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ACS ES&T Air 2024年第7期1卷 628-636页

作者： Qingfeng Guo Wei Hu Min Hu Yujue Wang Song Guo Zhijun Wu Jing Zheng Limin Zeng State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences and Engineering International Joint Laboratory for Regional Pollution Control Ministry of Education (IJRC) Peking University Beijing 100871 China Institute of Surface-Earth System Science School of Earth System Science Tianjin University Tianjin 300072 China Collaborative Innovation Center of Atmospheric Environment and Equipment Technology Nanjing University of Information Science & Technology Nanjing 210044 China Key Laboratory of Marine Environment and Ecology Ministry of Education of China Ocean University of China Qingdao 266100 China

The thermal desorption (TD) technique has been widely employed to measure the molecular composition and volatility of organic aerosols through coupling to mass spectrometry. Although the impact of thermal decomposition on TD instruments has been discussed in the literature, its extent has not yet been quantified. Here, we quantify the decomposition of organic aerosol at the bulk level and qualitatively distinguish between compounds evaporating and decomposing at the molecular level through the combination of online thermodenuder aerosol mass spectrometer (TD-AMS), offline organic carbon/elemental carbon (OC/EC) analyzer, and ultra-high resolution mass spectrometer. Results show that up to 56% of organic mass in ambient aerosol decomposes at a desorption temperature lower than 180 °C, which means that large amounts of organics cannot be detected by TD-coupled instruments. Sulfur-containing compounds with larger molecular masses exhibit weaker thermal stability, making them more susceptible to thermal decomposition than other compounds not containing sulfur. This work provides a means to obtain quantitative and qualitative insights into the thermal decomposition of organic aerosol, which will aid in understanding secondary organic aerosol (SOA) formation and reducing the gap between SOA measurements and model simulations.

关键词： Aerosols Desorption Organic compounds Organic reactions Thermodynamic properties

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Agricultural Fire Impacts on Brown Carbon During Different Seasons in Northeast China

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SSRN 2023年

作者： Cheng, Yuan Cao, Xu-Bing Liu, Jiu-Meng Yu, Qin-Qin Zhang, Qiang He, Ke-Bin State Key Laboratory of Urban Water Resource and Environment School of Environment Harbin Institute of Technology Harbin150090 China Ministry of Education Key Laboratory for Earth System Modeling Department of Earth System Science Tsinghua University Beijing100084 China State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing100084 China

Brown carbon (BrC) represents not only a major component of haze pollution but also a non-negligible contributor to positive radiative forcing, making it a key species for coordinating air quality and climate policies. In China, field observations on BrC remain limited given the highly variable emission sources and meteorological conditions across different regions. Here we focused on the optical properties of BrC in a distinct but largely unexplored megacity in Northeast China, which is within a major agricultural region and experiences extremely cold winter. Agricultural fires were evident in April of 2021 and the fall of 2020, despite a toughest-ever policy on open burning. Such emissions enhanced BrC's mass absorption efficiency at 365 nm (MAE365), more efficiently by the fall fires which were inferred to have relatively high combustion efficiencies (CE). After taking CE into consideration, the relationships between MAE365 and the levoglucosan to organic carbon ratio (a measure of the significance of agricultural fire influence) roughly converged for the fire episodes of different seasons, including those identified in February and March of 2019 by a previous campaign. Agricultural fires also influenced the determination of absorption Ångström exponent (AAE), by resulting in non-linearity for BrC's absorption spectra shown on ln-ln scale. Based on three indicators developed by this study, the non-linearity was inferred to be caused by similar chromophores although the fires were characterized by various CE levels in different seasons. In addition, for the samples without significant influence of open burning, coal combustion emissions were identified as the dominant influencing factor for MAE365, whereas none solid link was found between the solution-based AAE and aerosol source. © 2023, The Authors. All rights reserved.

