Articles | Volume 24, issue 13 
            
                
                    
            
            
            https://doi.org/10.5194/acp-24-7687-2024
                    © Author(s) 2024. This work is distributed under 
the Creative Commons Attribution 4.0 License.
                the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/acp-24-7687-2024
                    © Author(s) 2024. This work is distributed under 
the Creative Commons Attribution 4.0 License.
                the Creative Commons Attribution 4.0 License.
Measurement report: Size-resolved secondary organic aerosol formation modulated by aerosol water uptake in wintertime haze
Jing Duan
                                            State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
                                        
                                    Ru-Jin Huang
CORRESPONDING AUTHOR
                                            
                                    
                                            State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
                                        
                                    
                                            University of Chinese Academy of Sciences, Beijing 100049, China
                                        
                                    Ying Wang
                                            State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
                                        
                                    
                                            Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China
                                        
                                    Haobin Zhong
                                            School of Advanced Materials Engineering, Jiaxing Nanhu University, Jiaxing  314001, China
                                        
                                    Chunshui Lin
                                            State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
                                        
                                    Wei Huang
                                            State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
                                        
                                    Yifang Gu
                                            State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
                                        
                                    Jurgita Ovadnevaite
                                            School of Physics and Centre for Climate and Air Pollution Studies, Ryan Institute, University of Galway, University Road, Galway, H91CF50, Ireland
                                        
                                    Darius Ceburnis
                                            School of Physics and Centre for Climate and Air Pollution Studies, Ryan Institute, University of Galway, University Road, Galway, H91CF50, Ireland
                                        
                                    Colin O'Dowd
                                            School of Physics and Centre for Climate and Air Pollution Studies, Ryan Institute, University of Galway, University Road, Galway, H91CF50, Ireland
                                        
                                    Related authors
Chunshui Lin, Ru-Jin Huang, Jing Duan, Jing Qu, Jiahua Liu, Yi Liu, Yan Luo, Wei Huang, Wei Xu, Yanan Zhan, Zhitao Liu, Sihan Liu, Qingshuang Zhang, Quan Liu, Zirui Liu, Shengrong Lou, Huinan Yang, Dan Dan Huang, Cheng Huang, and Hongli Wang
                                        EGUsphere, https://doi.org/10.5194/egusphere-2025-2521, https://doi.org/10.5194/egusphere-2025-2521, 2025
                                    Short summary
                                    Short summary
                                            
                                                Since China's 2013 Clean Air Act cut PM2.5 by over half, winter haze in the North China Plain persists due to secondary organic aerosols now dominating primary pollutants, requiring urgent regional cooperation to address model-underestimated chemical transformations and cross-border pollution.
                                            
                                            
                                        Shuzheng Guo, Chunxiang Ye, Weili Lin, Yi Chen, Limin Zeng, Xuena Yu, Jinhui Cui, Chong Zhang, Jing Duan, Haobin Zhong, Rujin Huang, Xuguang Chi, Wei Nie, and Aijun Ding
                                        EGUsphere, https://doi.org/10.5194/egusphere-2024-262, https://doi.org/10.5194/egusphere-2024-262, 2024
                                    Preprint archived 
                                    Short summary
                                    Short summary
                                            
                                                @Tibet field campaigns 2021 discovered surprisingly high levels and activity contributions of oxygenated volatile organic compounds on the southeast of the Tibetan Plateau, which suggests that OVOCs may play a larger role in the chemical reactions that occur in high-altitude regions than previously thought.
                                            
                                            
                                        Yifang Gu, Ru-Jin Huang, Jing Duan, Wei Xu, Chunshui Lin, Haobin Zhong, Ying Wang, Haiyan Ni, Quan Liu, Ruiguang Xu, Litao Wang, and Yong Jie Li
                                    Atmos. Chem. Phys., 23, 5419–5433, https://doi.org/10.5194/acp-23-5419-2023, https://doi.org/10.5194/acp-23-5419-2023, 2023
                                    Short summary
                                    Short summary
                                            
                                                Secondary organic aerosol (SOA) can be produced by various pathways, but its formation mechanisms are unclear. Observations were conducted in the North China Plain during a highly oxidizing atmosphere in summer. We found that fast photochemistry dominated SOA formation during daytime. Two types of aqueous-phase chemistry (nocturnal and daytime processing) take place at high relative humidity. The potential transformation from primary organic aerosol (POA) to SOA was also an important pathway.
                                            
                                            
                                        Chunshui Lin, Ru-Jin Huang, Haobin Zhong, Jing Duan, Zixi Wang, Wei Huang, and Wei Xu
                                    Atmos. Chem. Phys., 23, 3595–3607, https://doi.org/10.5194/acp-23-3595-2023, https://doi.org/10.5194/acp-23-3595-2023, 2023
                                    Short summary
                                    Short summary
                                            
                                                The complex interaction between O3 and PM2.5, coupled with the topology of the Fenwei Plain and the evolution of the boundary layer height, highlights the challenges in further reducing particulate pollution in winter despite years of efforts to reduce emissions. Through scenario analysis in a chemical box model constrained by observation, we show the co-benefits of reducing NOx and VOCs simultaneously in reducing ozone and SOA.
                                            
                                            
                                        Jing Duan, Ru-Jin Huang, Yifang Gu, Chunshui Lin, Haobin Zhong, Wei Xu, Quan Liu, Yan You, Jurgita Ovadnevaite, Darius Ceburnis, Thorsten Hoffmann, and Colin O'Dowd
                                    Atmos. Chem. Phys., 22, 10139–10153, https://doi.org/10.5194/acp-22-10139-2022, https://doi.org/10.5194/acp-22-10139-2022, 2022
                                    Short summary
                                    Short summary
                                            
                                                Biomass-burning-influenced oxygenated organic aerosol (OOA-BB), formed from the photochemical oxidation and aging of biomass burning OA (BBOA), was resolved in urban Xi’an. The aqueous-phase processed oxygenated OA (aq-OOA) concentration was more dependent on secondary inorganic aerosol (SIA) content and aerosol liquid water content (ALWC). The increased aq-OOA contribution during SIA-enhanced periods likely reflects OA evolution due to the addition of alcohol or peroxide groups
                                            
                                            
                                        Haobin Zhong, Ru-Jin Huang, Chunshui Lin, Wei Xu, Jing Duan, Yifang Gu, Wei Huang, Haiyan Ni, Chongshu Zhu, Yan You, Yunfei Wu, Renjian Zhang, Jurgita Ovadnevaite, Darius Ceburnis, and Colin D. O'Dowd
                                    Atmos. Chem. Phys., 22, 9513–9524, https://doi.org/10.5194/acp-22-9513-2022, https://doi.org/10.5194/acp-22-9513-2022, 2022
                                    Short summary
                                    Short summary
                                            
                                                To investigate the physico-chemical properties of aerosol transported from major pollution regions in China, observations were conducted ~200 m above the ground at the junction location of the two key pollution areas. We found that the formation efficiency, oxidation state and production rate of secondary aerosol were different in the transport sectors from different pollution regions, and they were largely enhanced by the regional long-distance transport.
                                            
                                            
                                        Yandong Tong, Veronika Pospisilova, Lu Qi, Jing Duan, Yifang Gu, Varun Kumar, Pragati Rai, Giulia Stefenelli, Liwei Wang, Ying Wang, Haobin Zhong, Urs Baltensperger, Junji Cao, Ru-Jin Huang, André S. H. Prévôt, and Jay G. Slowik
                                    Atmos. Chem. Phys., 21, 9859–9886, https://doi.org/10.5194/acp-21-9859-2021, https://doi.org/10.5194/acp-21-9859-2021, 2021
                                    Short summary
                                    Short summary
                                            
                                                We investigate SOA sources and formation processes by a field deployment of the EESI-TOF-MS and L-TOF AMS in Beijing in late autumn and early winter. Our study shows that the sources and processes giving rise to haze events in Beijing are variable and seasonally dependent: (1) in the heating season, SOA formation is driven by oxidation of aromatics from solid fuel combustion; and (2) under high-NOx and RH conditions, aqueous-phase chemistry can be a major contributor to SOA formation.
                                            
                                            
                                        Wei Yuan, Ru-Jin Huang, Lu Yang, Ting Wang, Jing Duan, Jie Guo, Haiyan Ni, Yang Chen, Qi Chen, Yongjie Li, Ulrike Dusek, Colin O'Dowd, and Thorsten Hoffmann
                                    Atmos. Chem. Phys., 21, 3685–3697, https://doi.org/10.5194/acp-21-3685-2021, https://doi.org/10.5194/acp-21-3685-2021, 2021
                                    Short summary
                                    Short summary
                                            
                                                We characterized the seasonal variations in nitrated aromatic compounds (NACs) in composition, sources, and their light absorption contribution to brown carbon (BrC) aerosol in Xi'an, Northwest China. Our results show that secondary formation and vehicular emission were dominant sources in summer (~80 %), and biomass burning and coal combustion were major sources in winter (~75 %), and they indicate that the composition and sources of NACs have a profound impact on the light absorption of BrC
                                            
