Articles | Volume 23, issue 18
https://doi.org/10.5194/acp-23-10313-2023
© Author(s) 2023. 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-23-10313-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
15 Sep 2023
Research article |
| 15 Sep 2023
| 15 Sep 2023
Reduction in vehicular emissions attributable to the Covid-19 lockdown in Shanghai: insights from 5 years of monitoring-based machine learning
Meng Wang
Department of Civil and Environmental Engineering, The Hong Kong
Polytechnic University, Hung Hom, Hong Kong SAR, China
Yusen Duan
Shanghai Environmental Monitoring Center, Shanghai, China
Zhuozhi Zhang
Department of Civil and Environmental Engineering, The Hong Kong
Polytechnic University, Hung Hom, Hong Kong SAR, China
Qi Yuan
Department of Civil and Environmental Engineering, The Hong Kong
Polytechnic University, Hung Hom, Hong Kong SAR, China
Xinwei Li
Department of Civil and Environmental Engineering, The Hong Kong
Polytechnic University, Hung Hom, Hong Kong SAR, China
Shuwen Han
Department of Civil and Environmental Engineering, The Hong Kong
Polytechnic University, Hung Hom, Hong Kong SAR, China
Juntao Huo
Shanghai Environmental Monitoring Center, Shanghai, China
Jia Chen
Shanghai Environmental Monitoring Center, Shanghai, China
Yanfen Lin
Shanghai Environmental Monitoring Center, Shanghai, China
Shanghai Environmental Monitoring Center, Shanghai, China
Department of Civil and Environmental Engineering, The Hong Kong
Polytechnic University, Hung Hom, Hong Kong SAR, China
Junji Cao
State Key Laboratory of Loess and Quaternary Geology, Institute of
Earth Environment, Chinese Academy of Sciences, Xi'an 710061,
China
Laboratory for Middle Atmosphere and Global Environment
Observation, Institute of Atmospheric Physics, Chinese Academy
of Sciences,
Beijing 100029, China
Shun-cheng Lee
CORRESPONDING AUTHOR
Department of Civil and Environmental Engineering, The Hong Kong
Polytechnic University, Hung Hom, Hong Kong SAR, China
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Atmos. Chem. Phys., 23, 7057–7074, https://doi.org/10.5194/acp-23-7057-2023, https://doi.org/10.5194/acp-23-7057-2023, 2023
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Yizhen Wu, Juntao Huo, Gan Yang, Yuwei Wang, Lihong Wang, Shijian Wu, Lei Yao, Qingyan Fu, and Lin Wang
Atmos. Chem. Phys., 23, 2997–3014, https://doi.org/10.5194/acp-23-2997-2023, https://doi.org/10.5194/acp-23-2997-2023, 2023
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Yu Han, Tao Wang, Rui Li, Hongbo Fu, Yusen Duan, Song Gao, Liwu Zhang, and Jianmin Chen
Atmos. Chem. Phys., 23, 2877–2900, https://doi.org/10.5194/acp-23-2877-2023, https://doi.org/10.5194/acp-23-2877-2023, 2023
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Limited knowledge is available on volatile organic compound (VOC) multi-site research of different land-use types at city level. This study performed a concurrent multi-site observation campaign on the three typical land-use types of Shanghai, East China. The results showed that concentrations, sources and ozone and secondary organic aerosol formation potentials of VOCs varied with the land-use types.
Jie Tian, Qiyuan Wang, Yongyong Ma, Jin Wang, Yongming Han, and Junji Cao
Atmos. Chem. Phys., 23, 1879–1892, https://doi.org/10.5194/acp-23-1879-2023, https://doi.org/10.5194/acp-23-1879-2023, 2023
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Atmos. Chem. Phys., 23, 1329–1343, https://doi.org/10.5194/acp-23-1329-2023, https://doi.org/10.5194/acp-23-1329-2023, 2023
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The particle matter (PM2.5) at the top of the 632 m high Shanghai Tower was found to be higher than the surface from June to October due to unexpected larger PM2.5 levels during early to middle afternoon at Shanghai Tower. We suppose the significant chemical production of secondary species existed in the mid-upper planetary boundary layer. We found a high nitrate concentration at the tower site for both daytime and nighttime in winter, implying efficient gas-phase and heterogeneous formation.