关键词： Light absorption

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Submarine groundwater discharge and associated nutrient fluxes in the Greater Bay Area, China revealed by radium and stable isotopes

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Geoscience Frontiers 2021年第5期12卷 397-410页

作者： Qianqian Wang Xuejing Wang Kai Xiao Yan Zhang Manhua Luo Chunmiao Zheng Hailong Li State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control School of Environmental Science and EngineeringSouthern University of Science and TechnologyShenzhenGuangdong 518055China School of Environmental Science and Engineering Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution ControlSouthern University of Science and TechnologyShenzhenGuangdong 518055China MOE Key Laboratory of Groundwater Circulation&Environment Evolution and School of Water Resources and Environment China University of Geosciences(Beijing)Beijing 100083China

The estuary-bay system is a common and complex coastal ***,quantifying submarine groundwater discharge(SGD)and associated nutrient fluxes in the complex coastal environment is challenging due to more dynamic and complicated riverine discharge,ocean processes and human *** this study,SGD and SFGD(submarine fresh groundwater discharge)fluxes were evaluated by combining stable and radium isotopes in the Guangdong-Hong Kong-Macao Greater Bay Area(GBA),a typical estuary-bay *** first built a spatially distributed radium mass balance model to quantify SGD fluxes in coastal areas of GBA integrating the Pearl River Estuary(PRE),bays and *** then used the stable water isotope(d2 H and d18O)end-member mixing model to distinguish submarine fresh groundwater discharge(SFGD)from *** on the 228Ra mass balance,the estimated SGD fluxes in the PRE,adjacent bay,and shelf areas were(6.14±2.74)×10^(8) m^(3) d^(-1),(3.00±1.11)×10^(7) m^(3) d^(-1),and(5.00±5.64)×10^(8) m^(3) d^(-1),*** showed that the largest area-averaged SGD was in the PRE,followed by that in the adjacent shelf and the *** differences may be mainly influenced by ocean forces,urbanization and benthic topographies controlling the variability of groundwater ***,the three end-member mixing model of ^(228)Ra and salinity was developed to confirm the validity of the estimated SGD using the Ra mass balance *** the two models,groundwater endmember and water apparent age estimation were the main sources of uncertainty in *** estimated SFGD flux was(1.39±0.76)108 m^(3) d^(-1),which accounted for approximately 12%of the total *** stable and radium isotopes was a useful method to estimate groundwater ***,the estimated SGD associated dissolved inorganic nitrogen(DIN)flux was one order of magnitude higher than other DIN *** was considered to be a significant contributor to the DIN loading to the *** findings

关键词： Radium isotopes Stable isotopes Submarine fresh groundwater discharge Nutrients Coastal aquifers Pearl River estuary

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Isotopes unveil overestimation of nutrient-driven oxygen deficit in the tidal rivers of Pearl River Delta during the wet season

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Science of the Total environment 2025年 958卷 178052页

作者： Wen, Jing Huang, Bangjie Huang, Zhiwei Jian, Hongxian Cao, Yingjie Tang, Changyuan Zeng, Fantang Li, Tong Fang, Huaiyang Du, Hongwei The Key Laboratory of Water and Air Pollution Control of Guangdong Province South China Institute of Environmental Sciences Ministry of Ecology and Environment Guangzhou510530 China National Key Laboratory of Water Environment Simulation and Pollution Control South China Institute of Environmental Science Ministry of Ecology and Environment Guangzhou510535 China School of Environmental Science and Engineering Sun Yat-Sen University Guangzhou510006 China Department of Horticulture Chiba University Matsudo648 Japan Guangdong Ecological and Environmental Monitoring Center Guangzhou510635 China

A low dissolved oxygen (DO) concentration in summer has been observed in river–estuary systems worldwide. Many studies have caused our stereotype that biochemical oxygen depletion was higher in summer than in winter;however, there was no direct evidence particularly in the tidal river with complex hydrological and biochemical processes. This study employed natural-abundance and labeled isotopes to quantify seasonal apportionment of biochemical oxygen depletion. In this study, apparent oxygen utilization (AOU) and carbon (C) and nitrogen (N) turnover potentials (nitrification rates and δ13C signals) were higher in the wet season than in the dry season. However, calculation results of the nitrification flux demonstrated that actual N turnover was constrained by shorter river residence time in the wet season. Similarly, the δ13C end-member mixing and Rayleigh fractionation models revealed that the conservative C behavior was more pronounced than degradation in situ in the river channel. Overall, C- and N-driven oxygen depletion accounted only for ~8% of AOU in the wet season. This substantiated that the hydrological control regulated C and N behaviors to "the conservative transport" to mitigate O2 depletion in the wet season. In contrast, a good correspondence between C and N turnover and low oxygen was recorded in the dry season. Therefore, the "nutrient- and non-nutrient-constrained DO cold spots" during the dry and wet seasons provided new insights into oxygen deficits in tidal rivers. Our study provided compelling evidence that seasonal apportionment of C- and N-driven oxygen depletion in situ has changed in tidal rivers. Biochemical oxygen depletion was more evident in the dry season than in the wet season;thus, it had been previously overestimated in the wet season, which will provide implications for using different water management strategies in different seasons. © 2024 Elsevier B.V.