                                            
                                        Baihua Chen, Lu Lei, Emmanuel Chevassus, Wei Xu, Ling Zhen, Haobin Zhong, Lin Wang, Chunshui Lin, Ru-Jin Huang, Darius Ceburnis, Colin O'Dowd, and Jurgita Ovadnevaite
                                    Atmos. Chem. Phys., 25, 14205–14219, https://doi.org/10.5194/acp-25-14205-2025, https://doi.org/10.5194/acp-25-14205-2025, 2025
                                    Short summary
                                    Short summary
                                            
                                                This study uses machine learning to separate marine primary organic aerosol (POA) and secondary organic aerosol (SOA) from 1 decade of high-resolution data. POA averages 51 % of marine organic aerosols annually, peaking at 63 % in summer. A support vector regression model, validated via fuzzy clustering and Monte Carlo simulations, identifies seasonal patterns of POA linked to biological activity. We found diverse impacts of marine POA and SOA on the aerosol hygroscopicity and mixing state.
                                            
                                            
                                        Nikhil Korhale, Tabish Ansari, Tim Butler, Jurgita Ovadndevaite, Colin D. O'Dowd, and Liz Coleman
                                        EGUsphere, https://doi.org/10.5194/egusphere-2025-3824, https://doi.org/10.5194/egusphere-2025-3824, 2025
                                    This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP). 
                                    Short summary
                                    Short summary
                                            
                                                We investigate the distribution and trends of surface ozone and its precursors over Ireland using advanced modelling to determine the drivers of ozone. Trajectory analysis is used to trace the origins of air masses, revealing the impact of transboundary pollution and atmospheric transport. The rising trend has been observed at urban sites over the past two decades, but without a similar trend at coastal sites. Coastal areas consistently show higher ozone levels than rural and urban areas.
                                            
                                            
                                        Yujue Wang, Yizhe Yi, Wei Xu, Yiwen Zhang, Shubin Li, Hong-Hai Zhang, Mingliang Gu, Shibo Yan, Jialei Zhu, Chao Zhang, Jinhui Shi, Yang Gao, Xiaohong Yao, and Huiwang Gao
                                        EGUsphere, https://doi.org/10.5194/egusphere-2025-3951, https://doi.org/10.5194/egusphere-2025-3951, 2025
                                    Short summary
                                    Short summary
                                            
                                                Marine organic aerosols remain poorly quantified, which limits our understanding on the climate regulation of marine aerosols. Based on shipboard cruises over the Pacific Ocean, we proposed an observation-based parameterization approach to estimate the primary and secondary marine organic aerosols using sea surface chlorophyll a and sea salts in marine aerosols. The results highlight that the spatial distribution of marine organic aerosols was driven by the marine biological activities.
                                            
                                            
                                        Chunshui Lin, Ru-Jin Huang, Jing Duan, Jing Qu, Jiahua Liu, Yi Liu, Yan Luo, Wei Huang, Wei Xu, Yanan Zhan, Zhitao Liu, Sihan Liu, Qingshuang Zhang, Quan Liu, Zirui Liu, Shengrong Lou, Huinan Yang, Dan Dan Huang, Cheng Huang, and Hongli Wang
                                        EGUsphere, https://doi.org/10.5194/egusphere-2025-2521, https://doi.org/10.5194/egusphere-2025-2521, 2025
                                    Short summary
                                    Short summary
                                            
                                                Since China's 2013 Clean Air Act cut PM2.5 by over half, winter haze in the North China Plain persists due to secondary organic aerosols now dominating primary pollutants, requiring urgent regional cooperation to address model-underestimated chemical transformations and cross-border pollution.
                                            
                                            
                                        Jingye Ren, Wei Xu, Ru-Jin Huang, Fang Zhang, Ying Wang, Lu Chen, Jurgita Ovadnevaite, Darius Ceburnis, and Colin O’Dowd
                                        EGUsphere, https://doi.org/10.5194/egusphere-2025-3284, https://doi.org/10.5194/egusphere-2025-3284, 2025
                                    Short summary
                                    Short summary
                                            
                                                Impact of mixing state on cloud condensation nuclei (CCN) activity was incorporated in very limited modeling with typically simplified assumption. This study derived a mixing state index from hygroscopicity and systematically investigated its impacts on CCN activity in inland and coastal air. An entropy-based parameterization proposed here offers a novel approach to reduce model complexity in representing aerosol CCN activation, enabling more accurate simulations of aerosol CCN capacity.
                                            
                                            
                                        Aino Ovaska, Elio Rauth, Daniel Holmberg, Paulo Artaxo, John Backman, Benjamin Bergmans, Don Collins, Marco Aurélio Franco, Shahzad Gani, Roy M. Harrison, Rakes K. Hooda, Tareq Hussein, Antti-Pekka Hyvärinen, Kerneels Jaars, Adam Kristensson, Markku Kulmala, Lauri Laakso, Ari Laaksonen, Nikolaos Mihalopoulos, Colin O'Dowd, Jakub Ondracek, Tuukka Petäjä, Kristina Plauškaitė, Mira Pöhlker, Ximeng Qi, Peter Tunved, Ville Vakkari, Alfred Wiedensohler, Kai Puolamäki, Tuomo Nieminen, Veli-Matti Kerminen, Victoria A. Sinclair, and Pauli Paasonen
                                        Aerosol Research Discuss., https://doi.org/10.5194/ar-2025-18, https://doi.org/10.5194/ar-2025-18, 2025
                                    Revised manuscript accepted for AR 
                                    Short summary
                                    Short summary
                                            
                                                We trained machine learning models to estimate the number of aerosol particles large enough to form clouds and generated daily estimates for the entire globe. The models performed well in many continental regions but struggled in remote and marine areas. Still, this approach offers a way to quantify these particles in areas that lack direct measurements, helping us understand their influence on clouds and climate on a global scale.
                                            
                                            
                                        Jingye Ren, Songjian Zou, Honghao Xu, Guiquan Liu, Zhe Wang, Anran Zhang, Chuanfeng Zhao, Min Hu, Dongjie Shang, Lizi Tang, Ru-Jin Huang, Yele Sun, and Fang Zhang
                                        EGUsphere, https://doi.org/10.5194/egusphere-2025-1483, https://doi.org/10.5194/egusphere-2025-1483, 2025
                                    Preprint archived 
                                    Short summary
                                    Short summary
                                            
                                                In this study, a new framework of cloud condensation nuclei (CCN) prediction in polluted region has been developed and it achieves well prediction of hourly-to-yearly scale across North China Plain. The study reveals a significant long-term decreasing trend of CCN concentration at typical supersaturations due to a rapid reduction in aerosol concentrations from 2014 to 2018. This improvement of our new model would be helpful to aerosols climate effect assessment in models.
                                            
                                            
                                        Emmanuel Chevassus, Kirsten N. Fossum, Darius Ceburnis, Lu Lei, Chunshui Lin, Wei Xu, Colin O'Dowd, and Jurgita Ovadnevaite
                                    Atmos. Chem. Phys., 25, 4107–4129, https://doi.org/10.5194/acp-25-4107-2025, https://doi.org/10.5194/acp-25-4107-2025, 2025
                                    Short summary
                                    Short summary
                                            
                                                This study presents the first source apportionment of organic aerosol at Mace Head via high-resolution mass spectrometry. Introducing transfer entropy as a novel method reveals that aged organic aerosol originates from both open-ocean ozonolysis and local peat-burning oxidation. Methanesulfonic acid and organic sea spray both mirror phytoplankton activity, with the former closely tied to coccolithophore blooms and the latter linked to diatoms, chlorophytes, and cyanobacteria.
                                            
                                            
                                        Mingxue Li, Men Xia, Chunshui Lin, Yifan Jiang, Weihang Sun, Yurun Wang, Yingnan Zhang, Maoxia He, and Tao Wang
                                    Atmos. Chem. Phys., 25, 3753–3764, https://doi.org/10.5194/acp-25-3753-2025, https://doi.org/10.5194/acp-25-3753-2025, 2025
                                    Short summary
                                    Short summary
                                            
                                                Our field campaigns observed a strong diel pattern of chloroacetic acid as well as a strong correlation between its level and that of reactive chlorine species at a coastal site. Using quantum chemical calculations and box model simulation with an updated Master Chemical Mechanism, we found that the formation pathway of chloroacetic acid involved multiphase processes. Our study enhances understanding of atmospheric organic chlorine chemistry and emphasizes the importance of multiphase reactions.
                                            
