Based on multi-source environmental and meteorological observations combined with WRF-Chem numerical simulations, the three-dimensional evolution of a typical ozone (O₃) pollution episode in Anhui Province was comprehensively investigated. The relative contributions of atmospheric physical and chemical processes, including chemical reactions, advective transport, and turbulent mixing, to O₃ concentration changes were quantified. The synergistic influence mechanism of these physical and chemical processes, coupled with diurnal variations in atmospheric boundary layer (ABL) structures on surface O₃ pollution was also revealed. During the pollution episode on June 1~3, 2022, three-quarters of the cities exceeded the national O₃ pollution standard, with O₃ concentrations higher in the north and lower in the south, a pattern controlled by local meteorological conditions. This O₃ pollution episode was influenced by the combined impact of two major source regions: North China Plain and Yangtze River Delta. In the early stage, northwesterly airflow transported O₃ from North China Plain to northern Anhui, where local wind convergence, together with unfavourable meteorological conditions of high temperature and low humidity, triggered severe O₃ pollution. In the later stage, southeasterly winds prevailed, driving the northward transport of O₃ from Yangtze River Delta to Anhui and prolonging the pollution period. The model results indicated that the diurnal variation of O₃ budget showed a bimodal distribution, with turbulent mixing and horizontal transport processes dominating the peaks at 09:00 and 17:00, respectively, and consequently delaying the O₃ concentration peak to 18:00. The influence of regional O₃ transport exhibited a temporal lag effect: during the daytime, transport within the ABL at approximately 500m directly affected surface O₃ concentrations in adjacent areas; whereas at night, transport within the residual layer at approximately 1km dominated, interacting with diurnal ABL variations, thus exacerbating O₃ pollution in distant downstream areas.

Under the unique topographic conditions of a deep basin, the Sichuan Basin was characterized by distinct air pollution complex patterns. A typical air pollution complex event and its meteorological drivers in the Sichuan Basin during spring 2024 were investigated, based on air pollutant monitoring data and ERA5 meteorological reanalysis. The results demonstrate that: (1) The southern part of the basin, particularly the region encompassing Yibin, Zigong, and Luzhou, was identified as a high-incidence area for air pollution complex of O₃ and PM_2.5. From March 22 to 24, 2024, the average near-surface maximum daily 8-h average (MDA8) O₃ and daily average PM_2.5 concentrations in these three cities were measured at 196.3μg/m³ and 66.6μg/m³, respectively, and synchronous variations in near-surface O₃ and PM_2.5 concentrations were observed. This episode was characterized as a typical air pollution complex event in southern Sichuan, with concurrently high levels of both O₃ and PM_2.5 (a "dual-high" pattern). (2) Compared to the same period in 2021~2023, the averages of near-surface O₃ and PM_2.5 concentrations in these three cities during March 22~24, 2024, were found to be abnormally elevated by 83.4μg/m³ (99.6%) and 26.9μg/m³ (77.3%), respectively, indicating an unusually anomalous spring air pollution complex event. (3) The typical air pollution complex of O₃ and PM_2.5 was significantly influenced by meteorological conditions. Local high air temperatures and strong solar radiation were identified as factors that promoted photochemical O₃ generation and secondary PM_2.5 formation. Additionally, the convergence of northeasterly surface winds from the basin at the southern edge of the Sichuan Basin was observed to exacerbate the local accumulation of air pollutants. Through this case study, the unique characteristics and meteorological mechanisms of air pollution complex of O₃ and PM_2.5 in the Sichuan Basin were elucidated, providing scientific support for regional joint prevention and control strategies.

Nitrated polycyclic aromatic hydrocarbons (NPAHs) and oxygenated polycyclic aromatic hydrocarbons (OPAHs) are two important derivatives of polycyclic aromatic hydrocarbons (PAHs). Samples from households in Tianjin indoor dust deposition were collected from April to May 2023 in this study. The concentrations of 18NPAHs and 5OPAHs were analyzed by GC-MS, and the concentration characteristics and source apportionment of these substances were discussed. The results showed that the median concentrations of ∑₁₈NPAHs and ∑₅OPAHs in Tianjin indoor dust deposition were 37.95 and 248.82ng/g, respectively. The median concentrations of ∑₁₈NPAHs and ∑₅OPAHs in the urban area were slightly higher than those in the surrounding urban area.There were no significant differences in these substance concentrations of ∑₁₈NPAHs and ∑₅OPAHs between the urban area and the surrounding urban area in Tianjin. From the perspective of different influencing factors, there was a statistically significant difference in the impact of smoking habits and energy types on the monomer concentrations of some NPAHs and OPAHs in Tianjin indoor dust deposition. The results of the characteristic ratio method showed that NPAHs in Tianjin indoor dust deposition mainly originated from primary emissions of combustion sources and vehicle exhaust emissions, and some secondary generation mainly formed by OH· catalytic reactions.

