News Item
Chemistry, Multidisciplinary
Jian Zhen Yu
Summary: Atmospheric chemists found through kinetic measurements that nitrogen dioxide plays a significant role in the formation of sulfate during wintertime aerosol pollution events by reacting with dissolved SO2 at the interface of atmospheric relevant aerosol particles.
Article
Environmental Sciences
Zeeshan Javed, Aimon Tanvir, Muhammad Bilal, Wenjing Su, Congzi Xia, Abdul Rehman, Yuanyuan Zhang, Osama Sandhu, Chengzhi Xing, Xiangguang Ji, Mingjie Xie, Cheng Liu, Yuhang Wang
Summary: The study compared different retrieval settings for formaldehyde and sulfur dioxide under various weather conditions, finding that specific wavelength windows and polynomial orders led to significantly reduced fitting errors and improved accuracy of vertical column densities. Additionally, the observed vertical column densities of HCHO and SO2 were significantly lower on foggy days compared to clear days, indicating reduced chemical production of HCHO and aqueous phase oxidation of SO2 in fog droplets.
Article
Environmental Sciences
Shenbo Wang, Lingling Wang, Nan Wang, Shuangliang Ma, Fangcheng Su, Ruiqin Zhang
Summary: The size distribution and formation of secondary inorganic aerosol are key factors affecting the increase of PM2.5 concentration. Local processes were mainly influenced by local pollutant sources, while transport processes were affected by air mass transport. Different processes exhibited different particle size ranges and contributions to PM2.5 concentration growth.
Article
Chemistry, Multidisciplinary
Yuan Cheng, Xu-bing Cao, Jiu-meng Liu, Shengqiang Zhu, Siyu Wang, Qin-qin Yu, Hongliang Zhang, Qiang Zhang, Ke-bin He
Summary: This study tested a revised model using data from primary and secondary aerosol components measured in Harbin during the winter of 2019-2020. The results showed discrepancies between observed and simulated sulfate and secondary-organic-carbon concentrations under humid conditions, suggesting improper simulation of heterogeneous reactions. This suggests that previous modeling has exaggerated the role of sulfate in haze formation over Chinese megacities.
ENVIRONMENTAL CHEMISTRY LETTERS
(2022)
Review
Environmental Sciences
Qingxin Ma, Chunyan Zhang, Chang Liu, Guangzhi He, Peng Zhang, Hao Li, Biwu Chu, Hong He
Summary: The oxidation of sulfur dioxide (SO2) to sulfate in the atmosphere is important but controversial. Heterogeneous oxidation process on particle surfaces is considered an important missing mechanism in current models. This review summarizes the fundamental understanding of the heterogeneous reactions of SO2 on solid particles and discusses the factors affecting these reactions, as well as providing recommendations for future research.
CRITICAL REVIEWS IN ENVIRONMENTAL SCIENCE AND TECHNOLOGY
(2023)
Article
Meteorology & Atmospheric Sciences
Xiaokun Han, Yunchao Lang, Qingjun Guo, Xiaodong Li, Hu Ding, Siliang Li
Summary: This study investigates the mechanism of sulfate formation in PM2.5 samples collected in Tianjin, China using sulfur isotopic compositions and a model. The results show that there is a seasonal variation in sulfur isotopic fractionation values, with lower values in summer and higher values in winter. Additionally, the study finds that the relative contribution of the H2O2 pathway to sulfate formation is higher during the first stage of haze events.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2022)
Article
Environmental Sciences
Zehua Wang, Chenxi Zhang, Guochun Lv, Xiaomin Sun
Summary: This study investigated the reaction mechanism of SO2 and NO2 and the role of intermediate N2O4 using density-functional theory (DFT). It also analyzed the impact of different atmospheric components on the conversion of SO2 and NO2 to sulfate. The study found that NH3, H2O, and SO42- on the particulate surface can effectively reduce the activation energy of oxidation step, providing insight into the potential impact of atmospheric constituents on sulfate formation.
ATMOSPHERIC ENVIRONMENT
(2021)
Article
Environmental Sciences
Yang Yue, Jingru Cheng, Kang Soo Lee, Roman Stocker, Xu He, Maosheng Yao, Jing Wang
Summary: This study investigated the formation mechanism and influencing factors of sulfate in fine particles during haze episodes in different city environments through experiments and collected samples. The results revealed that relative humidity significantly affects the formation of new CaSO4.2H2O crystals.