                                            
                                        Tiantian Wang, Jun Zhang, Houssni Lamkaddam, Kun Li, Ka Yuen Cheung, Lisa Kattner, Erlend Gammelsæter, Michael Bauer, Zachary C. J. Decker, Deepika Bhattu, Rujin Huang, Rob L. Modini, Jay G. Slowik, Imad El Haddad, Andre S. H. Prevot, and David M. Bell
                                    Atmos. Chem. Phys., 25, 2707–2724, https://doi.org/10.5194/acp-25-2707-2025, https://doi.org/10.5194/acp-25-2707-2025, 2025
                                    Short summary
                                    Short summary
                                            
                                                Our study analyzes real-time emissions of organic vapors from solid fuel combustion. Using the mass spectrometer, we tested various fuels, finding higher emission factors for organic vapors from wood burning. Intermediate-volatility organic compounds constituted a significant fraction of emissions in solid fuel combustion. Statistical tests identified unique potential markers. Our insights benefit air quality, climate, and health, aiding accurate emission assessments.
                                            
                                            
                                        Wei Yuan, Ru-Jin Huang, Chao Luo, Lu Yang, Wenjuan Cao, Jie Guo, and Huinan Yang
                                    Atmos. Chem. Phys., 24, 13219–13230, https://doi.org/10.5194/acp-24-13219-2024, https://doi.org/10.5194/acp-24-13219-2024, 2024
                                    Short summary
                                    Short summary
                                            
                                                We characterized water-soluble oxidative potential (OP) levels in wintertime PM2.5 in the south and north of Beijing. Our results show that the volume-normalized dithiothreitol (DTTv) in the north was comparable to that in the south, while the mass-normalized dithiothreitol (DTTm) in the north was almost twice that in the south. Traffic-related emissions and biomass burning were the main sources of DTTv in the south, and traffic-related emissions contributed the most to DTTv in the north.
                                            
                                            
                                        Kirsten N. Fossum, Chunshui Lin, Niall O'Sullivan, Lu Lei, Stig Hellebust, Darius Ceburnis, Aqeel Afzal, Anja Tremper, David Green, Srishti Jain, Steigvilė Byčenkienė, Colin O'Dowd, John Wenger, and Jurgita Ovadnevaite
                                    Atmos. Chem. Phys., 24, 10815–10831, https://doi.org/10.5194/acp-24-10815-2024, https://doi.org/10.5194/acp-24-10815-2024, 2024
                                    Short summary
                                    Short summary
                                            
                                                The chemical composition and sources of submicron aerosol in the Dublin Port area were investigated over a month-long campaign. Two distinct types of ship emissions were identified and characterised: sulfate-rich plumes from the use of heavy fuel oil with scrubbers and organic-rich plumes from the use of low-sulfur fuels. The latter were more frequent, emitting double the particle number and having a typical V / Ni ratio for ship emission.
                                            
                                            
                                        Xinya Liu, Diego Alves Gouveia, Bas Henzing, Arnoud Apituley, Arjan Hensen, Danielle van Dinther, Rujin Huang, and Ulrike Dusek
                                    Atmos. Chem. Phys., 24, 9597–9614, https://doi.org/10.5194/acp-24-9597-2024, https://doi.org/10.5194/acp-24-9597-2024, 2024
                                    Short summary
                                    Short summary
                                            
                                                The vertical distribution of aerosol optical properties is important for their effect on climate. This is usually measured by lidar, which has limitations, most notably the assumption of a lidar ratio. Our study shows that routine surface-level aerosol measurements are able to predict this lidar ratio reasonably well within the lower layers of the atmosphere and thus provide a relatively simple and cost-effective method to improve lidar measurements.
                                            
                                            
                                        Karam Mansour, Stefano Decesari, Darius Ceburnis, Jurgita Ovadnevaite, Lynn M. Russell, Marco Paglione, Laurent Poulain, Shan Huang, Colin O'Dowd, and Matteo Rinaldi
                                    Earth Syst. Sci. Data, 16, 2717–2740, https://doi.org/10.5194/essd-16-2717-2024, https://doi.org/10.5194/essd-16-2717-2024, 2024
                                    Short summary
                                    Short summary
                                            
                                                We propose and evaluate machine learning predictive algorithms to model freshly formed biogenic methanesulfonic acid and sulfate concentrations. The long-term constructed dataset covers the North Atlantic at an unprecedented resolution. The improved parameterization of biogenic sulfur aerosols at regional scales is essential for determining their radiative forcing, which could help further understand marine-aerosol–cloud interactions and reduce uncertainties in climate models
                                            
                                            
                                        Xinya Liu, Bas Henzing, Arjan Hensen, Jan Mulder, Peng Yao, Danielle van Dinther, Jerry van Bronckhorst, Rujin Huang, and Ulrike Dusek
                                    Atmos. Chem. Phys., 24, 3405–3420, https://doi.org/10.5194/acp-24-3405-2024, https://doi.org/10.5194/acp-24-3405-2024, 2024
                                    Short summary
                                    Short summary
                                            
                                                We evaluated the time-of-flight aerosol chemical speciation monitor (TOF-ACSM) following the implementation of the PM2.5 aerodynamic lens and a capture vaporizer (CV). The results showed that it significantly improved the accuracy and precision of ACSM in the field observations. The paper elucidates the measurement outcomes of various instruments and provides an analysis of their biases. This comprehensive evaluation is expected to benefit the ACSM community and other aerosol field measurements.
                                            
                                            
                                        Feifan Yan, Hang Su, Yafang Cheng, Rujin Huang, Hong Liao, Ting Yang, Yuanyuan Zhu, Shaoqing Zhang, Lifang Sheng, Wenbin Kou, Xinran Zeng, Shengnan Xiang, Xiaohong Yao, Huiwang Gao, and Yang Gao
                                    Atmos. Chem. Phys., 24, 2365–2376, https://doi.org/10.5194/acp-24-2365-2024, https://doi.org/10.5194/acp-24-2365-2024, 2024
                                    Short summary
                                    Short summary
                                            
                                                PM2.5 pollution is a major air quality issue deteriorating human health, and previous studies mostly focus on regions like the North China Plain and Yangtze River Delta. However, the characteristics of PM2.5 concentrations between these two regions are studied less often. Focusing on the transport corridor region, we identify an interesting seesaw transport phenomenon with stagnant weather conditions, conducive to PM2.5 accumulation over this region, resulting in large health effects.
                                            
                                            
                                        Shuzheng Guo, Chunxiang Ye, Weili Lin, Yi Chen, Limin Zeng, Xuena Yu, Jinhui Cui, Chong Zhang, Jing Duan, Haobin Zhong, Rujin Huang, Xuguang Chi, Wei Nie, and Aijun Ding
                                        EGUsphere, https://doi.org/10.5194/egusphere-2024-262, https://doi.org/10.5194/egusphere-2024-262, 2024
                                    Preprint archived 
                                    Short summary
                                    Short summary
                                            
                                                @Tibet field campaigns 2021 discovered surprisingly high levels and activity contributions of oxygenated volatile organic compounds on the southeast of the Tibetan Plateau, which suggests that OVOCs may play a larger role in the chemical reactions that occur in high-altitude regions than previously thought.
                                            
                                            
                                        Yuquan Gong, Ru-Jin Huang, Lu Yang, Ting Wang, Wei Yuan, Wei Xu, Wenjuan Cao, Yang Wang, and Yongjie Li
                                    Atmos. Chem. Phys., 23, 15197–15207, https://doi.org/10.5194/acp-23-15197-2023, https://doi.org/10.5194/acp-23-15197-2023, 2023
                                    Short summary
                                    Short summary
                                            
                                                This study reveals the large day–night differences in brown carbon (BrC) chromophore composition, which was not known previously. The results provide insights into the effects of atmospheric processes and emissions on BrC composition.
                                            
                                            
                                        Jiyeon Park, Hyojin Kang, Yeontae Gim, Eunho Jang, Ki-Tae Park, Sangjong Park, Chang Hoon Jung, Darius Ceburnis, Colin O'Dowd, and Young Jun Yoon
                                    Atmos. Chem. Phys., 23, 13625–13646, https://doi.org/10.5194/acp-23-13625-2023, https://doi.org/10.5194/acp-23-13625-2023, 2023
                                    Short summary
                                    Short summary
                                            
                                                We measured the number size distribution of 2.5–300 nm particles and cloud condensation nuclei (CCN) number concentrations at King Sejong Station on the Antarctic Peninsula continuously from 1 January to 31 December 2018. During the pristine and clean periods, 97 new particle formation (NPF) events were detected. For 83 of these, CCN concentrations increased by 2 %–268 % (median 44 %) following 1 to 36 h (median 8 h) after NPF events.
                                            
                                            
                                        Yifang Gu, Ru-Jin Huang, Jing Duan, Wei Xu, Chunshui Lin, Haobin Zhong, Ying Wang, Haiyan Ni, Quan Liu, Ruiguang Xu, Litao Wang, and Yong Jie Li
                                    Atmos. Chem. Phys., 23, 5419–5433, https://doi.org/10.5194/acp-23-5419-2023, https://doi.org/10.5194/acp-23-5419-2023, 2023
                                    Short summary
                                    Short summary
                                            