关键词： Tidal stream

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Self-feedback LSTM regression model for real-time particle source apportionment

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Journal of environmental Sciences 2022年第4期34卷 10-20页

作者： Wei Wang Weiman Xu Shuai Deng Yimeng Chai Ruoyu Ma Guoliang Shi Bo Xu Mei Li Yue Li Trusted AI System Laboratory College of Computer ScienceNankai UniversityTianjin 300350China KLMDASR Tianjin Key Laboratory of Network and Data Security TechnologyTianjin 300350China State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control College of Environmental Science and EngineeringNankai UniversityTianjin 300071China Institute of Mass Spectrometry and Atmospheric Environment Guangdong Provincial Engineering Research Center for on-line source apportionment system of air pollution Jinan UniversityGuangzhou 510632China Guangdong-Hongkong-Macao Joint Laboratory of Collaborative Innovation for Environmental Quality Guangzhou 510632China

Atmospheric particulate matter pollution has attracted much wider attention *** recent years,the development of atmospheric particle collection techniques has put forwards new demands on the real-time source apportionments *** demands are summarized,in this paper,as how to set up new restraints in apportionment and how to develop a non-linear regression model to process complicated circumstances,such as the existence of secondary source and similar *** this study,we firstly analyze the possible and potential restraints in single particle source apportionment,then propose a novel three-step self-feedback long short-term memory(SF-LSTM)network for approximating the source *** proposed deep learning neural network includes three modules,as generation,scoring and refining,and regeneration *** from the scoring modules,SF-LSTM implants four loss functions representing four restraints to be followed in the apportionment,meanwhile,the regeneration module calculates the source contribution in a non-linear *** results show that the model outperforms the conventional regression methods in the overall performance of the four evaluation indicators(residual sum of squares,stability,sparsity,negativity)for the ***,in short time-resolution analyzing,SF-LSTM provides better results under the restraint of stability.

关键词： Time series Regression Self-feedback LSTM network Particle source apportionment

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Research on pollution identification and safety thresholds based on the olfactory effect on a halogenated hydrocarbon contaminated site

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Chemosphere 2024年 363卷 142914页

作者： Li, Xuwei Xie, Wenyi Zhang, Ya Chen, Yun Li, Mei Kong, Lingya Ding, Da Deng, Shaopo Nanjing Institute of Environmental Sciences Ministry of Ecology and Environment of China Nanjing210042 China State Environmental Protection Key Laboratory of Soil Environmental Management and Pollution Control Nanjing210042 China

To effectively address odor control issues at sites contaminated with halogenated hydrocarbons, it is essential to establish an odor risk prediction system for evaluating potential risks that may impact future planning. This research focuses on a representative halogenated hydrocarbon-contaminated site, examining the spatial and temporal distribution characteristics of key pollutants in soil gas. By analyzing odor contribution rates, the study identifies significant odorants in soil gas, which enables the derivation of both probabilistic and deterministic safety thresholds for soil and groundwater based on olfactory effects. The findings indicate that 1,1-dichloroethylene, vinyl chloride, chloroform, and 1,1-dichloroethane are prevalent throughout the contaminated site, displaying elevated concentration levels and substantially influencing the overall contamination extent. These substances are highlighted as critical pollutants requiring attention. Correlation analysis (P −1 for soil, and 9.29, 3.46, and 1.09, 69.55, and 47.01 mg L−1 for groundwater, respectively. Among them, the odor risks of chlorobenzene and 1,1-dichloroethylene warrant more attention than soil contamination risks;regarding 1,4-dichlorobenzene, it is recommended to concurrently consider odor risks during human health risk assessment;as for vinyl chloride and chloroform, their odor risks can be largely eliminated based on human health-oriented pollution management. © 2024 Elsevier Ltd

