Articles | Volume 25, issue 22
https://doi.org/10.5194/acp-25-16679-2025
© Author(s) 2025. 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-25-16679-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Measurement report
| 
25 Nov 2025
Measurement report |
| 25 Nov 2025
| 25 Nov 2025
Measurement report: Anthropogenic activities reduction suppresses HONO formation: direct evidence for secondary pollution control
Mingzhu Zhai
State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
University of Chinese Academy of Sciences, Beijing 100049, China
Shengrui Tong
CORRESPONDING AUTHOR
State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
Wenqian Zhang
NEAC Key Laboratory of Ecology and Environment in Minority Areas, College of Life and Environmental Sciences, Minzu University of China, Beijing, China
Hailiang Zhang
State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
Xiaoqi Wang
Key Laboratory of Beijing on Regional Air Pollution Control, Faculty of Environment Science and Engineering, Beijing University of Technology, Beijing 100124, China
State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
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Rui Tan, Xinshi Ni, Zichao Wan, Xudong Tian, Jiasi Shen, Bingye Xu, Da Xu, Sihua Lu, Xin Li, and Song Guo
EGUsphere, https://doi.org/10.5194/egusphere-2026-6413, https://doi.org/10.5194/egusphere-2026-6413, 2026
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
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Ozone and the hydroxyl radical both oxidise monoterpenes emitted by vegetation, but their shares in the vapours that go on to form aerosol are hard to separate outdoors because the two oxidants rise and fall together. A month of continuous measurements at a coastal site in eastern China, analysed with an interpretable machine learning method, shows that ozone dominates and that its influence appears mainly above about 62 ppb of ozone.
Zhengliang Dong, Hongbin Jiang, Haichuan Wei, Wei Qin, Yukun Cao, Li Zhou, Dongyang Chen, Song Liu, Fumo Yang, Weigang Wang, and Maofa Ge
EGUsphere, https://doi.org/10.5194/egusphere-2026-5149, https://doi.org/10.5194/egusphere-2026-5149, 2026
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
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Understanding peroxyacetyl nitrate (PAN) drivers is crucial to mitigate photochemical smog. Using one-year observations and a box model–machine learning framework in a basin city, we show that PAN drivers shift from warm-season chemical recycling to winter meteorology. PA radical production surges by 77 % during O3 episodes. NOx shows opposing seasonal impacts, while VOC reduction enables coordinated PAN-O3 control. These findings highlight the need for seasonally tailored mitigation strategies.
Shengjin Xie, Xuelei Zhang, Aijun Xiu, Hong Qi, Shengrui Tong, Qianjie Chen, Chao Gao, Hongmei Zhao, Shichun Zhang, Stephen Dauda Yabo, Yiming Liu, Siting Li, and Mengduo Zhang
The Cryosphere, 20, 5435–5451, https://doi.org/10.5194/tc-20-5435-2026, https://doi.org/10.5194/tc-20-5435-2026, 2026
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This study examines how snow-covered surfaces affect air pollution in Northeast China. Using numerical simulations, we explore chlorine-related chemical reactions that generate reactive species, enhancing fine particles and ozone. Results show that snow-surface reactions drive nighttime pollutant accumulation and notably improve model performance, providing new insights into how snow and surface chemistry influence regional air quality.
Yongxin Yan, Junling Li, Yufei Song, Yushi Gong, Shudan Wei, Zhaolin Wang, Haijie Zhang, Yanqin Ren, Maofa Ge, and Hong Li
Atmos. Chem. Phys., 26, 6147–6163, https://doi.org/10.5194/acp-26-6147-2026, https://doi.org/10.5194/acp-26-6147-2026, 2026
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This work examines NH3 effects on photochemical oxidation of mixed anthropogenic and biogenic volatile organic compounds (VOC) under high-NOx conditions. NH3 promotes nucleation and accelerates secondary organic aerosol (SOA) formation. NH3 enhances carbonyls, strengthens SOA formation via acid-base and radical reactions, and suppresses highly oxygenated organic molecules. Results improve understanding of SOA formation in complex emissions, aiding air quality forecasting.
Meifang Chen, Shengrui Tong, Shanshan Yu, Xiaofan Lv, Yanyong Xu, Hailiang Zhang, and Maofa Ge
Atmos. Chem. Phys., 26, 2103–2116, https://doi.org/10.5194/acp-26-2103-2026, https://doi.org/10.5194/acp-26-2103-2026, 2026
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The critical role of Criegee intermediates (CIs) in the myrcene ozonolysis was elucidated through the combined approach of matrix isolation Fourier transform infrared spectroscopy and smog chamber experiments. Distinct mechanisms of different-sized CIs in secondary organic aerosol formation were proposed, and a synergistic effect between RO2 autoxidation and CIs oligomerization was identified. This study provided new insights into the ozonolysis process from the Criegee chemistry perspective.