                                                Secondary organic aerosol (SOA) can be produced by various pathways, but its formation mechanisms are unclear. Observations were conducted in the North China Plain during a highly oxidizing atmosphere in summer. We found that fast photochemistry dominated SOA formation during daytime. Two types of aqueous-phase chemistry (nocturnal and daytime processing) take place at high relative humidity. The potential transformation from primary organic aerosol (POA) to SOA was also an important pathway.
                                            
                                            
                                        Chunshui Lin, Ru-Jin Huang, Haobin Zhong, Jing Duan, Zixi Wang, Wei Huang, and Wei Xu
                                    Atmos. Chem. Phys., 23, 3595–3607, https://doi.org/10.5194/acp-23-3595-2023, https://doi.org/10.5194/acp-23-3595-2023, 2023
                                    Short summary
                                    Short summary
                                            
                                                The complex interaction between O3 and PM2.5, coupled with the topology of the Fenwei Plain and the evolution of the boundary layer height, highlights the challenges in further reducing particulate pollution in winter despite years of efforts to reduce emissions. Through scenario analysis in a chemical box model constrained by observation, we show the co-benefits of reducing NOx and VOCs simultaneously in reducing ozone and SOA.
                                            
                                            
                                        Huanhuan Zhang, Rui Li, Chengpeng Huang, Xiaofei Li, Shuwei Dong, Fu Wang, Tingting Li, Yizhu Chen, Guohua Zhang, Yan Ren, Qingcai Chen, Ru-jin Huang, Siyu Chen, Tao Xue, Xinming Wang, and Mingjin Tang
                                    Atmos. Chem. Phys., 23, 3543–3559, https://doi.org/10.5194/acp-23-3543-2023, https://doi.org/10.5194/acp-23-3543-2023, 2023
                                    Short summary
                                    Short summary
                                            
                                                This work investigated the seasonal variation of aerosol Fe solubility for coarse and fine particles in Xi’an, a megacity in northwestern China severely affected by anthropogenic emission and desert dust aerosol. In addition, we discussed in depth what controlled aerosol Fe solubility at different seasons for coarse and fine particles.
                                            
                                            
                                        Ville Leinonen, Harri Kokkola, Taina Yli-Juuti, Tero Mielonen, Thomas Kühn, Tuomo Nieminen, Simo Heikkinen, Tuuli Miinalainen, Tommi Bergman, Ken Carslaw, Stefano Decesari, Markus Fiebig, Tareq Hussein, Niku Kivekäs, Radovan Krejci, Markku Kulmala, Ari Leskinen, Andreas Massling, Nikos Mihalopoulos, Jane P. Mulcahy, Steffen M. Noe, Twan van Noije, Fiona M. O'Connor, Colin O'Dowd, Dirk Olivie, Jakob B. Pernov, Tuukka Petäjä, Øyvind Seland, Michael Schulz, Catherine E. Scott, Henrik Skov, Erik Swietlicki, Thomas Tuch, Alfred Wiedensohler, Annele Virtanen, and Santtu Mikkonen
                                    Atmos. Chem. Phys., 22, 12873–12905, https://doi.org/10.5194/acp-22-12873-2022, https://doi.org/10.5194/acp-22-12873-2022, 2022
                                    Short summary
                                    Short summary
                                            
                                                We provide the first extensive comparison of detailed aerosol size distribution trends between in situ observations from Europe and five different earth system models. We investigated aerosol modes (nucleation, Aitken, and accumulation) separately and were able to show the differences between measured and modeled trends and especially their seasonal patterns. The differences in model results are likely due to complex effects of several processes instead of certain specific model features.
                                            
                                            
                                        Meng Wang, Yusen Duan, Wei Xu, Qiyuan Wang, Zhuozhi Zhang, Qi Yuan, Xinwei Li, Shuwen Han, Haijie Tong, Juntao Huo, Jia Chen, Shan Gao, Zhongbiao Wu, Long Cui, Yu Huang, Guangli Xiu, Junji Cao, Qingyan Fu, and Shun-cheng Lee
                                    Atmos. Chem. Phys., 22, 12789–12802, https://doi.org/10.5194/acp-22-12789-2022, https://doi.org/10.5194/acp-22-12789-2022, 2022
                                    Short summary
                                    Short summary
                                            
                                                In this study, we report the long-term measurement of organic carbon (OC) and elementary carbon (EC) in PM2.5 with hourly time resolution conducted at a regional site in Shanghai from 2016 to 2020. The results from this study provide critical information about the long-term trend of carbonaceous aerosol, in particular secondary OC, in one of the largest megacities in the world and are helpful for developing pollution control measures from a long-term planning perspective.
                                            
                                            
                                        Marta Via, Gang Chen, Francesco Canonaco, Kaspar R. Daellenbach, Benjamin Chazeau, Hasna Chebaicheb, Jianhui Jiang, Hannes Keernik, Chunshui Lin, Nicolas Marchand, Cristina Marin, Colin O'Dowd, Jurgita Ovadnevaite, Jean-Eudes Petit, Michael Pikridas, Véronique Riffault, Jean Sciare, Jay G. Slowik, Leïla Simon, Jeni Vasilescu, Yunjiang Zhang, Olivier Favez, André S. H. Prévôt, Andrés Alastuey, and María Cruz Minguillón
                                    Atmos. Meas. Tech., 15, 5479–5495, https://doi.org/10.5194/amt-15-5479-2022, https://doi.org/10.5194/amt-15-5479-2022, 2022
                                    Short summary
                                    Short summary
                                            
                                                This work presents the differences resulting from two techniques (rolling and seasonal) of the positive matrix factorisation model that can be run for organic aerosol source apportionment. The current state of the art suggests that the rolling technique is more accurate, but no proof of its effectiveness has been provided yet. This paper tackles this issue in the context of a synthetic dataset and a multi-site real-world comparison.
                                            
                                            
                                        Jing Duan, Ru-Jin Huang, Yifang Gu, Chunshui Lin, Haobin Zhong, Wei Xu, Quan Liu, Yan You, Jurgita Ovadnevaite, Darius Ceburnis, Thorsten Hoffmann, and Colin O'Dowd
                                    Atmos. Chem. Phys., 22, 10139–10153, https://doi.org/10.5194/acp-22-10139-2022, https://doi.org/10.5194/acp-22-10139-2022, 2022
                                    Short summary
                                    Short summary
                                            
                                                Biomass-burning-influenced oxygenated organic aerosol (OOA-BB), formed from the photochemical oxidation and aging of biomass burning OA (BBOA), was resolved in urban Xi’an. The aqueous-phase processed oxygenated OA (aq-OOA) concentration was more dependent on secondary inorganic aerosol (SIA) content and aerosol liquid water content (ALWC). The increased aq-OOA contribution during SIA-enhanced periods likely reflects OA evolution due to the addition of alcohol or peroxide groups
                                            
                                            
                                        Haobin Zhong, Ru-Jin Huang, Chunshui Lin, Wei Xu, Jing Duan, Yifang Gu, Wei Huang, Haiyan Ni, Chongshu Zhu, Yan You, Yunfei Wu, Renjian Zhang, Jurgita Ovadnevaite, Darius Ceburnis, and Colin D. O'Dowd
                                    Atmos. Chem. Phys., 22, 9513–9524, https://doi.org/10.5194/acp-22-9513-2022, https://doi.org/10.5194/acp-22-9513-2022, 2022
                                    Short summary
                                    Short summary
                                            
                                                To investigate the physico-chemical properties of aerosol transported from major pollution regions in China, observations were conducted ~200 m above the ground at the junction location of the two key pollution areas. We found that the formation efficiency, oxidation state and production rate of secondary aerosol were different in the transport sectors from different pollution regions, and they were largely enhanced by the regional long-distance transport.
                                            
                                            
                                        Youwei Hong, Xinbei Xu, Dan Liao, Taotao Liu, Xiaoting Ji, Ke Xu, Chunyang Liao, Ting Wang, Chunshui Lin, and Jinsheng Chen
                                    Atmos. Chem. Phys., 22, 7827–7841, https://doi.org/10.5194/acp-22-7827-2022, https://doi.org/10.5194/acp-22-7827-2022, 2022
                                    Short summary
                                    Short summary
                                            
                                                Secondary organic aerosol (SOA) simulation remains uncertain, due to the unknown SOA formation mechanisms. Aerosol samples with a 4 h time resolution were collected, along with online measurements of aerosol chemical compositions and meteorological parameters. We found that anthropogenic emissions, atmospheric oxidation capacity and halogen chemistry have significant effects on the formation of biogenic SOA (BSOA). The findings of this study are helpful to better explore the missed SOA sources.
                                            