Xiaofei Qin, Shengqian Zhou, Hao Li, Guochen Wang, Cheng Chen, Chengfeng Liu, Xiaohao Wang, Juntao Huo, Yanfen Lin, Jia Chen, Qingyan Fu, Yusen Duan, Kan Huang, and Congrui Deng
Atmos. Chem. Phys., 22, 15851–15865, https://doi.org/10.5194/acp-22-15851-2022, https://doi.org/10.5194/acp-22-15851-2022, 2022
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Using artificial neural network modeling and an explainable analysis approach, natural surface emissions (NSEs) were identified as a main driver of gaseous elemental mercury (GEM) variations during the COVID-19 lockdown. A sharp drop in GEM concentrations due to a significant reduction in anthropogenic emissions may disrupt the surface–air exchange balance of Hg, leading to increases in NSEs. This implies that NSEs may pose challenges to the future control of Hg pollution.
Yue Tan and Tao Wang
Atmos. Chem. Phys., 22, 14455–14466, https://doi.org/10.5194/acp-22-14455-2022, https://doi.org/10.5194/acp-22-14455-2022, 2022
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We present a timely analysis of the effects of the recent lockdown in Shanghai on ground-level ozone (O3). Despite a huge reduction in human activity, O3 concentrations frequently exceeded the O3 air quality standard during the 2-month lockdown, implying that future emission reductions similar to those that occurred during the lockdown will not be sufficient to eliminate O3 pollution in many urban areas without the imposition of additional VOC controls or substantial decreases in NOx emissions.
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
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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.
Huikun Liu, Qiyuan Wang, Suixin Liu, Bianhong Zhou, Yao Qu, Jie Tian, Ting Zhang, Yongming Han, and Junji Cao
Atmos. Chem. Phys., 22, 11739–11757, https://doi.org/10.5194/acp-22-11739-2022, https://doi.org/10.5194/acp-22-11739-2022, 2022
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Atmospheric motions play an important role in the mass concentration and the direct radiative effect (DRE) of black carbon (BC). The finding from this study elaborated the impacts of different scales of atmospheric motion on source-specific BC and its DREs, which revealed the nonlinear change between BC mass concentration and its DREs and emphasizes the importance of regionally transported BC for potential climatic effects.
Jie Tian, Qiyuan Wang, Huikun Liu, Yongyong Ma, Suixin Liu, Yong Zhang, Weikang Ran, Yongming Han, and Junji Cao
Atmos. Chem. Phys., 22, 8369–8384, https://doi.org/10.5194/acp-22-8369-2022, https://doi.org/10.5194/acp-22-8369-2022, 2022
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We investigated aerosol optical properties and the direct radiative effect (DRE) at an urban site in China before and during the COVID-19 lockdown. The total light extinction coefficient (bext) decreased under emission control measures; however, bext from biomass burning increased due to the undiminished need for residential cooking and heating. Biomass burning, rather than traffic-related emissions, became the largest positive effect contributor to aerosol DRE in the lockdown.
Han Zang, Yue Zhao, Juntao Huo, Qianbiao Zhao, Qingyan Fu, Yusen Duan, Jingyuan Shao, Cheng Huang, Jingyu An, Likun Xue, Ziyue Li, Chenxi Li, and Huayun Xiao
Atmos. Chem. Phys., 22, 4355–4374, https://doi.org/10.5194/acp-22-4355-2022, https://doi.org/10.5194/acp-22-4355-2022, 2022
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Particulate nitrate plays an important role in wintertime haze pollution in eastern China, yet quantitative constraints on detailed nitrate formation mechanisms remain limited. Here we quantified the contributions of the heterogeneous N2O5 hydrolysis (66 %) and gas-phase OH + NO2 reaction (32 %) to nitrate formation in this region and identified the atmospheric oxidation capacity (i.e., availability of O3 and OH radicals) as the driving factor of nitrate formation from both processes.