关键词： Chlorine compounds

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Long-Term Plume-Chasing Measurements: Emission Characteristics and Spatial Patterns of Heavy-Duty Trucks in a Megacity

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SSRN 2024年

作者： Yang, Pan Wang, Hui Wu, Xiaomeng Xiao, Shupei Zheng, Xuan You, Yan Zhang, Shaojun Wu, Ye 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 College of Chemistry and Environmental Engineering Shenzhen University Guangdong Shenzhen518060 China National Observation and Research Station of Coastal Ecological Environments in Macao Macao Environmental Research Institute Macau University of Science and Technology 999078 China

Assessing the emissions of heavy-duty diesel trucks (HDDTs) is crucial for managing air quality in megacities, especially concerning nitrogen oxides (NOX) and black carbon (BC). This study employed mobile plume chasing to monitor the real-world emissions of over 7,778 HDDTs in Shenzhen. The findings indicate that the real-world NOX emission factors (EF) of China IV trucks did not differ significantly from those of China III, whereas China V and VI vehicles demonstrated fleet-averaged reductions of 27% and 85%, respectively. For China V, a significant decrease in the NOX EF for HDDTs registered after 2017 was attributed to the installation of advanced aftertreatment systems, including diesel oxidation catalysts (DOC) and Diesel Particle Filters (DPF), along with selective catalytic reduction (SCR). These technologies led to an average reduction of 42% in NOX and 61% in BC emissions. Seasonal variations were pronounced, with winter (~20°C) NOX EF 40% higher than summer (~35°C) levels. Conversely, BC EF decreased by 26% in winter, indicating significant impacts of ambient temperature on emissions. Spatial analysis revealed that the average NOX EF of HDDTs on east freeways was 1.4 times higher than that on urban expressways, influenced by variations in the proportion of vehicle types segmented by usage. These findings offer a comprehensive perspective on HDDTs emissions, highlighting the importance of large-scale emission monitoring through plume chasing for precise and effective control of real-world HDDTs emissions. © 2024, The Authors. All rights reserved.

关键词： Nitrogen oxides

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Degradation behaviors of Nabumetone and its metabolite during UV/monochloramine process:Experimental and theoretical study

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Journal of environmental Sciences 2024年第8期142卷 103-114页

作者： Xiang Tu Yunsong Bai Qing Fu Sheng Chang Kunfeng Zhang Yang Pan Ruiyang Xiao Yifu Fu Qi Zhang State Key Laboratory of Environmental Criteria and Risk Assessment State Environmental Protection Key Laboratory of Drinking Water Source ProtectionResearch Centre of Lake EnvironmentNational Engineering Laboratory for Lake Pollution Control and Ecological RestorationChinese Research Academy of Environmental SciencesBeijing 100012China School of Environmental Science and Engineering Suzhou University of Science and TechnologySuzhou 215009China Institute of Environmental Engineering School of Metallurgy and EnvironmentCentral South UniversityChangsha 410083China School of Forestry Northeast Forestry UniversityHarbin 150040China

This study investigated degradation behaviors of a nonsteroidal anti-inflammatory drug Nabumetone(NMT)and its major metabolite 6-methoxy-2-naphthylacetic acid(MNA)in the coupling process of ultraviolet and monochloramine(UV/NH2Cl).The second-order rate constants of the contaminants reacting with reactive radicals(HO·,Cl·,Cl_(2)·-,and CO_(3)·^(-))were determined by laser flash photolysis ***·and Cl·contributed predominantly with 52.3%and 21.7%for NMT degradation and 60.8%and 22.3%for MNA *** presence of chlorides retarded the degradation of NMT,while promoted the destruction of MNA,which was ascribed to the photosensitization effects of MNA under UV *** functional theory(DFT)calculations revealed that radical adduct formation(RAF)was dominant pathway for both HO·and Cl·reacting with the contaminants,and hydrogen atom transfer(HAT)preferred to occur on side chains of NMT and *** reacted with NO_(2)·through single electron transfer(SET)with the second-order rate constant calculated to be 5.35×10^(7)(mol/L)^(-1)sec^(-1),and the contribution of NO_(2)·was predicted to be 13.0%of the total rate constant of NMT in pure water,which indicated that NO_(2)·played a nonnegligible role in the degradation of *** acute toxicity and developmental toxicity of NMT were enhanced after UV/NH_(2)Cl treatment,while those of MNA were *** transformation products of both NMT and MNA exhibited higher mutagenicity than their parent *** study provides a deep understanding of the mechanism of radical degradation of NMT and MNA in the treatment of UV/NH2Cl.