Yi Liu, Xin Li, Ying Liu, Shuyu He, Yuqing Qiu, Mengdi Song, Jiarong Ye, Shengrong Lou, Sihua Lu, Limin Zeng, and Yuanhang Zhang
Atmos. Chem. Phys., 25, 15819–15834, https://doi.org/10.5194/acp-25-15819-2025, https://doi.org/10.5194/acp-25-15819-2025, 2025
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We developed a method for speciated and quantitative measurement of peroxy radicals formed during the breakdown of aromatic hydrocarbons. These measurements revealed missing reaction pathways in current chemical mechanisms. Our findings help improve predictions of air quality and deepen understanding of chemical processes in the atmosphere.
Liuwei Kong, Xin Li, Yu Wang, Sihua Lu, Ying Liu, Shengrong Lou, Wenxin Zhou, Xinping Yang, Yan Ding, Yi Liu, Mengdi Song, Shuyu He, Kai Wang, Feng Wang, Xiaocen Shi, Jian Wang, Yun Zou, Chaofan Lian, Hefan Liu, Miao Feng, Xiaoya Dou, Limin Zeng, and Yuanhang Zhang
Atmos. Chem. Phys., 25, 13311–13326, https://doi.org/10.5194/acp-25-13311-2025, https://doi.org/10.5194/acp-25-13311-2025, 2025
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Our research investigates the volatile organic compounds evaporative emission characteristics of China's typical representative vehicle regulatory standards. The emission factors, chemical composition characteristics and source profiles of volatile organic compounds were determined. The hydroxyl radical total reactivity and compositions of evaporative emissions were quantified, and identified key volatile organic compounds reactive species contributing to atmospheric photochemical processes.
Chunmeng Li, Xiaorui Chen, Haichao Wang, Tianyu Zhai, Xuefei Ma, Xinping Yang, Shiyi Chen, Min Zhou, Shengrong Lou, Xin Li, Limin Zeng, and Keding Lu
Atmos. Chem. Phys., 25, 3905–3918, https://doi.org/10.5194/acp-25-3905-2025, https://doi.org/10.5194/acp-25-3905-2025, 2025
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This study reports an observation of organic nitrate (including total peroxy nitrates and total alkyl nitrates) in Shanghai, China, during the summer of 2021, by homemade thermal dissociation cavity-enhanced absorption spectroscopy (TD-CEAS; Atmos. Meas. Tech., 14, 4033–4051, 2021). The distribution of organic nitrates and their effects on local ozone production are analyzed based on field observations in conjunction with model simulations.
Renzhi Hu, Guoxian Zhang, Haotian Cai, Jingyi Guo, Keding Lu, Xin Li, Shengrong Lou, Zhaofeng Tan, Changjin Hu, Pinhua Xie, and Wenqing Liu
Atmos. Chem. Phys., 25, 3011–3028, https://doi.org/10.5194/acp-25-3011-2025, https://doi.org/10.5194/acp-25-3011-2025, 2025
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A full suite of radical measurements (OH, HO2, RO2, and kOH) was established to accurately elucidate the limitations of oxidation in a chemically complex atmosphere. Sensitivity tests revealed that the incorporation of complex processes enabled a balance in both radical concentrations and coordinate ratios, effectively addressing the deficiency in the ozone generation mechanism. The full-chain radical detection bridged the gap between the photochemistry and the intensive oxidation level.
Junling Li, Chaofan Lian, Mingyuan Liu, Hao Zhang, Yongxin Yan, Yufei Song, Chun Chen, Jiaqi Wang, Haijie Zhang, Yanqin Ren, Yucong Guo, Weigang Wang, Yisheng Xu, Hong Li, Jian Gao, and Maofa Ge
Atmos. Chem. Phys., 25, 2551–2568, https://doi.org/10.5194/acp-25-2551-2025, https://doi.org/10.5194/acp-25-2551-2025, 2025
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As a key source of hydroxyl (OH) radical, nitrous acid (HONO) has attracted much attention for its important role in the atmospheric oxidant capacity (AOC) increase. In this study, we made a comparison of the ambient levels, variation patterns, sources, and formation pathway in the warm season on the basis of continuous intensive observations at an urban site of Beijing. This work highlights the importance of HONO for the AOC in the warm season.
