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Compositional Variations of Primary Organic Aerosol Tracers of Pm2.5 in Shanghai During the 2019 China International Import Expo

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SSRN 2022年

作者： Di, Ruimiao Ma, Yingge Feng, Jialiang Zhu, Shuhui Zhou, Min Qiao, Liping Dai, Haixia Tian, Junjie Huang, Cheng Institute of Environmental pollution and health School of Environmental and Chemical Engineering Shanghai University Shanghai200444 China Shanghai Academy of Environmental Sciences Shanghai200233 China State of Environmental Protection Key Laboratory of the Formation and Prevention of Urban Air Complex Shanghai200233 China

Changes in the characteristics of the primary organic aerosol (POA) tracers in PM 2.5 are closely related to the changes in the corresponding pollution sources. Seven groups of PM 2.5 -bound POA tracers in urban Shanghai were analyzed before (BP), during (CIIE) and after (AP) the second China International Import Expo (October 28-November 17, 2019). Based on the diagnostic ratios of Levoglucosan (Levo) and its correlation with benzo[b]fluoranthene (B[b]F) and benzo[k]fluoranthene (B[k]F), Levo in PM 2.5 came from a mixed source of biomass burning (BB) and coal combustion. Low-molecular-weight n-alkanes (LMW-n-alkanes) were predominantly derived from anthropogenic emissions, while high-molecular-weight n-alkanes (HMW-n-alkanes) showed characteristics of plant-derived emissions. Plant wax n-alkanes (WAX C n ) correlated well with primary sugars (PSs) and sugar alcohols (SAs). The proportions of polycyclic aromatic hydrocarbons (PAHs) with different rings exhibited distinct diurnal variations. The increase in the proportion of HMW-PAHs at night was related to the increase in diesel vehicles. During CIIE, the air quality improved significantly and the concentrations of POA tracers showed a downward trend, but the proportion of POA tracers in PM 2.5 increased. Compared with the period before and after CIIE, the relative concentrations of POA tracers to element carbon (EC) increased by 26.2% and 19.2%, respectively. The proportion of HMW-PAHs increased slightly after CIIE, indicating the recovery of traffic. The percentage change of less than 0 for the relative concentration of SAs was by the dust episode. Among all the compounds measured, the most obvious increase was found in the relative concentration of n-alkanes during CIIE, though the relative concentration of WAX C n decreased, showing that the concentration of n-alkanes from other sources increased significantly. The results suggested that variations in POA tracers can reflect the changes during pollution episodes

关键词： Paraffins

Determination of Arsenic and Antimony by Atmospheric Pressure Glow Discharge Portable Emission Spectrometer with Solid Acid Hydride Generation

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SSRN 2023年

作者： Han, Shanru Zhu, Zhenli Liu, Ying Dong, Junhang Xu, Chaoyu Liu, Xing Liu, Jinzhao Zheng, Hongtao State Key Laboratory of Biogeology and Environmental Geology School of Earth Sciences China University of Geosciences Wuhan430074 China School of Mechanical Engineering and Electronic Information China University of Geosciences Wuhan430074 China State Environmental Protection Key Laboratory of Source Appointment and Control of Aquatic Pollution Ministry of Ecology and Environment China Faculty of Material Science and Chemistry China University of Geosciences Wuhan430074 China

In this work, the use of solid acid hydride generation (HG) for the simultaneous determination of As and Sb in environmental water samples by miniaturized atmospheric pressure glow discharge plasma atomic emission spectrometer (APGD-OES) was evaluated. It was found that HG with the use of sulfamic acid tablets can achieve similar sensitivity with conventional HCl-KBH4 for As and Sb determination by APGD-OES, which avoids the safety problem caused by the use of hydrochloric acid and greatly facilitates field analysis. In addition, the whole detection procedure does not require complex pretreatment of liquid samples, thereby enabling analysis in an environmentally friendly manner. Under optimal conditions, the obtained detection limits (LODs) are as low as 1.14 μg L-1 for As and 0.62 μg L-1 for Sb, respectively. In addition, it offers good repeatability, where the relative standard deviations (RSDs) are less than 5% at 20 μg L-1. The accuracy of the proposed method was validated by the analysis of simulated natural water reference samples. Moreover, it has been successfully applied to the determination of tap water, pond water, and hot spring samples. All these results clearly demonstrate the proposed simple, cost-effective and field-deployable method provides a promising approach for the field analysis of As and Sb. © 2023, The Authors. All rights reserved.