Biodiesel is recognized as a carbon-neutral fuel, yet its impact on the emissions of key carbonaceous components from diesel engine exhaust remains unclear. To investigate the influence of biodiesel on carbonaceous component emissions from agricultural machinery, this study conducted real-world measurements to systematically analyse the effects of multiple factors-including biodiesel blend ratio (B0, B5, B20), emission standard (China Ⅱ, China Ⅲ), machinery type, and operating conditions-on the chemical composition of organic carbon (OC) and elemental carbon (EC) (divided by thermal stability into OC1-OC4 and EC1-EC3). The results indicated that: (1) The emission factors of OC and EC (EF_OC and EF_EC) were significantly reduced by biodiesel blending. For instance, EF_OC and EF_EC were reduced by 44.6% and 24.3%, respectively, for B20compared to B0, which was primarily attributed to increased fuel oxygen content and improved combustion efficiency. (2) The formation of OC and EC subcomponents was jointly influenced by fuel properties and combustion temperature. In emissions from B5machinery, the proportions of OC1 and OC2 were decreased, while that of EC2 was increased. (3) Based on emission factor estimates, the total national OC and EC emissions from agricultural machinery in China in 2022 were calculated to be 10608t and 2507t, respectively, accounting for 27.6% and 9.4% of road mobile source emissions. If B5 and B20 were widely adopted, total OC emissions from agricultural machinery could be reduced by 35.8% and 44.2%, respectively, compared to the B0 baseline.

Based on the hourly ozone (O₃) concentration data, tropical cyclone (TC) data and meteorological reanalysis data in the Pearl River Delta (PRD) during the warm season (June-September) from 2015 to 2023, the impacts of various meteorological events, including isolated heat wave (HW) events, isolated TC events, and TC-HW compound events on O₃ in PRD and their interannual variation relationship with O₃ pollution events were compared and analyzed. The results showed that TC-HW compound events were associated with an average O₃ concentration of (143.8±41.7) μg/m³, representing a mean growth rate of 21.4%, and a 36.8% likelihood of O₃ pollution occurrence. Compared with other event categories, TC-HW compound events lead to an average regional O₃ increase of 38.3μg/m³. A statistically significant positive correlation (r=0.68, P<0.05) was identified between the frequency of TC-HW compound events and the interannual variability of O₃ pollution episodes. Meteorological conditions characterized by reduced cloud cover, low relative humidity, weakened wind speed, and enhanced solar radiation during the TC-HW compound events were identified as key drivers of increased O₃ concentrations in the PRD.

To understand the recent trends in ozone (O₃) pollution and the contribution of regional background in the Huai River Basin (HRB), this study utilized the Tracking Air Pollution in China (TAP) dataset (2014~2024) and ERA5_Land meteorological reanalysis data. Principal component analysis (PCA) and the regional background estimation method proposed by the Texas Commission on Environmental Quality (TCEQ) were employed to calculate the contribution rate of regional background O₃ (O₃ concentration without precursor emissions) in the HRB. Additionally, the eXtreme Gradient Boosting (XGBoost) model and SHapley Additive exPlanations (SHAP) were applied to explore the influence of meteorological factors on regional background O₃.The results indicate that from 2014 to 2024, the daily maximum 8-hour average (O₃-8h) concentration in the HRB increased at a rate of 2.87μg/m³ per year. The regional background O₃ estimated by PCA and TCEQ exhibited a strong correlation (R² = 0.89, P< 0.01), though PCA-derived values were slightly higher, with significantly reduced differences during warm seasons. The estimated average contribution of regional background to O₃-8h in the HRB was 85.8%, with contributions ranging from 71.1% to 86.0% in four key cities (Zhengzhou, Hefei, Qingdao, and Xuzhou). Over the study period, the regional background contribution rate increased by an average of 11.5%, suggesting that enhanced regional transport is a major factor driving elevated surface O₃ levels.Regional background O₃ was influenced nonlinearly by multiple meteorological factors. The dominant factors were surface downward solar radiation in spring and autumn, 2-meter temperature in summer, and a combination of 2-meter temperature and surface downward solar radiation in winter. Overall, high humidity, strong downward surface thermal radiation, high pressure, and strong westerly/northerly winds suppressed regional background O₃ concentrations in the HRB.