ATMOSPHERIC ENVIRONMENT
(2022)
Article
Meteorology & Atmospheric Sciences
Xiaoping Tu, Risheng Yao, Lijun Hu, Difeng Xu, Hao Yang
Summary: A coastal fog patch near Zhejiang Province, China, on 1 April 2021 was investigated using various observation techniques and model simulations. The fog episode displayed macro-microphysical characteristics through five stages, including formation, burst, and dissipation. Moisture convergence associated with sea breeze played a crucial role in fog formation, along with weak ascent and low cloud formation. The collision-coalescence process intensified during the burst stage, and the top-cooling entrainment was the main reason for fog dissipation.
ATMOSPHERIC RESEARCH
(2023)
Article
Multidisciplinary Sciences
Shohei Hattori, Yoshinori Iizuka, Becky Alexander, Sakiko Ishino, Koji Fujita, Shuting Zhai, Tomas Sherwen, Naga Oshima, Ryu Uemura, Akinori Yamada, Nozomi Suzuki, Sumito Matoba, Asuka Tsuruta, Joel Savarino, Naohiro Yoshida
Summary: Since the 1980s, there has been a slower reduction in atmospheric sulfate compared to dramatic decreases in sulfur dioxide emissions. However, recent observations from a Greenland ice core show an increase in the oxygen isotopic composition of sulfate, indicating that acidity-dependent in-cloud oxidation by ozone has played a larger role in sulfate production since the 1960s. Global chemical transport models confirm an increase in conversion efficiency from SO2 to sulfate in Eastern North America and Western Europe, suggesting a continuing feedback mechanism that may hinder future air quality improvements.
Article
Environmental Sciences
Jinjin Sun, Momei Qin, Xiaodong Xie, Wenxing Fu, Yang Qin, Li Sheng, Lin Li, Jingyi Li, Ishaq Dimeji Sulaymon, Lei Jiang, Lin Huang, Xingna Yu, Jianlin Hu
Summary: This study utilized the CMAQ model to investigate the impact of regional transport, physical processes, and formation pathways on NO3- and total nitrate production in the Yangtze River Delta region in 2017. Findings show that NO3-/PM2.5 and NO3-/TNO3 levels are highest in winter, influenced primarily by aerosol processes and various formation pathways.
ATMOSPHERIC CHEMISTRY AND PHYSICS
(2022)
Article
Chemistry, Physical
Jongsik Kim, Dong Ho Kim, Jinseon Park, Keunhong Jeong, Heon Phil Ha
Summary: This study investigates the catalytic significance of SOA2- species in NH3-assisted selective NOx reduction and ammonium sulfate/absorbent poison degradation. The results show that mono-dentate and bi-dentate SOA2- species play crucial roles in directing the reaction pathways and improving the surface redox trait, thus promoting the low-temperature SCR performance and stability under different feed gas streams.
Article
Geosciences, Multidisciplinary
Xiang Ding, Qing Li, Di Wu, Xiaoyan Wang, Mei Li, Tao Wang, Lin Wang, Jianmin Chen
Summary: Observations showed that sulfate production in stack plumes equipped with wet desulfurization systems was previously underestimated, partially explaining the missing sulfate in most particle pollution episodes. Policymakers are suggested to target particulate emissions in order to reduce sulfate emissions for further air quality improvement.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Engineering, Environmental
Mei-Yi Fan, Yihang Hong, Yan-Lin Zhang, Tong Sha, Yu-Chi Lin, Fang Cao, Hai Guo
Summary: China's nitrogen oxide (NOx) emissions have significantly changed, but nonfossil fuel NOx emissions in urban areas are not well controlled. This results in a substantial underestimation of their importance compared to known fossil fuel NOx emissions. Using machine learning, we developed an approach that accurately generates a long time series of the nitrogen isotopic composition of atmospheric nitrate. The results showed a decrease in nitrate isotopic composition in Chinese megacities, indicating an enhanced contribution of nonfossil fuel NOx emissions and a transformation of China's energy structure.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Engineering, Environmental
Qi Ying, Jie Zhang, Hongliang Zhang, Jianlin Hu, Michael J. Kleeman
Summary: The modified CMAQ model was used to study the evolution of atmospheric age distributions of primary and secondary aerosols in China during severe winter pollution episodes. The results showed that increases in aerosol concentrations were associated with increases in atmospheric age, with sulfate exhibiting a broad spatial distribution of aged particles and nitrate and ammonium ions having lower concentrations and limited spatial distributions. The model's potential applications include evaluating meteorological impacts on air quality and developing emission control strategies.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2021)
Article
Environmental Sciences
Cui Guo, Ly-Yun Chang, Yacong Bo, Changqing Lin, Alexis K. H. Lau, Tony Tam, Xiang Qian Lao
Summary: This study investigated the association between life-course exposure to PM2.5 and incident hypertension in adulthood. The results showed that for every 10µg/m3 increase in PM2.5, the overall risk of adulthood hypertension increased by 40%. The health effects of PM2.5 exposure at different life stages on incident hypertension were generally independent of each other. The study suggests that life-course control of air pollution exposure should be implemented to alleviate the burden of adulthood hypertension.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2023)
Article
Environmental Sciences
Tao Li, Hanzhe Chen, Jimmy C. H. Fung, Damgy H. L. Chan, Alfred L. C. Yu, Kenneth K. M. Leung, Jian Zhen Yu
Summary: Urban fires release large amounts of manmade structures and synthetic materials, but real-world chemical composition data are rarely available. Monitoring of trace elements in PM2.5 in Hong Kong captured sharp spikes of bromine, chlorine, lead, zinc, and copper during fires, with concentrations 10-6000 times higher than pre-fire periods. These elements showed decreased concentrations with distance from the fire location but relatively constant concentration ratios. This study provides evidence of co-emissions of bromine and certain metals from urban fires and highlights their potential impacts on human health and atmospheric oxidizing capacity.