关键词： Arsenic

Cfd-Dem Simulations of a Gas-Solid-Liquid Fluidization System: Effects on the Flow Field and Particle Behavior of Semi-Dry Desulfurization Fluidized Bed

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SSRN 2023年

作者： Zhu, Linhang Zhao, Zhongyang Liu, Chang Zhang, You Zhang, Yongxin Zheng, Chenghang Luo, Kun Gao, Xiang State Key Lab of Clean Energy Utilization State Environmental Protection Engineering Center for Coal-Fired Air Pollution Control Zhejiang University Hangzhou310027 China Key Laboratory of Clean Energy and Carbon Neutrality of Zhejiang Province Hangzhou310027 China Jiaxing Research Institute of Zhejiang Province Jiaxing314031 China

Gas-solid-liquid multiphase flow systems have been widely applied in energy engineering, petrochemical industries, biochemical industries and food industries, etc., which usually involve multi-physical processes and multi-reaction stages. As a typical gas-solid-liquid multiphase flow system, the semi-dry flue gas desulfurization fluidized bed has been widely applied by small and medium-scale thermal power plants attribute to its advantages of excellent mixing effect, relatively high efficiency and low cost. This study focused on the fluid hydrodynamics, wet particle motions and the transfer efficiency (SO2 removal efficiency) in a fluidized bed via two-way coupled CFD-DEM numerical simulations with the implementation of different semi-dry desulfurization stages ("constant-rate" absorption stage, "falling-rate" absorption stage and solid absorption stage) as well as the consideration of liquid bridge force. To avoid the fast evaporation of small droplets, simulations based on larger particles (Geldart group D) were also conducted to clarify the influence of varying liquid volume contents. Results revealed that the existence of liquid layers would partly enhance the desulfurization efficiency, while in this case the bed exhibits poor fluidization characteristics. Adding humification water in the solid absorption stage would transform the reaction stage from solid absorption stage to "constant-rate" absorption stage, which improves the desulfurization efficiency significantly. It could also be summarized that the increase of Ca/S molar ratio would enhance the desulfurization efficiency partly, but the improvement would not be obvious when the Ca/S molar ratio is greater than a certain range. © 2023, The Authors. All rights reserved.

关键词： Fluidized beds

Intelligent Sniffer: A Chip-Based Portable E-Nose for Accurate and Fast Essence Evaluation

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SSRN 2024年

作者： Jiang, Yiwei Wang, Ziyi Hu, Yan Lin, Wenhao Yao, Longchao Xiao, Wenfang Hu, Jiangxue Liu, Weijie Zheng, Chenghang Chen, Linghong Gao, Xiang State Key Laboratory of Clean Energy Utilization State Environment Protection Engineering Center for Coal-Fired Air Pollution Control Zhejiang University Hangzhou310027 China Ningbo Innovation Center Zhejiang University Ningbo315100 China Zhejiang Ecological and Environmental Monitoring Center Hangzhou310012 China Jiaxing Research Institute Zhejiang University Jiaxing314000 China