Yuqing Qiu, Xin Li, Wenxuan Chai, Yi Liu, Mengdi Song, Xudong Tian, Qiaoli Zou, Wenjun Lou, Wangyao Zhang, Juan Li, and Yuanhang Zhang
Atmos. Chem. Phys., 25, 1749–1763, https://doi.org/10.5194/acp-25-1749-2025, https://doi.org/10.5194/acp-25-1749-2025, 2025
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The chemical reactions of ozone (O3) formation are related to meteorology and local emissions. Here, a random forest approach was used to eliminate the effects of meteorological factors (dispersion or transport) on O3 and its precursors. Variations in the sensitivity of O3 formation and the apportionment of emission sources were revealed after meteorological normalization. Our results suggest that meteorological variations should be considered when diagnosing O3 formation.
Mengdi Song, Shuyu He, Xin Li, Ying Liu, Shengrong Lou, Sihua Lu, Limin Zeng, and Yuanhang Zhang
Atmos. Meas. Tech., 17, 5113–5127, https://doi.org/10.5194/amt-17-5113-2024, https://doi.org/10.5194/amt-17-5113-2024, 2024
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We introduce detailed and improved quantitation and semi-quantitation methods of iodide-adduct time-of-flight chemical ionization mass spectrometry (I-CIMS) to measure toluene oxidation intermediates. We assess the experimental sensitivity of various functional group species and their binding energy with iodide ions in I-CIMS. A novel classification approach was introduced to significantly enhance the accuracy of semi-quantitative methods (improving R2 values from 0.52 to beyond 0.88).
Hao Yang, Lei Chen, Hong Liao, Jia Zhu, Wenjie Wang, and Xin Li
Atmos. Chem. Phys., 24, 4001–4015, https://doi.org/10.5194/acp-24-4001-2024, https://doi.org/10.5194/acp-24-4001-2024, 2024
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The present study quantifies the response of aerosol–radiation interaction (ARI) to anthropogenic emission reduction from 2013 to 2017, with the main focus on the contribution to changed O3 concentrations over eastern China both in summer and winter using the WRF-Chem model. The weakened ARI due to decreased anthropogenic emission aggravates the summer (winter) O3 pollution by +0.81 ppb (+0.63 ppb), averaged over eastern China.
Guoxian Zhang, Renzhi Hu, Pinhua Xie, Changjin Hu, Xiaoyan Liu, Liujun Zhong, Haotian Cai, Bo Zhu, Shiyong Xia, Xiaofeng Huang, Xin Li, and Wenqing Liu
Atmos. Chem. Phys., 24, 1825–1839, https://doi.org/10.5194/acp-24-1825-2024, https://doi.org/10.5194/acp-24-1825-2024, 2024
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Comprehensive observation of HOx radicals was conducted at a coastal site in the Pearl River Delta. Radical chemistry was influenced by different air masses in a time-dependent way. Land mass promotes a more active photochemical process, with daily averages of 7.1 × 106 and 5.2 × 108 cm−3 for OH and HO2 respectively. The rapid oxidation process was accompanied by a higher diurnal HONO concentration, which influences the ozone-sensitive system and eventually magnifies the background ozone.
Chunxiang Ye, Shuzheng Guo, Weili Lin, Fangjie Tian, Jianshu Wang, Chong Zhang, Suzhen Chi, Yi Chen, Yingjie Zhang, Limin Zeng, Xin Li, Duo Bu, Jiacheng Zhou, and Weixiong Zhao
Atmos. Chem. Phys., 23, 10383–10397, https://doi.org/10.5194/acp-23-10383-2023, https://doi.org/10.5194/acp-23-10383-2023, 2023
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Online volatile organic compound (VOC) measurements by gas chromatography–mass spectrometry, with other O3 precursors, were used to identify key VOC and other key sources in Lhasa. Total VOCs (TVOCs), alkanes, and aromatics are half as abundant as in Beijing. Oxygenated VOCs (OVOCs) consist of 52 % of the TVOCs. Alkenes and OVOCs account for 80 % of the ozone formation potential. Aromatics dominate secondary organic aerosol potential. Positive matrix factorization decomposed residential sources.
Hejun Hu, Haichao Wang, Keding Lu, Jie Wang, Zelong Zheng, Xuezhen Xu, Tianyu Zhai, Xiaorui Chen, Xiao Lu, Wenxing Fu, Xin Li, Limin Zeng, Min Hu, Yuanhang Zhang, and Shaojia Fan
Atmos. Chem. Phys., 23, 8211–8223, https://doi.org/10.5194/acp-23-8211-2023, https://doi.org/10.5194/acp-23-8211-2023, 2023
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Nitrate radical chemistry is critical to the degradation of volatile organic compounds (VOCs) and secondary organic aerosol formation. This work investigated the level, seasonal variation, and trend of nitrate radical reactivity towards volatile organic compounds (kNO3) in Beijing. We show the key role of isoprene and styrene in regulating seasonal variation in kNO3 and rebuild a long-term record of kNO3 based on the reported VOC measurements.