                                            
                                        Chunshui Lin, Darius Ceburnis, Anna Trubetskaya, Wei Xu, William Smith, Stig Hellebust, John Wenger, Colin O'Dowd, and Jurgita Ovadnevaite
                                    Atmos. Meas. Tech., 14, 6905–6916, https://doi.org/10.5194/amt-14-6905-2021, https://doi.org/10.5194/amt-14-6905-2021, 2021
                                    Short summary
                                    Short summary
                                            
                                                Source apportionment of solid-fuel-burning emissions can be complicated by the use of different fuels, stoves, and burning conditions. Here, the organic aerosol mass spectra produced from burning a range of solid fuels in several stoves were compared. This study  accounts for the source variability and provides better constraints on the primary factor contributions to the ambient organic aerosol estimations, holding significant implications for public health and policymakers.
                                            
                                            
                                        Gloria Titos, María A. Burgos, Paul Zieger, Lucas Alados-Arboledas, Urs Baltensperger, Anne Jefferson, James Sherman, Ernest Weingartner, Bas Henzing, Krista Luoma, Colin O'Dowd, Alfred Wiedensohler, and Elisabeth Andrews
                                    Atmos. Chem. Phys., 21, 13031–13050, https://doi.org/10.5194/acp-21-13031-2021, https://doi.org/10.5194/acp-21-13031-2021, 2021
                                    Short summary
                                    Short summary
                                            
                                                This paper investigates the impact of water uptake on aerosol optical properties, in particular the aerosol light-scattering coefficient. Although in situ measurements are performed at low relative humidity (typically at 
RH < 40 %), to address the climatic impact of aerosol particles it is necessary to take into account the effect that water uptake may have on the aerosol optical properties.
                                            
                                            
                                        Yandong Tong, Veronika Pospisilova, Lu Qi, Jing Duan, Yifang Gu, Varun Kumar, Pragati Rai, Giulia Stefenelli, Liwei Wang, Ying Wang, Haobin Zhong, Urs Baltensperger, Junji Cao, Ru-Jin Huang, André S. H. Prévôt, and Jay G. Slowik
                                    Atmos. Chem. Phys., 21, 9859–9886, https://doi.org/10.5194/acp-21-9859-2021, https://doi.org/10.5194/acp-21-9859-2021, 2021
                                    Short summary
                                    Short summary
                                            
                                                We investigate SOA sources and formation processes by a field deployment of the EESI-TOF-MS and L-TOF AMS in Beijing in late autumn and early winter. Our study shows that the sources and processes giving rise to haze events in Beijing are variable and seasonally dependent: (1) in the heating season, SOA formation is driven by oxidation of aromatics from solid fuel combustion; and (2) under high-NOx and RH conditions, aqueous-phase chemistry can be a major contributor to SOA formation.
                                            
                                            
                                        Kai Wang, Ru-Jin Huang, Martin Brüggemann, Yun Zhang, Lu Yang, Haiyan Ni, Jie Guo, Meng Wang, Jiajun Han, Merete Bilde, Marianne Glasius, and Thorsten Hoffmann
                                    Atmos. Chem. Phys., 21, 9089–9104, https://doi.org/10.5194/acp-21-9089-2021, https://doi.org/10.5194/acp-21-9089-2021, 2021
                                    Short summary
                                    Short summary
                                            
                                                Here we present the detailed molecular composition of the organic aerosol collected in three eastern Chinese cities from north to south, Changchun, Shanghai and Guangzhou, by applying LC–Orbitrap analysis. Accordingly, the aromaticity degree of chemical compounds decreases from north to south, while the oxidation degree increases from north to south, which can be explained by the different anthropogenic emissions and photochemical oxidation processes.
                                            
                                            
                                        Wei Xu, Kirsten N. Fossum, Jurgita Ovadnevaite, Chunshui Lin, Ru-Jin Huang, Colin O'Dowd, and Darius Ceburnis
                                    Atmos. Chem. Phys., 21, 8655–8675, https://doi.org/10.5194/acp-21-8655-2021, https://doi.org/10.5194/acp-21-8655-2021, 2021
                                    Short summary
                                    Short summary
                                            
                                                Cloud condensation nuclei (CCN) are an important topic in atmospheric studies, especially for evaluating the climate impact of aerosol. Here in this study, CCN closure is studied by using chemical composition based on an aerosol mass spectrometer (AMS) and hygroscopicity growth measurements based on a humidified tandem differential mobility analyzer (HTDMA) at the Mace Head atmospheric research station.
                                            
                                            
                                        Chao Peng, Patricia N. Razafindrambinina, Kotiba A. Malek, Lanxiadi Chen, Weigang Wang, Ru-Jin Huang, Yuqing Zhang, Xiang Ding, Maofa Ge, Xinming Wang, Akua A. Asa-Awuku, and Mingjin Tang
                                    Atmos. Chem. Phys., 21, 7135–7148, https://doi.org/10.5194/acp-21-7135-2021, https://doi.org/10.5194/acp-21-7135-2021, 2021
                                    Short summary
                                    Short summary
                                            
                                                Organosulfates are important constituents in tropospheric aerosol particles, but their hygroscopic properties and cloud condensation nuclei activities are not well understood. In our work, three complementary techniques were employed to investigate the interactions of 11 organosulfates with water vapor under sub- and supersaturated conditions.
                                            
                                            
                                        Wei Yuan, Ru-Jin Huang, Lu Yang, Ting Wang, Jing Duan, Jie Guo, Haiyan Ni, Yang Chen, Qi Chen, Yongjie Li, Ulrike Dusek, Colin O'Dowd, and Thorsten Hoffmann
                                    Atmos. Chem. Phys., 21, 3685–3697, https://doi.org/10.5194/acp-21-3685-2021, https://doi.org/10.5194/acp-21-3685-2021, 2021
                                    Short summary
                                    Short summary
                                            
                                                We characterized the seasonal variations in nitrated aromatic compounds (NACs) in composition, sources, and their light absorption contribution to brown carbon (BrC) aerosol in Xi'an, Northwest China. Our results show that secondary formation and vehicular emission were dominant sources in summer (~80 %), and biomass burning and coal combustion were major sources in winter (~75 %), and they indicate that the composition and sources of NACs have a profound impact on the light absorption of BrC
                                            
                                            
                                        Francesco Canonaco, Anna Tobler, Gang Chen, Yulia Sosedova, Jay Gates Slowik, Carlo Bozzetti, Kaspar Rudolf Daellenbach, Imad El Haddad, Monica Crippa, Ru-Jin Huang, Markus Furger, Urs Baltensperger, and André Stephan Henry Prévôt
                                    Atmos. Meas. Tech., 14, 923–943, https://doi.org/10.5194/amt-14-923-2021, https://doi.org/10.5194/amt-14-923-2021, 2021
                                    Short summary
                                    Short summary
                                            
                                                Long-term ambient aerosol mass spectrometric data were analyzed with a statistical model (PMF) to obtain source contributions and fingerprints. The new aspects of this paper involve time-dependent source fingerprints by a rolling technique and the replacement of the full visual inspection of each run by a user-defined set of criteria to monitor the quality of each of these runs more efficiently. More reliable sources will finally provide better instruments for political mitigation strategies.
                                            
                                            
                                        Pragati Rai, Jay G. Slowik, Markus Furger, Imad El Haddad, Suzanne Visser, Yandong Tong, Atinderpal Singh, Günther Wehrle, Varun Kumar, Anna K. Tobler, Deepika Bhattu, Liwei Wang, Dilip Ganguly, Neeraj Rastogi, Ru-Jin Huang, Jaroslaw Necki, Junji Cao, Sachchida N. Tripathi, Urs Baltensperger, and André S. H. Prévôt
                                    Atmos. Chem. Phys., 21, 717–730, https://doi.org/10.5194/acp-21-717-2021, https://doi.org/10.5194/acp-21-717-2021, 2021
                                    Short summary
                                    Short summary
                                            
                                                We present a simple conceptual framework based on elemental size distributions and enrichment factors that allows for a characterization of major sources, site-to-site similarities, and local differences and the identification of key information required for efficient policy development. Absolute concentrations are by far the highest in Delhi, followed by Beijing, and then the European cities.
                                            
                                            
                                        Haiyan Ni, Ru-Jin Huang, Max M. Cosijn, Lu Yang, Jie Guo, Junji Cao, and Ulrike Dusek
                                    Atmos. Chem. Phys., 20, 16041–16053, https://doi.org/10.5194/acp-20-16041-2020, https://doi.org/10.5194/acp-20-16041-2020, 2020
                                    Short summary
                                    Short summary
                                            
                                                We investigated sources of carbonaceous aerosols in Beijing and Xi'an during severe winter haze. Elemental carbon (EC) was dominated by vehicle emissions in Xi’an and coal burning in Beijing. Organic carbon (OC) increment during haze days was driven by the increase in primary and secondary OC (SOC). SOC was more from fossil sources in Beijing than Xi’an, especially during haze days. In Xi’an, no strong day–night differences in EC or OC sources suggest a large accumulation of particles.
                                            
                                            
                                        Chao Peng, Yu Wang, Zhijun Wu, Lanxiadi Chen, Ru-Jin Huang, Weigang Wang, Zhe Wang, Weiwei Hu, Guohua Zhang, Maofa Ge, Min Hu, Xinming Wang, and Mingjin Tang
                                    Atmos. Chem. Phys., 20, 13877–13903, https://doi.org/10.5194/acp-20-13877-2020, https://doi.org/10.5194/acp-20-13877-2020, 2020
                            Cited articles
                        
                        An, Z. S., Huang, R.-J., Zhang, R. Y., Tie, X. X., Li, G. H., Cao, J. J., Zhou, W. J., Shi, Z. G., Han, Y. M., Gu, Z. L., and Ji, Y. M.: Severe haze in northern China: A synergy of anthropogenic emissions and atmospheric processes, P. Natl. Acad. Sci. USA, 116, 8657–8666, https://doi.org/10.1073/pnas.1900125116, 2019. 
                    