Electronic nose (e-nose) is capable of identifying gases of different odors and concentrations. However, accurate odor evaluation of complicated volatile compounds (e.g., from essence) at human perception level remains challenging, especially in a fast and cheap way. This study presents a portable e-nose designed to evaluate different essence samples and their mixtures that outperforms human olfaction. Given the complexity and similarity of ingredients among different essence types, six sensors were integrated on a miniaturized chip after the sensor array optimization from 18 gas-sensing materials with varying doping, film thicknesses, operated at different temperatures. A pattern recognition model based on Long-short term memory network and convolutional neural network was developed to automatically extract sensors’ dynamic response features to determine essence type and concentration. Our e-nose exhibited high sensitivity and repeatability to analyze low-concentration essence volatiles better than human olfactory tests. The classification accuracy for four similar textile essence and their mixtures could reach up to 96.9%. And the R2 and RMSE for relative concentration achieved 0.98 and 0.068%, respectively. Furthermore, only the first 60 s signals are needed for the sample analysis which significantly reduced the sample testing time compared to the traditional base-peak-base test method (over 200 s). This research provides a favorable opportunity for essence fragrance prediction in various applications such as food, textile, cosmetics, etc. © 2024, The Authors. All rights reserved.

关键词： Electronic nose

Impact of Commercial Cooking on Urban PM2.5 and O3 with Realtime Data-Assisted Emission Inventory

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SSRN 2022年

作者： Yuan, Yingzhi Zhu, Yun Lin, Che-Jen Wang, Shuxiao Xie, Yanghong Li, Haixian Xing, Jia Zhao, Bin Zhang, Mengmeng You, Zhiqiang Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control College of Environment and Energy South China University of Technology Guangzhou Higher Education Mega Center Guangzhou510006 China Department of Civil and Environmental Engineering Lamar University BeaumontTX77710 United States State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing100084 China State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex Beijing100084 China Shunde Branch of Foshan Ecological Environment Bureau Foshan528000 China

Commercial cooking (CC) is an intensive near-field source contributing to ambient PM2.5 and O3 concentration in urban areas. Compilation of CC emission inventories (EI) has been challenging due to the dynamic variation of the emission sector, which has resulted in lack of data, underestimated quantity and poor temporal-spatial resolution. A pilot study was carried out to develop a methodology that integrates existing emission statistics with online oil fumes monitoring (OOFM) data for developing a high temporal-spatial resolution EI of CC. With the updated emission inventory, the impacts of CC emission on local PM2.5 and O3 were evaluated using WRF-CMAQ and model-monitor data fusion tool of SMAT-CE in Shunde, China. The developed methodology gave an emission estimate significantly different from legacy inventory in terms of emission quantity and temporal allocation. Altogether, the OOFM data-assisted EI led to better simulation performance of spatiotemporal variations on model-predicted PM2.5 and O3 concentrations. The simulation results using the newly CC inventory indicated that the emissions in this sector contributed 1.25 ± 2 μg/m3 of PM2.5, and accounted for 24 ± 1 % of PM2.5 concentration derived from local anthropogenic emissions. Moreover, a higher contribution of CC to PM2.5 was predicted in the near field of high-emission areas, while the contribution to O3 was insignificant. © 2022, The Authors. All rights reserved.

关键词： Image resolution

Role of Black Carbon in Modulating Aerosol Direct Effects Driven by air pollution controls During 2013-2017 in China

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SSRN 2022年

作者： Zhang, Fenfen Xing, Jia Ding, Dian Wang, Jiandong Zheng, Haotian Zhao, Bin Qi, Ling Wang, Shuxiao State Key Joint Laboratory of Environmental Simulation and Pollution Control School of Environment Tsinghua University Beijing100084 China State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex Beijing100084 China Institute for Atmospheric and Earth System Research Faculty of Science University of Helsinki Helsinki00014 Finland School of Atmospheric Physics Nanjing University of Information Science and Technology Nanjing210044 China School of Energy and Environmental Engineering University of Science and Technology Beijing Beijing100083 China