ATMOSPHERIC ENVIRONMENT
(2023)
Article
Construction & Building Technology
Lu Li, Yingdong He, Hui Zhang, Jimmy C. H. Fung, Alexis K. H. Lau
Summary: This paper describes the development and application of a multi-objective AI algorithm for practical environmental control, aiming to optimize indoor air quality, thermal comfort levels, and energy efficiency in buildings.
BUILDING AND ENVIRONMENT
(2023)
Article
Engineering, Environmental
Tao Li, Huiting Mao, Zhe Wang, Jian Zhen Yu, Shuwen Li, Xiaoling Nie, Hartmut Herrmann, Yan Wang
Summary: In a high-altitude coastal area in Hong Kong, the concentration of total gaseous mercury (TGM) was monitored and it was found that TGM peaks sharply during cold front passages due to Asian pollution outflow. Unlike other air pollutants, TGM exhibits a distinct diurnal variation with a midday minimum. After sunrise, four cases of rapid TGM depletion were observed, accompanied by an increase in other pollutants. These findings suggest significant effects of the interaction between anthropogenic pollution and marine halogen chemistry on atmospheric Hg cycling in coastal areas.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Engineering, Environmental
Kezheng Liao, Qiongqiong Wang, Shan Wang, Jian Zhen Yu
Summary: In this study, a novel Bayesian inference (BI) approach was used to accurately quantify primary organic carbon (POC) and secondary organic carbon (SOC) in fine particulate matter using only major component measurement data. The BI models showed significant advantages over conventional methods in estimating POC and SOC amounts. The use of sulfate as the SOC tracer in the BI model yielded the best model performance.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Environmental Sciences
Wenwei Che, Yumiao Zhang, Changqing Lin, Yik Him Fung, Jimmy C. H. Fung, Alexis K. H. Lau
Summary: Traditional air quality data with low spatial resolution cannot accurately capture the detailed air pollution exposure in complex urban areas. This study developed an ultra-fine resolution modeling system using big data fusion technology to provide street-level air quality data. The findings revealed sharp fine-scale variabilities in air pollution within individual city blocks. The study also highlighted the environmental inequities in population exposure to air pollutants caused by unfavorable city planning.
JOURNAL OF ENVIRONMENTAL SCIENCES
(2023)
Article
Meteorology & Atmospheric Sciences
Yueya Wang, Zijing Zhang, Wing Sze Chow, Zhe Wang, Jian Zhen Yu, Jimmy Chi-Hung Fung, Xiaoming Shi
Summary: The variation of aerosol concentrations has a significant impact on the rainfall pattern and intensity of South China's severe coastal convective precipitation. Changes in aerosol concentration affect cloud processes, such as cloud water number concentration, droplet size, and ice concentration, which in turn affect the intensity and duration of precipitation. The study highlights the importance of considering aerosol uncertainties in convective precipitation forecasting.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2023)
Article
Meteorology & Atmospheric Sciences
Kezheng Liao, Jie Zhang, Yiang Chen, Xingcheng Lu, Jimmy C. H. Fung, Qi Ying, Jian Zhen Yu
Summary: An observation-constrained hybrid model was developed to determine the source contributions of trace metals in PM2.5 in the Pearl River Delta region. The model achieved accurate predictions and provided valuable information for assessing the epidemiological impacts of trace metals and formulating effective control measures.