                
                        
                        Burnett, R., Chen, H., Szyszkowicz, M., Fann, N., Hubbell, B., Pope, C. A., Apte, J. S., Brauer, M., Cohen, A., Weichenthal, S., Coggins, J., Di, Q., Brunekreef, B., Frostad, J., Lim, S. S., Kan, H., Walker, K. D., Thurston, G. D., Hayes, R. B., Lim, C. C., Turner, M. C., Jerrett, M., Krewski, D., Gapstur, S. M., Diver, W. R., Ostro, B., Goldberg, D., Crouse, D. L., Martin, R. V., Peters, P., Pinault, L., Tjepkema, M., van Donkelaar, A., Villeneuve, P. J., Miller, A. B., Yin, P., Zhou, M., Wang, L., Janssen, N. A. H., Marra, M., Atkinson, R. W., Tsang, H., Quoc Thach, T., Cannon, J. B., Allen, R. T., Hart, J. E., Laden, F., Cesaroni, G., Forastiere, F., Weinmayr, G., Jaensch, A., Nagel, G., Concin, H., and Spadaro, J. V.: Global estimates of mortality associated with long-term exposure to outdoor fine particulate matter, P. Natl. Acad. Sci. USA, 115, 9592–9597, https://doi.org/10.1073/pnas.1803222115, 2018. 
                    
                
                        
                        Cai, M., Huang, S., Liang, B., Sun, Q., Liu, L., Yuan, B., Shao, M., Hu, W., Chen, W., Song, Q., Li, W., Peng, Y., Wang, Z., Chen, D., Tan, H., Xu, H., Li, F., Deng, X., Deng, T., Sun, J., and Zhao, J.: Measurement report: Distinct size dependence and diurnal variation in organic aerosol hygroscopicity, volatility, and cloud condensation nuclei activity at a rural site in the Pearl River Delta (PRD) region, China, Atmos. Chem. Phys., 22, 8117–8136, https://doi.org/10.5194/acp-22-8117-2022, 2022. 
                    
                
                        
                        Cai, W., Li, K., Liao, H., Wang, H., and Wu, L.: Weather conditions conducive to Beijing severe haze more frequent under climate change, Nat. Clim. Change, 7, 257–263, https://doi.org/10.1038/nclimate3249, 2017. 
                    
                
                        
                        Canagaratna, M. R., Jayne, J. T., Jiménez, J. L., Allan, J. D., Alfarra, M. R., Zhang, Q., Onasch, T. B., Drewnick, F., Coe, H., Middlebrook, A., Delia, A., Williams, L. R., Trimborn, A. M., Northway, M. J., DeCarlo, P. F., Kolb, C. E., Davidovits, P., and Worsnop, D. R.: Chemical and Microphysical Characterization of Ambient Aerosols with the Aerodyne Aerosol Mass Spectrometer, Mass Spectrom. Rev., 26, 185–222, 2007. 
                    
                
                        
                        Chen, Y., Wang, Y., Nenes, A., Wild, O., Song, S., Hu, D., Liu, D., He, J., Hildebrandt Ruiz, L., Apte, J. S., Gunthe, S. S., and Liu, P.: Ammonium Chloride Associated Aerosol Liquid Water Enhances Haze in Delhi, India, Environ. Sci. Technol., 56, 7163–7173, https://doi.org/10.1021/acs.est.2c00650, 2022. 
                    
                
                        
                        Chen, Z., Chen, D., Zhao, C., Kwan, M.-P., Cai, J., Zhuang, Y., Zhao, B., Wang, X., Chen, B., Yang, J., Li, R., He, B., Gao, B., Wang, K., and Xu, B.: Influence of meteorological conditions on PM2.5 concentrations across China: A review of methodology and mechanism, Environ. Int., 139, 105558, https://doi.org/10.1016/j.envint.2020.105558, 2020. 
                    
                
                        
                        Chu, B., Ma, Q., Liu, J., Ma, J., Zhang, P., Chen, T., Feng, Q., Wang, C., Yang, N., Ma, H., Ma, J., Russell, A. G., and He, H.: Air Pollutant Correlations in China: Secondary Air Pollutant Responses to NOx and SO2 Control, Environ. Sci. Tech. Let., 7, 695–700, https://doi.org/10.1021/acs.estlett.0c00403, 2020. 
                    
                
                        
                        Craig, R. L. and Ault, A. P.: Aerosol Acidity: Direct Measurement from a Spectroscopic Method, in: Multiphase Environmental Chemistry in the Atmosphere, ACS Symposium Series, 1299, American Chemical Society, 171–191, https://doi.org/10.1021/bk-2018-1299.ch009, 2018. 
                    
                
                        
                        Duan, J.: Size-resolved OA composition in winter Xi'an between different years, East Asian Paleoenvironmental Science Database [data set], https://doi.org/10.12262/IEECAS.EAPSD2024001, 2024. 
                    
                
                        
                        Duan, J., Huang, R.-J., Gu, Y., Lin, C., Zhong, H., Xu, W., Liu, Q., You, Y., Ovadnevaite, J., Ceburnis, D., Hoffmann, T., and O'Dowd, C.: Measurement report: Large contribution of biomass burning and aqueous-phase processes to the wintertime secondary organic aerosol formation in Xi'an, Northwest China, Atmos. Chem. Phys., 22, 10139–10153, https://doi.org/10.5194/acp-22-10139-2022, 2022. 
                    
                
                        
                        Elser, M., Huang, R.-J., Wolf, R., Slowik, J. G., Wang, Q., Canonaco, F., Li, G., Bozzetti, C., Daellenbach, K. R., Huang, Y., Zhang, R., Li, Z., Cao, J., Baltensperger, U., El-Haddad, I., and Prévôt, A. S. H.: New insights into PM2.5 chemical composition and sources in two major cities in China during extreme haze events using aerosol mass spectrometry, Atmos. Chem. Phys., 16, 3207–3225, https://doi.org/10.5194/acp-16-3207-2016, 2016. 
                    
                
                        
                        Fontes, T., Li, P. L., Barros, N., and Zhao, P. J.: Trends of PM2.5 concentrations in China: A long term approach, J. Environ. Manage., 196, 719–732, https://doi.org/10.1016/j.jenvman.2017.03.074, 2017. 
                    
                
                        
                        Fountoukis, C. and Nenes, A.: ISORROPIA II: a computationally efficient thermodynamic equilibrium model for K+–Ca2+–Mg2+–  –Na+– – –Cl−–H2O aerosols, Atmos. Chem. Phys., 7, 4639–4659, https://doi.org/10.5194/acp-7-4639-2007, 2007. 
                    
                
                        
                        Grange, S. K., Carslaw, D. C., Lewis, A. C., Boleti, E., and Hueglin, C.: Random forest meteorological normalisation models for Swiss PM10 trend analysis, Atmos. Chem. Phys., 18, 6223–6239, https://doi.org/10.5194/acp-18-6223-2018, 2018. 
                    
                
                        
                        Gu, Y., Huang, R.-J., Duan, J., Xu, W., Lin, C., Zhong, H., Wang, Y., Ni, H., Liu, Q., Xu, R., Wang, L., and Li, Y. J.: Multiple pathways for the formation of secondary organic aerosol in the North China Plain in summer, Atmos. Chem. Phys., 23, 5419–5433, https://doi.org/10.5194/acp-23-5419-2023, 2023. 
                    
                
                        
                        He, Y., Akherati, A., Nah, T., Ng, N. L., Garofalo, L. A., Farmer, D. K., Shiraiwa, M., Zaveri, R. A., Cappa, C. D., Pierce, J. R., and Jathar, S. H.: Particle Size Distribution Dynamics Can Help Constrain the Phase State of Secondary Organic Aerosol, Environ. Sci. Technol., 55, 1466–1476, https://doi.org/10.1021/acs.est.0c05796, 2021. 
                    