Aerosol direct effects (ADEs) can modulate shortwave radiation as well as atmospheric dynamics and air quality. As the key absorbing component of aerosol, the black carbon (BC) largely determines the aerosol optical properties. Therefore, it is expected that BC emission controls might gain co-benefits from the simultaneous reduction of ADEs. To demonstrate such synergy, we quantified the ADEs changes and role of BC controls in China during 2013-2017 using a regional two-way coupled meteorology chemistry transport model. Results suggest that the control action effectively reduced wintertime PM2.5 concentration (-26.0 μg m-3) and associated ADEs. The influence of ADEs on surface shortwave radiation, 2-meter temperature, and planetary boundary layer height was weakened from -16.7 W m-2, -0.20°C, and -15.4 m in 2013 to -11.3 W m-2, -0.06°C, and -10.7 m in 2017, respectively. The enhancement of SO2, NO2, and PM2.5 concentrations due to ADEs was reduced from +3.1%, +5.2%, and +5.4% in 2013, to +2.6%, +4.5%, and +3.3% in 2017, respectively, demonstrating the extra benefit of air pollution controls by reducing ADEs. The BC emission reduced by 12.5% simultaneously along with the effective controls during 2013-2017. Such BC controls contributes 15.6-60.2% of such changes in the ADEs influence on meteorological variables, and 32.6-41.1% on air pollutants. More specially, the effectiveness of collaborative reduction of BC further reduced surface shortwave radiation in China by 3.6 W m-2 in January and 1.0 W m-2 in July, leading to a more weakened ADEs that bring extra benefits in reducing PM2.5 concentrations by 1.8 μg m-3 in January and 0.3 μg m-3 in July. Apparently, BC played a dominant role in modulating the ADEs and associated influences on meteorology and air quality, suggesting a wise control strategy by targeting absorbing component of PM2.5 reduction to address both air pollution and climate change in the future. © 2022, The Authors. All rights reserved.

关键词： air quality

Heavy-Duty Diesel Trucks on Highways in Beijing-Tianjin-Hebei: Constant Challenge in pollution control

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SSRN 2024年

作者： Han, Yingying Wang, Chang Zhu, Yixue Wu, Rui Xue, Yifeng Zhang, Xiang Wang, Weiwei Cui, Yangyang Han, Jinxiu Shi, Zongbo Wang, Xiuyan Jin, Taosheng Tianjin Key Laboratory of Urban Transport Emission Research State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control College of Environmental Science and Engineering Nankai University Tianjin300350 China Advanced Institute of Natural Sciences Beijing Normal University Zhuhai519087 China School of Environment Beijing Normal University Beijing100875 China Laboratory of Transport Pollution Control and Monitoring Technology Transport Planning and Research Institute Ministry of Transport Beijing100028 China National Engineering Research Center of Urban Environmental Pollution Control Beijing Municipal Research Institute of Eco-Environmental Protection Beijing100037 China Sustainable Development Research Institute for Economy and Society of Beijing School of Management and Economics Beijing Institute of Technology Beijing100081 China School of Geography Earth and Environmental Sciences The University of Birmingham BirminghamB15 2TT United Kingdom

Heavy-duty diesel trucks (HDDTs) contributed significantly to on-road air pollution. This study measured the traffic flow of HDDTs on seven national highways in Beijing-Tianjin-Hebei (BTH) region to estimate air pollutants of HDDTs from 2016 to 2020. The emission factors are corrected by the International Vehicle Emissions (IVE) model, traffic flow, and road length. Compared with 2016, traffic flow in 2019 increased by 41%, carbon monoxide (CO) and nitrogen oxide (NOx) emissions increased by 0.3% and 4%, while hydrocarbons (HC) and particulate matter (PM) emissions decreased by about 26% and 18%. The COVID-19 lockdowns did not cause significant annual changes in traffic flow and pollution emissions in 2020 compared with 2019, but there were substantial monthly variations in pollutant emissions. Our study showed that although control measures were implemented during the "Thirteenth Five-Year Plan" period, the substantial increase in regional HDDT transport posed a continuing challenge in reducing road traffic emissions. © 2024, The Authors. All rights reserved.