Suding Yang, Xin Li, Limin Zeng, Xuena Yu, Ying Liu, Sihua Lu, Xiaofeng Huang, Dongmei Zhang, Haibin Xu, Shuchen Lin, Hefan Liu, Miao Feng, Danlin Song, Qinwen Tan, Jinhui Cui, Lifan Wang, Ying Chen, Wenjie Wang, Haijiong Sun, Mengdi Song, Liuwei Kong, Yi Liu, Linhui Wei, Xianwu Zhu, and Yuanhang Zhang
Atmos. Meas. Tech., 16, 501–512, https://doi.org/10.5194/amt-16-501-2023, https://doi.org/10.5194/amt-16-501-2023, 2023
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Vertical observation of volatile organic compounds (VOCs) is essential to study the spatial distribution and evolution patterns of VOCs in the planetary boundary layer (PBL). This paper describes multi-channel whole-air sampling equipment onboard an unmanned aerial vehicle (UAV) for near-continuous VOC vertical observation. Vertical profiles of VOCs and trace gases during the evolution of the PBL in south-western China have been successfully obtained by deploying the newly developed UAV system.
Xinping Yang, Keding Lu, Xuefei Ma, Yue Gao, Zhaofeng Tan, Haichao Wang, Xiaorui Chen, Xin Li, Xiaofeng Huang, Lingyan He, Mengxue Tang, Bo Zhu, Shiyi Chen, Huabin Dong, Limin Zeng, and Yuanhang Zhang
Atmos. Chem. Phys., 22, 12525–12542, https://doi.org/10.5194/acp-22-12525-2022, https://doi.org/10.5194/acp-22-12525-2022, 2022
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We present the OH and HO2 radical observations at the Shenzhen site (Pearl River Delta, China) in the autumn of 2018. The diurnal maxima were 4.5 × 106 cm−3 for OH and 4.2 × 108 cm−3 for HO2 (including an estimated interference of 23 %–28 % from RO2 radicals during the daytime). The OH underestimation was identified again, and it was attributable to the missing OH sources. HO2 heterogeneous uptake, ROx sources and sinks, and the atmospheric oxidation capacity were evaluated as well.
Junling Li, Kun Li, Hao Zhang, Xin Zhang, Yuanyuan Ji, Wanghui Chu, Yuxue Kong, Yangxi Chu, Yanqin Ren, Yujie Zhang, Haijie Zhang, Rui Gao, Zhenhai Wu, Fang Bi, Xuan Chen, Xuezhong Wang, Weigang Wang, Hong Li, and Maofa Ge
Atmos. Chem. Phys., 22, 10489–10504, https://doi.org/10.5194/acp-22-10489-2022, https://doi.org/10.5194/acp-22-10489-2022, 2022
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Ozone formation is enhanced by higher OH concentration and higher temperature but is influenced little by SO2. SO2 can largely enhance the particle formation. Organo-sulfates and organo-nitrates are detected in the formed particles, and the presence of SO2 can promote the formation of organo-sulfates. The results provide a scientific basis for systematically evaluating the effects of SO2, OH concentration, and temperature on the oxidation of mixed organic gases in the atmosphere.
Wenjie Wang, David D. Parrish, Siwen Wang, Fengxia Bao, Ruijing Ni, Xin Li, Suding Yang, Hongli Wang, Yafang Cheng, and Hang Su
Atmos. Chem. Phys., 22, 8935–8949, https://doi.org/10.5194/acp-22-8935-2022, https://doi.org/10.5194/acp-22-8935-2022, 2022
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Tropospheric ozone is an air pollutant that is detrimental to human health, vegetation and ecosystem productivity. A comprehensive characterisation of the spatial and temporal distribution of tropospheric ozone is critical to our understanding of these issues. Here we summarise this distribution over China from the available observational records to the extent possible. This study provides insights into efficient future ozone control strategies in China.