                
                        
                        Herrmann, H., Schaefer, T., Tilgner, A., Styler, S., Weller, C., Teich, M., and Otto, T.: Tropospheric Aqueous-Phase Chemistry: Kinetics, Mechanisms, and Its Coupling to a Changing Gas Phase, Chem. Rev., 115, 4259–4334, https://doi.org/10.1021/cr500447k, 2015. 
                    
                
                        
                        Huang, R.-J., Zhang, Y. L., Bozzetti, C., Ho, K.-F., Cao, J. J., Han, Y. M., Daellenbach, K. R., Slowik, J. G., Platt, S. M., Canonaco, F., Zotter, P., Wolf, R., Pieber, S. M., Bruns, E. A., Crippa, M., Ciarelli, G., Piazzalunga, A., Schwikowski, M., Abbaszade, G., Schnelle-Kreis, J., Zimmermann, R., An, Z., Szidat, S., Baltensperger, U., Haddad, I. E., and Prévôt, A. S. H.: High secondary aerosol contribution to particulate pollution during haze events in China, Nature, 514, 218–222, https://doi.org/10.1038/nature13774, 2014. 
                    
                
                        
                        Huang, R.-J., Wang, Y., Cao, J., Lin, C., Duan, J., Chen, Q., Li, Y., Gu, Y., Yan, J., Xu, W., Fröhlich, R., Canonaco, F., Bozzetti, C., Ovadnevaite, J., Ceburnis, D., Canagaratna, M. R., Jayne, J., Worsnop, D. R., El-Haddad, I., Prévôt, A. S. H., and O'Dowd, C. D.: Primary emissions versus secondary formation of fine particulate matter in the most polluted city (Shijiazhuang) in North China, Atmos. Chem. Phys., 19, 2283–2298, https://doi.org/10.5194/acp-19-2283-2019, 2019. 
                    
                
                        
                        Jian, L., Zhao, Y., Zhu, Y. P., Zhang, M. B., and Bertolatti, D.: An application of arima model to predict submicron particle concentrations from meteorological factors at a busy roadside in hangzhou, China, Sci. Total Environ., 426, 336–345, 2012. 
                    
                
                        
                        Kim, N., Yum, S. S., Park, M., Park, J. S., Shin, H. J., and Ahn, J. Y.: Hygroscopicity of urban aerosols and its link to size-resolved chemical composition during spring and summer in Seoul, Korea, Atmos. Chem. Phys., 20, 11245–11262, https://doi.org/10.5194/acp-20-11245-2020, 2020. 
                    
                
                        
                        Kuang, Y., He, Y., Xu, W. Y., Yuan, B., Zhang, G., Ma, Z. Q., Wu, C. H., Wang, C. M., Wang, S. H., Zhang, S. Y., Tao, J. C., Ma, N., Su, H., Cheng, Y. F., Shao, M., and Sun, Y. L.: Photochemical aqueous-phase reactions induce rapid daytime formation of oxygenated organic aerosol on the North China Plain, Environ. Sci. Technol., 54, 3849–3860, https://doi.org/10.1021/acs.est.9b06836, 2020. 
                    
                
                        
                        Li, J., Gao, W., Cao, L., Xiao, Y., Zhang, Y., Zhao, S., Liu, Z., Liu, Z., Tang, G., Ji, D., Hu, B., Song, T., He, L., Hu, M., and Wang, Y. S.: Significant changes in autumn and winter aerosol composition and sources in Beijing from 2012 to 2018: Effects of clean air actions, Environ. Pollut., 268, 115855, https://doi.org/10.1016/j.envpol.2020.115855, 2021. 
                    
                
                        
                        Lin, C., Huang, R.-J., Zhong, H., Duan, J., Wang, Z., Huang, W., and Xu, W.: Elucidating ozone and PM2.5 pollution in the Fenwei Plain reveals the co-benefits of controlling precursor gas emissions in winter haze, Atmos. Chem. Phys., 23, 3595–3607, https://doi.org/10.5194/acp-23-3595-2023, 2023. 
                    
                
                        
                        Liu, Y., Wu, Z., Huang, X., Shen, H., Bai, Y., Qiao, K., Meng, X., Hu, W., Tang, M., and He, L.: Aerosol phase state and its link to chemical composition and liquid water content in a subtropical coastal megacity, Environ. Sci. Technol., 53, 5027–5033, https://doi.org/10.1021/acs.est.9b01196, 2019. 
                    
                
                        
                        Liu, Y., Feng, Z., Zheng, F., Bao, X., Liu, P., Ge, Y., Zhao, Y., Jiang, T., Liao, Y., Zhang, Y., Fan, X., Yan, C., Chu, B., Wang, Y., Du, W., Cai, J., Bianchi, F., Petäjä, T., Mu, Y., He, H., and Kulmala, M.: Ammonium nitrate promotes sulfate formation through uptake kinetic regime, Atmos. Chem. Phys., 21, 13269–13286, https://doi.org/10.5194/acp-21-13269-2021, 2021. 
                    
                
                        
                        Liu, Y. C., Wu, Z. J., Qiu, Y. T., Tian, P., Liu, Q., Chen, Y., Song, M., and Hu, M.: Enhanced nitrate fraction: Enabling urban aerosol particles to remain in a liquid state at reduced relative humidity, Geophys. Res. Lett., 50, e2023GL105505, https://doi.org/10.1029/2023GL105505, 2023. 
                    
                
                        
                        Lundberg, S. M., Erion, G., Chen, H., DeGrave, A., Prutkin, J. M., Nair, B., Katz, R., Himmelfarb, J., Bansal, N., and Lee, S.-I.: From local explanations to global understanding with explainable AI for trees, Nat. Mach. Intell., 2, 56–67, https://doi.org/10.1038/s42256-019-0138-9, 2020. 
                    
                
                        
                        Lv, S. J., Wu, C., Wang, F. L., Liu, X. D., Zhang, S., Chen, Y. B., Zhang, F., Yang, Y., Wang, H. L., Huang, C., Fu, Q. Y., Duan, Y. S., and Wang, G. H.: Nitrate-enhanced gas-to-particle-phase partitioning of water-soluble organic compounds in Chinese urban atmosphere: implications for secondary organic aerosol formation, Environ. Sci. Tech. Let., 10, 14–20, https://doi.org/10.1021/acs.estlett.2c00894, 2023. 
                    
                
                        
                        Middlebrook, A. M., Bahreini, R., Jimenez, J. L., and Canagaratna, M. R.: Evaluation of composition-dependent collection efficiencies for the Aerodyne Aerosol Mass Spectrometer using field data, Aerosol Sci. Tech., 46, 258–271, https://doi.org/10.1080/02786826.2011.620041, 2012. 
                    
                
                        
                        Paatero, P.: The multilinear engine: a table-driven, least squares program for solving multilinear problems, including the n-way parallel factor analysis model, J. Comput. Graph. Stat., 8, 854–888, https://doi.org/10.1080/10618600.1999.10474853, 1999. 
                    
                
                        
                        Paatero, P. and Tapper, U.: Positive Matrix Factorization: A non-negative factor model with optimal utilization of error estimates of data values, Environmetrics, 5, 111–126, https://doi.org/10.1002/env.3170050203, 1994. 
                    
                
                        
                        Petters, M. D. and Kreidenweis, S. M.: A single parameter representation of hygroscopic growth and cloud condensation nucleus activity, Atmos. Chem. Phys., 7, 1961–1971, https://doi.org/10.5194/acp-7-1961-2007, 2007. 
                    
                
                        
                        Polissar, A. V., Hopke, P. K., Malm, W. C., and Sisler, J. F.: Atmospheric Aerosol over Alaska: 2. Elemental Composition and Sources, J. Geophys. Res.-Atmos., 103, 19045–19057, https://doi.org/10.1029/98JD01212, 1998. 
                    
                
                        
                        Song, S., Nenes, A., Gao, M., Zhang, Y., Liu, P., Shao, J., Ye, D., Xu, W., Lei, L., Sun, Y., Liu, B., Wang, S., and McElroy, M. B.: Thermodynamic Modeling Suggests Declines in Water Uptake and Acidity of Inorganic Aerosols in Beijing Winter Haze Events during 2014/2015–2018/2019, Environ. Sci. Tech. Let., 6, 752–760, https://doi.org/10.1021/acs.estlett.9b00621, 2019. 
                    
                
                        
                        Sun, Y., Lei, L., Zhou, W., Chen, C., He, Y., Sun, J., Li, Z., Xu, W., Wang, Q., Ji, D., Fu, P., Wang, Z., and Worsnop, D.: A chemical cocktail during the COVID-19 outbreak in Beijing, China: insights from six-year aerosol particle composition measurements during the Chinese New Year holiday, Sci. Total Environ., 742, 140739, https://doi.org/10.1016/j.scitotenv.2020.140739, 2020. 
                    
                
                        
                        Topping, D. O., McFiggans, G. B., and Coe, H.: A curved multi-component aerosol hygroscopicity model framework: Part 1 – Inorganic compounds, Atmos. Chem. Phys., 5, 1205–1222, https://doi.org/10.5194/acp-5-1205-2005, 2005. 
                    