This study investigated the spatiotemporal variations and relationships of O₃, HCHO, and NO₂, as well as O₃ formation sensitivity (OFS) and the distribution changes of O₃-NO_x-VOCs control regime in the Beijing-Tianjin-Hebei (BTH) region from 2019 to 2023, using data acquired from the TROPOMI satellite sensor and ground-based monitoring networks. The results showed that: (1) O₃ concentrations in the BTH region were characterized by higher levels in the south and lower levels in the north, with an overall trend of initial decrease followed by an increase. The number of O₃ pollution days was reduced by approximately 30%. A significant positive correlation was observed between O₃ concentration and air temperature (r=0.85, P<0.001). (2) High-value areas of HCHO and NO₂ vertical column densities (VCDs) were concentrated in the Beijing-Tianjin-Langfang/Tangshan regions and the Shijiazhuang-Handan-Xingtai urban agglomeration. During the study period, a decrease of approximately 3% in HCHO VCDs and about 12% in NO₂VCDs was recorded. HCHO variations were significantly influenced by temperature, while NO₂ was primarily driven by anthropogenic activities. Based on daily data during the OPHF period in the BTH region, nonlinear relationships between O₃ concentration and the ratio of HCHO to NO₂ VCDs (FNR) were found to be consistent with photochemical models of O₃-NO_x-VOCs reactions. The peak O₃ concentration occurred at an FNR value of 4.0, with the transitional regime ranging from 3.2 to 4.9. Although differences were observed in the fitting curves between O₃ concentration and FNR across different cities, the correlation coefficients were all above 0.65. (3) From 2019 to 2023, the O₃ formation regime during the OPHF period was shown to transition from mixed NO_x-VOCs limited to VOCs limited conditions, with the area of VOCs limited regime expanding by approximately 23%. Therefore, it is suggested that greater emphasis should be placed on reducing VOCs emissions to mitigate O₃ pollution in the future. Ozone formation sensitivity was significantly influenced by anthropogenic factors. The Pearson correlation coefficients between FNR and NO₂ VCDs, CO VCDs, and HCHO VCDs were -0.86, -0.62, and 0.14 (P<0.001), respectively. Among meteorological factors, temperature and humidity were found to have significant effects on FNR, with correlation coefficients of 0.88 and 0.41 (P<0.001), respectively.

An integrated electrochemical-coupled membrane reactor system was constructed, where a conductive ceramic membrane (CCM) cathode fabricated by spray pyrolysis-in situ precipitation and a Ti/RuO₂-IrO₂ anode were employed to investigate the mitigation mechanism of membrane fouling during electric field-assisted oil-containing wastewater treatment. It was demonstrated that a stable Sb-SnO₂ conductive coating was successfully deposited on the CCM electrode surface through the spray pyrolysis-in-situ precipitation method, exhibiting an average roughness of approximately 324nm, which represented a 32% reduction compared to the pre-modified state. Under an electrochemical potential of -1.0V, the CCM electrode was characterized by an impedance value of 38 Ω·cm² and a corrosion potential of -0.36V, indicating excellent electrode stability and corrosion resistance. In oily wastewater treatment experiments, when the applied electric field intensity was varied between 0.6~9.8V/cm, the flux decline rate of the CCM membrane was observed to progressively decrease with increasing electric field intensity. The flux decay rate was found to stabilize when the electric field intensity reached 4.2V/cm. After five cycles of hydraulic backwashing, the CCM membrane flux was measured to be 15%~17% higher for both 0.1g/L and 0.5g/L oily wastewater concentrations compared to non-electrified conditions, demonstrating extended membrane service life. Membrane fouling characterization revealed that the modified CCM exhibited enhanced hydrophilicity and surface electronegativity, which generated strong repulsive forces against oil droplets (Zeta potential: -35.2 to~16.7mV) during electric field-assisted separation. Analysis of the membrane fouling mechanism indicated that the electric field application significantly improved the irreversibility of membrane fouling, with the fouling process being transformed from a standard clogging model to a complete clogging model. These findings further confirmed the critical role of electric fields in mitigating membrane fouling progression.

This study designed and operated two sets of A²/O-self-forming dynamic membrane reactors: one with aeration inside the membrane module and the other without aeration (control group). The dynamic membrane structure, membrane fouling, and treatment efficiency of both systems were systematically investigated. The results showed that the permeate flux and treatment efficiency were comparable between the two systems during the initial operational stage. However, as operation duration increased, the control group gradually developed a dynamic layer dominated by anoxic/anaerobic sludge, whereas the aerated group formed a dynamic layer with an alternating aerobic-anoxic-anaerobic structure. Compared to the control group, the aerated system developed a porous, network-like dynamic layer composed primarily of filamentous aerobic sludge, which significantly improved permeate flux and extended operational duration by nearly 40%. Furthermore, the extensive anoxic/anaerobic zones in the control group's dynamic membrane led to the death of aerobic microorganisms and the subsequent release of organic nitrogen and phosphorus. Consequently, the effluent concentrations of ammonia nitrogen and total phosphorus exhibited a gradual increase over time. In contrast, the aerated group maintained higher microbial activity in its dynamic layer, and the alternating aerobic-anoxic-anaerobic activated sludge configuration facilitated simultaneous nitrification-denitrification, significantly reducing effluent concentrations of both ammonia nitrogen and total phosphorus.

