Significantly underestimated traffic-related ammonia emissions in Chinese megacities: Evidence from satellite observations during COVID-19 lockdowns

作     者：Chen, Peilin Wang, Qin'geng Shao, Min Liu, Rui 

作者机构：State Key Laboratory of Pollution Control and Resources Reuse School of the Environment Nanjing University Nanjing210023 China Collaborative Innovation Center of Atmospheric Environment and Equipment Technology Nanjing University of Information Science & Technology Nanjing210044 China School of the Environment Nanjing Normal University Nanjing210046 China 

出 版 物：《Chemosphere》 (Chemosphere)

年 卷 期：2024年第361卷

页      面：142497页

核心收录：

学科分类：0830[工学-环境科学与工程（可授工学、理学、农学学位）] 1004[医学-公共卫生与预防医学(可授医学、理学学位)] 1002[医学-临床医学] 1001[医学-基础医学(可授医学、理学学位)] 0817[工学-化学工程与技术] 08[工学] 0703[理学-化学] 

基　　金：This research has been supported by the National Key Research and Development Program of China (2016YFC0208504).This work was supported by the National Key Research and Development Program of China (2016YFC0208504). The authors acknowledge the AERIS data infrastructure for providing access to the IASI data in this study  ULB-LATMOS for the development of the retrieval algorithms (available at https://iasi.aeris-data.fr/). The authors acknowledge Nikolaos Evangeliou and other CrIS-related researchers for providing access to the data of global NH3 residence time. The physics-based oversampling source code is available online (https://github.com/Kang-Sun-CfA/Oversampling_matlab/blob/master/popy.py).This work was supported by the National Key Research and Development Program of China (2016YFC0208504). The authors acknowledge the AERIS data infrastructure for providing access to the IASI data in this study  ULB-LATMOS for the development of the retrieval algorithms (available at https://iasi.aeris-data.fr/ ). The authors acknowledge Nikolaos Evangeliou and other CrIS-related researchers for providing access to the data of global NH 3 residence time. The physics-based oversampling source code is available online ( https://github.com/Kang-Sun-CfA/Oversampling_matlab/blob/master/popy.py ) 

主　　题：COVID 19 

摘      要：Ammonia (NH3) plays an important role in the formation of atmospheric particulate matter, but the contribution of traffic-related emissions remains unclear, particularly in megacities with a large number of vehicles. Taking the opportunity of the stringent COVID-19 lockdowns implemented in Beijing and Shanghai in 2022, this study aims to estimate the traffic-related NH3 emissions in these two megacities based on satellite observations. Differences between urban and suburban areas during the lockdown and non-lockdown periods are compared. It was found that despite different dominating sources, the overall NH3 concentrations in urban and suburban areas were at a similar level, and the lockdown resulted in a more prominent decrease in urban areas, where traffic activities were most heavily affected. The traffic-related contribution to the total emission was estimated to be ∼30% in megacities, and ∼40% in urban areas, which are about 2–10 times higher than that in previous studies. The findings indicate that the traffic-related NH3 emissions have been significantly underestimated in previous studies and may play a more critical role in the formation of air pollution in megacities, especially in winter, when agricultural emissions are relatively low. This study highlights the importance of traffic-related NH3 emissions in Chinese megacities and the need to reassess the emissions and their impacts on air quality. © 2024 Elsevier Ltd