关键词： COVID-19

The Research on Co Oxidation Over Ce-Mn Oxides: The Preparation Method Effects and Oxidation Mechanism

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SSRN 2023年

作者： Ye, Zhiping Liu, Yang Nikiforov, Anton Ji, Jiayu Zhao, Bo Wang, Jiade College of Environment Zhejiang University of Technology 18 Chaowang RD Hangzhou310014 China Ghent University Faculty of Engineering Department of Applied Physics Research Unit Plasma Technology Sint-Pietersnieuwstraat 41 Ghent9000 Belgium Zhejiang Tuna Environmental Science & Technology Co. Ltd Shaoxing312071 China State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex Beijing100084 China

A series of CeO2-MnOx for highly efficient catalytical oxidation of carbon monoxide were prepared by citrate sol-gel (C), hydrothermal (H) and hydrothermal-citrate complexation (CH) methods. The outcome indicates that the catalyst generated using the CH technique (CH-1:8) demonstrated the greatest catalytic performance for CO oxidation with a T50 of 98°C, and also good stability in 1400 min. Compared to the catalysts prepared by C and H method, CH-1:8 has the highest specific surface of 156.1 m2/g, and the better reducibility of CH-1:8 was also observed in CO-TPR. It is also observed the high ratio of adsorbed oxygen/lattice oxygen (1.5) in the XPS result. Moreover, characterizations by the TOF-SIMS method indicated that obtained catalyst CH-Ce/Mn=1:8 had stronger interactions between Ce and Mn oxides, and the redox cycle of Mn3++Ce4+→ Mn4++Ce3+ was a key process for CO adsorption and oxidation process. According to in-situ FTIR, the possible reaction pathway for CO was deduced in three ways. CO directly oxidize with O2 to CO2, CO adsorbed on Mn4+ and Ce3+ reacts with O to form intermediates (COO-)(T>50°C) and carbonates (T>90°C), which are further oxidized into CO2. © 2023, The Authors. All rights reserved.

关键词： Carbon dioxide

Applying Machine Learning to Construct Braking Emission Model for Real-World Road Driving

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SSRN 2022年

作者： Wei, Ning Men, Zhengyu Ren, Chunzhe Jia, Zhenyu Zhang, Yanjie Lv, Zongyan Guo, Dongping Guo, Jiliang Chang, Junyu Wu, Lin Peng, Jianfei Wang, Ting Zhang, Qijun Mao, Hongjun Tianjin Key Laboratory of Urban Transport Emission Research & State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control College of Environmental Science and Engineering Nankai University Tianjin300071 China Tianjin Youmei Environment Technology Ltd. Tianjin300300 China

Brake emission s from vehicles are increasing as the number of vehicles ***, current research on brake emissions, particularly the intensity and characteristics of emissions under real road conditions ,is significantly inadequate compared to exhaust emissions. To this end, a dataset of 600 brake pad segments was constructed and a mapping function between the average brake emission intensity of PM 2.5 from the segments and the segment features was established by five algorithms (multiple linear regression (MLR) and four machine learning algorithms).Based on the five algorithms, the importance of the different features of the fragments was discussed and brake energy intensity (BEI) and brake pad metal content ( MC ) were identified as the most significant factors affecting brake emissions and used as the final modeling *** the five algorithms, categorical boosting (CatBoost) had the best prediction performance, with a mean R 2 and RMSE of 0.83 and 0.039 respectively for the tenfold *** addition, the CatBoost-based model was further compared with the MOVES model to demonstrate its *** CatBoost-based model has better prediction performance than the MOVES *** MOVES model overpredicts brake fragment emissions for urban roads and underpredicts brake fragment emissions for motorways. Furthermore, the CatBoost-based model was interpreted and visualized by an individual conditional expectation (ICE) plot to break the machine learning black box, with BEI and MC showing nonlinear monotonic increasing relationships with braking *** plot also provides viable technical solutions for controlling brake emissions in the future. Both avoiding aggressive braking driving behavior (e.g., the application of smart transportation technologies) and using brake pads with less metal content (e.g., using ceramic brake pads) can effectively reduce brake *** construction of a machine learning-based brake emission mod

关键词： Brakes