NPJ CLIMATE AND ATMOSPHERIC SCIENCE
(2023)
Article
Environmental Sciences
Changqing Lin, Jimmy C. H. Fung, Chao Ren, Edward Y. Y. Ng, Yuguo Li, Yueyang He, Kenneth K. M. Leung, Zhi Ning, Alexis K. H. Lau
Summary: This study uses a Light Detection and Ranging (LiDAR) system to measure wind profiles in an urban site in Hong Kong, and investigates the characteristics of ozone transport in the planetary boundary layer (PBL). The study finds that during ozone pollution episodes, there is increased regional transport from the Greater Bay Area (GBA), resulting in a predominant westerly component in the ozone flux. Additionally, clockwise veering winds are observed from the ground to the top of the PBL.
ATMOSPHERIC ENVIRONMENT
(2023)
Article
Chemistry, Medicinal
Wanlin Guo, Jian Zhen Yu, Wan Chan
Summary: Exposure to environmental tobacco smoke (ETS) significantly increases the risk of developing many human diseases, including lung cancer, and the most common method for assessing personal exposure to ETS is by sampling sidestream smoke. However, this method may not truly represent the ETS in the ambient environment. In this study, a new air sampling method involving breathing through a face mask was developed to simultaneously determine personal exposure to ETS-borne compounds, providing a convenient and sensitive way to assess the health impacts of ETS exposure.
CHEMICAL RESEARCH IN TOXICOLOGY
(2023)
Article
Engineering, Environmental
Yujue Wang, Yanjing Zhang, Wenshuai Li, Guanru Wu, Yuxuan Qi, Shubin Li, Wenqing Zhu, Jian Zhen Yu, Xu Yu, Hong-Hai Zhang, Jun Sun, Wencai Wang, Lifang Sheng, Xiaohong Yao, Huiwang Gao, Cheng Huang, Yingge Ma, Yang Zhou
Summary: Shipboard atmospheric observations in the Yellow Sea and Bohai Sea reveal the abundance and formation of organosulfates (OSs) in marine organic aerosols. The quantified OSs and NOSs account for a certain percentage of marine organic aerosols and non-sea-salt sulfate. The abundance of isoprene-related OSs is influenced by marine phytoplankton biomass and sea surface temperature.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Engineering, Environmental
Donger Lai, Yee Ka Wong, Rongshuang Xu, Sinan Xing, Sze In Madeleine Ng, Lin Kong, Jian Zhen Yu, Dan Dan Huang, Man Nin Chan
Summary: In this study, the heterogeneous OH oxidation of HMS was investigated. The results showed that the oxidation of HMS by OH can proceed efficiently, resulting in the formation of sulfate and peroxydisulfate, indicating a significant conversion of organic sulfur to inorganic sulfur.
ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS
(2023)
Article
Meteorology & Atmospheric Sciences
Xu Yu, Min Zhou, Jinjian Li, Liping Qiao, Shengrong Lou, Wenye Han, Zijing Zhang, Cheng Huang, Jian Zhen Yu
Summary: This study presents the first online measurements of organic nitrogen (ON) in PM2.5 in urban Shanghai, using a newly developed aerosol nitrogen analyzer. The results show that ON accounted for an average of 25% of total aerosol nitrogen, with hourly variations ranging from 5% to 64%. The study highlights the dynamic nature of ON sources and chemistry under different atmospheric conditions.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2023)
Article
Geochemistry & Geophysics
Rui Wang, Lin Su, Wai Kin Wong, Alexis K. H. Lau, Jimmy C. H. Fung
Summary: Accurate and timely rainfall nowcasting is crucial for public safety. While deep-learning models have outperformed traditional methods in heavy rainfall nowcasting, they still face limitations in forecast skills and increasing blurriness over time. This study introduces a new heavy rainfall nowcasting model, TS-RainGAN, that utilizes a task-segmented architecture with two modules: MaskPredNet predicts spatial coverage of rainfall categories, while IntensityGAN predicts rainfall intensity based on that coverage. TS-RainGAN accurately captures spatiotemporal features and provides skillful precipitation predictions with reduced blurriness, enabling competitive forecast skills for district-level nowcasting.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2023)
Article
Meteorology & Atmospheric Sciences
Shan Wang, Qiongqiong Wang, Yuk Ying Cheng, Hanzhe Chen, Zijing Zhang, Jinjian Li, Xin Feng, Zhe Wang, Jian Zhen Yu
Summary: Recent control efforts have successfully reduced fine-particulate-matter (PM2.5) pollution in Hong Kong. However, short-term PM2.5 pollution still occurs in winter and requires research on characterizing sources at an hourly timescale. This study provides insights into the hourly variations of PM2.5 sources in suburban Hong Kong during the winter of 2020 by analyzing chemical speciation and using tracer-based source apportionment. The results highlight the effectiveness of this approach in revealing hourly source variations and the importance of regional joint management to mitigate episodic PM2.5 pollution and associated health risks.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2023)