofeng Tan4, Xin Li10, Yuhan Liu9, Xuefei Ma9, David Reimer4, Franz Rohrer4, Domenico Taraborrelli11, Ralf Tillmann12, Haichao Wang9, Yusheng Wu9, Zhijun Wu9, Limin Zeng9, Min Hu9, Keding Lu9, Andreas Hofzumahaus4, Yuanhang Zhang9, Andreas Wahner4 and Astrid Kiendler-Scharr4, (1)Forschungszentrum Jülich GmbH, Jülich 52428, Germany, (2)Independent Researcher, Buffalo, NY, United States, (3)Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research, Jülich, Germany, (4)Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research, IEK-8: Troposphere, Jülich, Germany, (5)Peking University, College of Environmental Sciences and Engineering, Beijing, China, (6)TSI Incorporated, Aachen, Germany, (7)Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research, IEK-8: Troposphere, Jülich 52428, Germany, (8)Forschungszentrum Jülich, Institute of Energy and Climate Research, IEK-8: Troposphere, Jülich, Germany, (9)Peking University, State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Beijing, China, (10)Peking University, State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Beijing, China, (11)Forschungszentrum Jülich, Institute of Energy and Climate Research, IEK-8, Jülich, Germany, (12)Institute of Energy and Climate Research, IEK-8, Forschungszentrum Jülich, Jülich, Germany
Abstract:
Despite recent decreases in heavy haze pollution events in Chinese urban areas, the national and world health organization air quality standards are still exceeded. Observations from monitoring networks show a stronger decrease of aerosols directly emitted to the atmosphere relative to secondary organic aerosol (SOA) generated from oxidation processes. Here, a comprehensive set of online, state of the art analytical measurement techniques were used during wintertime 2016 near Beijing in order to measure the chemical composition and sources of particulate and gas-phase components.
During haze episodes SOA dominated the organic mass (55-80%) indicating active oxidation processes during winter conditions. Fast particle phase-state transition from semi-solid to liquid was triggered by the increase of aerosol liquid water content, and increased significantly the particle mass in pollution episodes. This transition resulted in the effective uptake of water-soluble gas phase compounds, and was sufficient to explain the increase in SOA mass. Photo-chemical characterization of the air mass showed that small gas-phase aldehydes and acids namely, formaldehyde, acetaldehyde, glycolaldehyde, formic and acetic acid, partitioned efficiently to the particle-phase and explained a significant fraction (15 to 25%) of the rapid increase in organic mass in the particle-phase.
The enhanced presence of aldehydes and acids during haze events can affect human health due to their carcinogenic nature. Future mitigation strategies to reduce non-methane volatile organic compound emissions, in particular, emissions related to industry and transportation, in order to effectively reduce organic particulate pollution in Beijing should be considered.