关键词： UV/NH_(2)Cl Reactive species Degradation kinetics Reaction mechanism Degradation products

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Photo-Anammox by Vacuum Ultraviolet Tandem Chlorine

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SSRN 2023年

作者： Liu, Wenzhe Chen, Baiyang Yang, Yang Li, Boqiang Pan, Huimei Luo, Wang State Key Laboratory of Urban Water Resource and Environment Shenzhen Key Laboratory of Organic Pollution Prevention and Control Harbin Institute of Technology Shenzhen518055 China

Excessive ammonia (NH4+) discharge can lead to algal blooms and disrupt water sustainability, so its control is imperative. Although microbiology-triggered anammox process is promising, its application is limited due to time-consuming cultivation of specific microorganisms and need for skilled operation. To bypass these barriers, this study proposed and verified a photo-induced anammox technology that removed ammonia and total nitrogen (TN) from water by applying ultraviolet (UV)/vacuum UV (VUV)/chlorine process under anoxic conditions. Under the Cl/N mass ratio of 5:1, the anoxic VUV/UV/chlorine process achieved 66.8% removal of 10 mg-N/L ammonia within 10 min, along with a 57.8% reduction in TN. Besides the evidence from TN loss, this study confirmed nitrogen gas (N2) as the primary degradation product. The selective conversion of ammonia into N2 was mainly attributed to reactive nitrogen species (RNS, 42.5%) and reactive chlorine species (RCS, 57.5%). The TN removal efficiency was insensitive to certain variations of pH (7.0–9.0), ammonia concentration (1–30 mg-N/L), chloride (50–125 mg/L), and sulphate (25–100 mg/L), but sensitive to dissolved oxygen and bicarbonate (25–100 mg/L). Given its robustness and high efficiency, the anoxic VUV/UV/chlorine technology may serve as a potentially promising alternative for ammonia and TN alleviation in wastewater. © 2023, The Authors. All rights reserved.

关键词： Ammonia

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Efficient Air Disinfection Achieved by Nanowire Modified Copper Mesh Electrodes

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SSRN 2023年

作者： Jin, Li Chen, Menghao Chen, Zhuo Li, Mengkai Yao, Maosheng Lu, Yun State Key Joint Laboratory of Environment Simulation and Pollution Control State Environment Protection Key Laboratory of Microorganism Application and Rick Control School of Environment Tsinghua University Beijing100084 China Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing100084 China Bioaerosol Laboratory School of Environmental Science and Engineering Peking University Beijing100084 China

The control of airborne pathogens is of great significance. Inactivation of microorganisms in water by nanowire electroporation has been well studied in recent years. But the effectiveness of nanowires modified electrodes for air disinfection is still unknown. In this study, a disinfection method for quick inactivation of bacteria in air is reported. The copper meshes were modified with Cu(OH)2 nanowires by electrochemical method. A flow-through device with nanowires modified electrodes inside was designed to generate, mix and disinfect bioaerosols. 60% ~ 85% inactivation efficiency for bacteria was achieved with a short air retention time of 0.3 s in high humidity. Endospores are equally sensitive to electric disinfection as the vegetable cells. The inactivation efficiency in moderate humidity could be significantly improved by coating with a high conductive material, PEDOT:PSS. The main inactivation mechanism in air was demonstrated as electroporation by detecting the membrane integrity. This novel disinfection method may be applied for the disinfection of air-transmitted pathogens in the future. © 2023, The Authors. All rights reserved.

关键词： Nanowires

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