Yuting Zhang, Hang Liu, Shandong Lei, Wanyun Xu, Yu Tian, Weijie Yao, Xiaoyong Liu, Qi Liao, Jie Li, Chun Chen, Yele Sun, Pingqing Fu, Jinyuan Xin, Junji Cao, Xiaole Pan, and Zifa Wang
Atmos. Chem. Phys., 21, 17631–17648, https://doi.org/10.5194/acp-21-17631-2021, https://doi.org/10.5194/acp-21-17631-2021, 2021
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In this study, the authors used a single-particle soot photometer (SP2) to characterize the particle size, mixing state, and optical properties of black carbon aerosols in rural areas of the North China Plain in winter. Relatively warm and high-RH environments (RH > 50 %, −4° < T < 4 °) were more favorable to rBC aging than dry and cold environments (RH < 60 %, T < −8°). The paper emphasizes the importance of meteorological parameters in the mixing state of black carbon.
Men Xia, Xiang Peng, Weihao Wang, Chuan Yu, Zhe Wang, Yee Jun Tham, Jianmin Chen, Hui Chen, Yujing Mu, Chenglong Zhang, Pengfei Liu, Likun Xue, Xinfeng Wang, Jian Gao, Hong Li, and Tao Wang
Atmos. Chem. Phys., 21, 15985–16000, https://doi.org/10.5194/acp-21-15985-2021, https://doi.org/10.5194/acp-21-15985-2021, 2021
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ClNO2 is an important precursor of chlorine radical that affects photochemistry. However, its production and impact are not well understood. Our study presents field observations of ClNO2 at three sites in northern China. These observations provide new insights into nighttime processes that produce ClNO2 and the significant impact of ClNO2 on secondary pollutions during daytime. The results improve the understanding of photochemical pollution in the lower part of the atmosphere.
Thierno Doumbia, Claire Granier, Nellie Elguindi, Idir Bouarar, Sabine Darras, Guy Brasseur, Benjamin Gaubert, Yiming Liu, Xiaoqin Shi, Trissevgeni Stavrakou, Simone Tilmes, Forrest Lacey, Adrien Deroubaix, and Tao Wang
Earth Syst. Sci. Data, 13, 4191–4206, https://doi.org/10.5194/essd-13-4191-2021, https://doi.org/10.5194/essd-13-4191-2021, 2021
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Most countries around the world have implemented control measures to combat the spread of the COVID-19 pandemic, resulting in significant changes in economic and personal activities. We developed the CONFORM (COvid-19 adjustmeNt Factors fOR eMissions) dataset to account for changes in emissions during lockdowns. This dataset was created with the intention of being directly applicable to existing global and regional inventories used in chemical transport models.
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
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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.
Jianing Dai and Tao Wang
Atmos. Chem. Phys., 21, 8747–8759, https://doi.org/10.5194/acp-21-8747-2021, https://doi.org/10.5194/acp-21-8747-2021, 2021
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We used the WRF–Chem model with the latest HONO and ClNO2 processes to investigate their effects on the concentrations of ROx radicals, O3, and PM2.5 in Asia during summer. The results show that the ship-derived HONO and ClNO2 increased the ROx radical concentration by 2–3 times and subsequently increased the O3 and PM2.5 concentrations in marine areas. These findings indicate the importance of these nitrogen processes in the evaluation of the impact of ship emissions on air quality.
Kun Zhang, Ling Huang, Qing Li, Juntao Huo, Yusen Duan, Yuhang Wang, Elly Yaluk, Yangjun Wang, Qingyan Fu, and Li Li
Atmos. Chem. Phys., 21, 5905–5917, https://doi.org/10.5194/acp-21-5905-2021, https://doi.org/10.5194/acp-21-5905-2021, 2021
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Recently, high O3 concentrations were frequently observed in rural areas of the Yangtze River Delta (YRD) region under stagnant conditions. Using an online measurement and observation-based model, we investigated the budget of ROx radicals and the influence of isoprene chemistry on O3 formation. Our results underline that isoprene chemistry in the rural atmosphere becomes important with the participation of anthropogenic NOx.