                
                        
                        Ulbrich, I. M., Canagaratna, M. R., Cubison, M. J., Zhang, Q., Ng, N. L., Aiken, A. C., and Jimenez, J. L.: Three-dimensional factorization of size-resolved organic aerosol mass spectra from Mexico City, Atmos. Meas. Tech., 5, 195–224, https://doi.org/10.5194/amt-5-195-2012, 2012. 
                    
                
                        
                        Wang, M., Zhang, Z., Yuan, Q., Li, X., Han, S., Lam, Y., Cui, L., Huang, Y., Cao, J., and Lee, S.-C.: Slower than expected reduction in annual PM2.5 in Xi'an revealed by machine learning-based meteorological normalization, Sci. Total Environ., 841, 156740, https://doi.org/10.1016/j.scitotenv.2022.156740, 2022. 
                    
                
                        
                        Wang, Y. H., Gao, W. K., Wang, S. A., Song, T., Gong, Z. Y., Ji, D. S., Wang, L. L., Liu, Z. R., Tang, G. Q., Huo, Y. F., Tian, S. L., Li, J. Y., Li, M. G., Yang, Y., Chu, B. W., Petäjä, T., Kerminen, V.-M., He, H., Hao, J. M., Kulmala, M., Wang, Y. S., and Zhang, Y. H.: Contrasting trends of PM2.5 and surface-ozone concentrations in China from 2013 to 2017, Natl. Sci. Rev., 7, 1331–1339, https://doi.org/10.1093/nsr/nwaa032, 2020. 
                    
                
                        
                        Wu, D., Zheng, H., Li, Q., Jin, L., Lyu, R., Ding, X., Huo, Y., Zhao, B., Jiang, J., and Chen, J.: Toxic potency-adjusted control of air pollution for solid fuel combustion, Nat. Energy, 7, 194–202, https://doi.org/10.1038/s41560-021-00951-1, 2022. 
                    
                
                        
                        Wu, Z., Wang, Y., Tan, T., Zhu, Y., Li, M., Shang, D., Wang, H., Lu, K., Guo, S., Zeng, L., and Zhang, Y.: Aerosol liquid water driven by anthropogenic inorganic salts: implying its key role in haze formation over the North China Plain, Environ. Sci. Tech. Let., 5, 160–166, https://doi.org/10.1021/acs.estlett.8b00021, 2018. 
                    
                
                        
                        Xie, F., Su, Y., Tian, Y., Shi, Y., Zhou, X., Wang, P., Yu, R., Wang, W., He, J., Xin, J., and Lü, C.: The shifting of secondary inorganic aerosol formation mechanisms during haze aggravation: the decisive role of aerosol liquid water, Atmos. Chem. Phys., 23, 2365–2378, https://doi.org/10.5194/acp-23-2365-2023, 2023. 
                    
                
                        
                        Xu, J., Ge, X., Zhang, X., Zhao, W., Zhang, R., and Zhang, Y.: COVID-19 impact on the concentration and composition of submicron particulate matter in a typical city of Northwest China, Geophys. Res. Lett., 47, e2020GL089035, https://doi.org/10.1029/2020GL089035, 2020. 
                    
                
                        
                        Xu, W., Sun, Y., Wang, Q., Zhao, J., Wang, J., Ge, X., Xie, C., Zhou, W., Du, W., Li, J., Fu, P., Wang, Z., Worsnop, D. R., and Coe, H.: Changes in aerosol chemistry from 2014 to 2016 in winter in Beijing: Insights from high-resolution aerosol mass spectrometry, J. Geophys. Res.-Atmos., 124, 1132–1147, https://doi.org/10.1029/2018JD029245, 2019. 
                    
                
                        
                        Xu, W., Chen, C., Qiu, Y., Xie, C., Chen, Y., Ma, N., Xu, W., Fu, P., Wang, Z., Pan, X., Zhu, J., Ng, N. L., and Sun, Y.: Size-resolved characterization of organic aerosol in the North China Plain: new insights from high resolution spectral analysis, Environ. Sci. Atmos., 1, 346–358, https://doi.org/10.1039/D1EA00025J, 2021. 
                    
                
                        
                        Zhang, J. K., Sun, Y., Liu, Z. R., Ji, D. S., Hu, B., Liu, Q., and Wang, Y. S.: Characterization of submicron aerosols during a month of serious pollution in Beijing, 2013, Atmos. Chem. Phys., 14, 2887–2903, https://doi.org/10.5194/acp-14-2887-2014, 2014. 
                    
                
                        
                        Zhang, Q., Zheng, Y., Tong, D., Shao, M., Wang, S., Zhang, Y., Xu, X., Wang, J., He, H., Liu, W., Ding, Y., Lei, Y., Li, J., Wang, Z., Zhang, X., Wang, Y., Cheng, J., Liu, Y., Shi, Q., Yan, L., Geng, G., Hong, C., Li, M., Liu, F., Zheng, B., Cao, J., Ding, A., Gao, J., Fu, Q., Huo, J., Liu, B., Liu, Z., Yang, F., He, K., and Hao, J.: Drivers of Improved PM2.5 Air Quality in China from 2013 to 2017, P. Natl. Acad. Sci. USA, 116, 24463–24469, https://doi.org/10.1073/pnas.1907956116, 2019. 
                    
                
                        
                        Zhang, R. Y., Wang, G. H., Guo, S., Zarnora, M. L., Ying, Q., Lin, Y., Wang, W. G., Hu, M., and Wang, Y.: Formation of Urban Fine Particulate Matter, Chem. Rev., 115, 3803–3855, https://doi.org/10.1021/acs.chemrev.5b00067, 2015. 
                    
                
                        
                        Zhang, Y., Vu, T. V., Sun, J., He, J., Shen, X., Lin, W., Zhang, X., Zhong, J., Gao, W., Wang, Y., Fu, T. M., Ma, Y., Li, W., and Shi, Z.: Significant Changes in Chemistry of Fine Particles in Wintertime Beijing from 2007 to 2017: Impact of Clean Air Actions, Environ. Sci. Technol., 54, 1344–1352, https://doi.org/10.1021/acs.est.9b04678, 2020. 
                    
                
                        
                        Zheng, B., Tong, D., Li, M., Liu, F., Hong, C., Geng, G., Li, H., Li, X., Peng, L., Qi, J., Yan, L., Zhang, Y., Zhao, H., Zheng, Y., He, K., and Zhang, Q.: Trends in China's anthropogenic emissions since 2010 as the consequence of clean air actions, Atmos. Chem. Phys., 18, 14095–14111, https://doi.org/10.5194/acp-18-14095-2018, 2018.  
                    
                
                        
                        Zheng, Y., Chen, Q., Cheng, X., Mohr, C., Cai, J., Huang, W., Shrivastava, M., Ye, P., Fu, P., Shi, X., Ge, Y., Liao, K., Miao, R., Qiu, X., Koenig, T. K., and Chen, S.: Precursors and Pathways Leading to Enhanced Secondary Organic Aerosol Formation during Severe Haze Episodes, Environ. Sci. Technol., 55, 15680–15693, https://doi.org/10.1021/acs.est.1c04255, 2021. 
                    
                
                        
                        Zhong, H., Huang, R.-J., Duan, J., Lin, C., Gu, Y., Wang, Y., Li, Y. J., Zheng, Y., Chen, Q., Chen, Y., Dai, W. T., Ni, H. Y., Cao, J. J., Worsnop, D. R., Xu, W., Ovadnevaite, J., Ceburnis, D., and O'Dowd, C. D.: Seasonal variations in the sources of organic aerosol in Xi'an, Northwest China: The importance of biomass burning and secondary formation, Sci. Total Environ., 737, 139666, https://doi.org/10.1016/j.scitotenv.2020.139666, 2020. 
                    
                
                        
                        Zhong, H., Huang, R.-J., Lin, C., Xu, W., Duan, J., Gu, Y., Huang, W., Ni, H., Zhu, C., You, Y., Wu, Y., Zhang, R., Ovadnevaite, J., Ceburnis, D., and O'Dowd, C. D.: Measurement report: On the contribution of long-distance transport to the secondary aerosol formation and aging, Atmos. Chem. Phys., 22, 9513–9524, https://doi.org/10.5194/acp-22-9513-2022, 2022. 
                    
                Short summary
                    The chemical composition of atmospheric particles has shown significant changes in recent years. We investigated the potential effects of changes in inorganics on aerosol water uptake and, thus, secondary organic aerosol formation in wintertime haze based on the size-resolved measurements of non-refractory fine particulate matter (NR-PM2.5) in Xi’an, northwestern China. We highlight the key role of aerosol water as a medium to link inorganics and organics in their multiphase processes.
                    The chemical composition of atmospheric particles has shown significant changes in recent years....
                    
                Altmetrics
                
                Final-revised paper
            
            
                    Preprint