Jacky Yat Sing Pang, Anna Novelli, Martin Kaminski, Ismail-Hakki Acir, Birger Bohn, Philip T. M. Carlsson, Changmin Cho, Hans-Peter Dorn, Andreas Hofzumahaus, Xin Li, Anna Lutz, Sascha Nehr, David Reimer, Franz Rohrer, Ralf Tillmann, Robert Wegener, Astrid Kiendler-Scharr, Andreas Wahner, and Hendrik Fuchs
Atmos. Chem. Phys., 22, 8497–8527, https://doi.org/10.5194/acp-22-8497-2022, https://doi.org/10.5194/acp-22-8497-2022, 2022
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This study investigates the radical chemical budget during the limonene oxidation at different atmospheric-relevant NO concentrations in chamber experiments under atmospheric conditions. It is found that the model–measurement discrepancies of HO2 and RO2 are very large at low NO concentrations that are typical for forested environments. Possible additional processes impacting HO2 and RO2 concentrations are discussed.
Reza Bashiri Khuzestani, Keren Liao, Ying Liu, Ruqian Miao, Yan Zheng, Xi Cheng, Tianjiao Jia, Xin Li, Shiyi Chen, Guancong Huang, and Qi Chen
Atmos. Chem. Phys., 22, 7389–7404, https://doi.org/10.5194/acp-22-7389-2022, https://doi.org/10.5194/acp-22-7389-2022, 2022
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This work characterized the spatial variabilities of air pollutants in a megacity by advanced mobile measurements. The results show a large spatial heterogeneity in the distributions of PM2.5 composition and volatile organic compounds under non-haze conditions, and relatively uniform spatial distributions under haze conditions that may indicate a chemical homogeneity on an intracity scale. The findings improve our understanding of urban air pollution.
Xuefei Ma, Zhaofeng Tan, Keding Lu, Xinping Yang, Xiaorui Chen, Haichao Wang, Shiyi Chen, Xin Fang, Shule Li, Xin Li, Jingwei Liu, Ying Liu, Shengrong Lou, Wanyi Qiu, Hongli Wang, Limin Zeng, and Yuanhang Zhang
Atmos. Chem. Phys., 22, 7005–7028, https://doi.org/10.5194/acp-22-7005-2022, https://doi.org/10.5194/acp-22-7005-2022, 2022
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This paper presents the first OH and HO2 radical observations made in the Yangtze River Delta in China, and strong oxidation capacity is discovered based on direct measurements. The impacts of new OH regeneration mechanisms, monoterpene oxidation, and HO2 uptake processes are examined and discussed. The sources and the factors to sustain such strong oxidation are the key to understanding the ozone pollution formed in this area.
Hao Yang, Lei Chen, Hong Liao, Jia Zhu, Wenjie Wang, and Xin Li
Atmos. Chem. Phys., 22, 4101–4116, https://doi.org/10.5194/acp-22-4101-2022, https://doi.org/10.5194/acp-22-4101-2022, 2022
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Aerosols can influence O3 through aerosol–radiation interactions, including aerosol–photolysis interaction (API) and aerosol–radiation feedback (ARF). The weakened photolysis rates and changed meteorological conditions reduce surface-layer O3 concentrations by up to 9.3–11.4 ppb, with API and ARF contributing 74.6 %–90.0 % and 10.0 %–25.4 % of the O3 decrease in three episodes, respectively, which indicates that API is the dominant way for O3 reduction related to aerosol–radiation interactions.
Jingwei Zhang, Chaofan Lian, Weigang Wang, Maofa Ge, Yitian Guo, Haiyan Ran, Yusheng Zhang, Feixue Zheng, Xiaolong Fan, Chao Yan, Kaspar R. Daellenbach, Yongchun Liu, Markku Kulmala, and Junling An
Atmos. Chem. Phys., 22, 3275–3302, https://doi.org/10.5194/acp-22-3275-2022, https://doi.org/10.5194/acp-22-3275-2022, 2022
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This study added six potential HONO sources to the WRF-Chem model, evaluated their impact on HONO and O3 concentrations, including surface and vertical concentrations. The simulations extend our knowledge on atmospheric HONO sources, especially for nitrate photolysis. The study also explains the HONO difference in O3 formation on clean and hazy days, and reveals key potential HONO sources to O3 enhancements in haze-aggravating processes with a co-occurrence of high PM2.5 and O3 concentrations.
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Short summary
To explore how anthropogenic activities affect HONO formation, we conducted comprehensive observations in Beijing. During clean periods with a 53 % drop in Traffic Performance Index, HONO, CO, and NO2 levels decreased by 2–3 times compared to polluted periods. Emission reduction simulations showed that a 50 % NOx reduction could lower HONO by up to 46.3 %, indicating that reducing anthropogenic activities significantly suppresses HONO formation and provides direct evidence for pollution control.
To explore how anthropogenic activities affect HONO formation, we conducted comprehensive...
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