Yuting Wang, Yong-Feng Ma, Domingo Muñoz-Esparza, Cathy W. Y. Li, Mary Barth, Tao Wang, and Guy P. Brasseur
Atmos. Chem. Phys., 21, 3531–3553, https://doi.org/10.5194/acp-21-3531-2021, https://doi.org/10.5194/acp-21-3531-2021, 2021
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Large-eddy simulations (LESs) were performed in the mountainous region of the island of Hong Kong to investigate the degree to which the rates of chemical reactions between two reactive species are reduced due to the segregation of species within the convective boundary layer. We show that the inhomogeneity in emissions plays an important role in the segregation effect. Topography also has a significant influence on the segregation locally.
Yujiao Zhu, Likun Xue, Jian Gao, Jianmin Chen, Hongyong Li, Yong Zhao, Zhaoxin Guo, Tianshu Chen, Liang Wen, Penggang Zheng, Ye Shan, Xinfeng Wang, Tao Wang, Xiaohong Yao, and Wenxing Wang
Atmos. Chem. Phys., 21, 1305–1323, https://doi.org/10.5194/acp-21-1305-2021, https://doi.org/10.5194/acp-21-1305-2021, 2021
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This work investigates the long-term changes in new particle formation (NPF) events under reduced SO2 emissions at the summit of Mt. Tai during seven campaigns from 2007 to 2018. We found the NPF intensity increased 2- to 3-fold in 2018 compared to 2007. In contrast, the probability of new particles growing to CCN size largely decreased. Changes to biogenic VOCs and anthropogenic emissions are proposed to explain the distinct NPF characteristics.
Rui Li, Qiongqiong Wang, Xiao He, Shuhui Zhu, Kun Zhang, Yusen Duan, Qingyan Fu, Liping Qiao, Yangjun Wang, Ling Huang, Li Li, and Jian Zhen Yu
Atmos. Chem. Phys., 20, 12047–12061, https://doi.org/10.5194/acp-20-12047-2020, https://doi.org/10.5194/acp-20-12047-2020, 2020
Zhenhao Ling, Qianqian Xie, Min Shao, Zhe Wang, Tao Wang, Hai Guo, and Xuemei Wang
Atmos. Chem. Phys., 20, 11451–11467, https://doi.org/10.5194/acp-20-11451-2020, https://doi.org/10.5194/acp-20-11451-2020, 2020
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The observation data from a receptor site in the Pearl River Delta region were analyzed by a photochemical box model with near-explicit chemical mechanisms (i.e., the Master Chemical Mechanism, MCM), improvements with reversible and irreversible heterogeneous processes of glyoxal and methylglyoxal, and the gas-particle partitioning of oxidation products in the present study.
Xiaofei Qin, Leiming Zhang, Guochen Wang, Xiaohao Wang, Qingyan Fu, Jian Xu, Hao Li, Jia Chen, Qianbiao Zhao, Yanfen Lin, Juntao Huo, Fengwen Wang, Kan Huang, and Congrui Deng
Atmos. Chem. Phys., 20, 10985–10996, https://doi.org/10.5194/acp-20-10985-2020, https://doi.org/10.5194/acp-20-10985-2020, 2020
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The uncertainties in mercury emissions are much larger from natural sources than anthropogenic sources. A method was developed to quantify the contributions of natural surface emissions to ambient GEM based on PMF modeling. The annual GEM concentration in eastern China showed a decreasing trend from 2015 to 2018, while the relative contribution of natural surface emissions increased significantly from 41 % in 2015 to 57 % in 2018, gradually surpassing those from anthropogenic sources.
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Short summary
Hourly elemental carbon (EC) and NOx were continuously measured for 5 years (2016–2020) at a sampling site near a highway in western Shanghai. We use a machine learning model to rebuild the measured EC and NOx, and a business-as-usual (BAU) scenario was assumed in 2020 and compared with the measured EC and NOx.
Hourly elemental carbon (EC) and NOx were continuously measured for 5 years (2016–2020) at a...
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