Although long-term studies on enhanced biological phosphorus removal systems and biofilm-based phosphorus enrichment processes have established the crucial involvement of extracellular polymeric substances (EPS), the mechanisms by which EPS participate in phosphorus uptake and release remain debated. Key points of contention include whether EPS exhibit independent phosphorus sequestration and release capabilities distinct from cellular metabolic activities, and whether biochemical reactions or physico-chemical precipitation processes dominate within EPS. This review summarizes major findings from previous research on phosphorus uptake and release mechanisms mediated by EPS. Based on the transport and transformation behavior of phosphorus and its compounds in environmental systems, as well as critical phenomena recently observed in sequencing batch biofilm reactors for phosphorus removal and enrichment, a new hypothesis is proposed: under redox-regulated conditions, the dominant mechanism of EPS in biological phosphorus cycling involves physico-chemical processes of binding/fixation and dissociation/mobilization, while phosphorus migration between EPS and the aqueous phase is primarily diffusion-driven. This hypothesis offers an integrated framework for explaining phosphorus translocation and transformation between EPS and the solution, helps to reconcile existing controversies and unanswered questions in the literature, and provides a novel theoretical basis for understanding the role of EPS in biological phosphorus removal processes.

With the escalating problem of nitrogen pollution in aquatic ecosystems, heterotrophic nitrification-aerobic denitrification (HN-AD) bacteria have gained considerable attention due to their capability for simultaneous nitrification and denitrification. This technology presents benefits over conventional segmented treatment, such as high efficiency and strong adaptability. Nevertheless, there are still issues with the actual applications of HN-AD bacteria, such as unstable nitrogen removal, poor microbial community stability, and uncertain metabolic mechanisms. In this paper, the research methods applied in HN-AD studies, encompassing the techniques for isolation, screening of functional strains, as well as factors influencing nitrogen removal, were comprehensively reviewed. The application of modern omics technologies in elucidating HN-AD metabolic pathways was also discussed. Six key strategies for nitrogen removal enhancement were analyzed in detail: bacterial immobilization, co-cultivation of multiple strains, breeding of high-efficiency strains, regulation of intermediate metabolites, optimization of electron transfer, and quorum sensing interference. Furthermore, their underlying mechanisms for improving nitrogen removal efficiency was also systematically elucidated. Finally, the prospective research directions for HN-AD bacteria were put forward, aiming to provide valuable insights for translating this technology from laboratory research to engineering applications.

The rapid startup and stable operation of the partial denitrification/anammox (PD/A) system remain challenges limiting their engineering application in wastewater nitrogen removal. This study investigates the startup process of a PD/A reactor, inoculated with an aerobic sludge biofilm, under conditions of low substrate concentrations (NH₄⁺-N < 50mg/L, NO₃^--N < 30mg/L) and a C/N ratio of 2.86. After 100d of operation, the system successfully enriched both anaerobic ammonium-oxidizing bacteria (AnAOB) and partial denitrification bacteria (PDB), achieving stable operation. By the end of Phase Ⅳ, the total nitrogen removal rate (Re. TN) and nitrogen removal rate (NRR) stabilized at(78.42±3.78)% and (2554.58±132.78)mgTN/(m²·d), respectively. The activity of PDB remained consistently higher than that of AnAOB, reaching stabilization levels of (6495.85±627.61) and (3093.15±43.91) mgN/(m²·d), respectively. High-throughput sequencing revealed significant enrichment of PDB (Thauera, Denitratisoma) and AnAOB (Ca. Brocadia, Ca. Jettenia), with their relative abundances being 5.33%, 8.32%, 13.57%, and 0.29%, respectively. Fluorescence in situ hybridization (FISH) analysis indicated that AnAOB predominantly colonized the outer layer of the biofilm, suggesting a chemotactic migration behavior. Partial least squares path modeling (PLS-PM) analysis showed that operational conditions directly influenced microbial community succession, which, in turn, indirectly affected the nitrogen removal performance of the system. This study offers valuable theoretical insights and engineering references for the rapid startup and stable operation of PD/A systems.

The migration and retention of light non-aqueous phase liquid (LNAPL) in fractured vadose zone is a complex multiphase seepage process, involving interactions among LNAPL, water, and air. To reveal the influence of entrapped water on LNAPL migration in fractures, comparative experiments on LNAPL migration in dry and water-entrapped fractures were conducted using a transparent fracture model. By combining image acquisition and processing techniques, the migration processes and retention characteristics of LNAPL in the experiments were obtained. The results showed that in dry fractures (under two-phase seepage conditions), LNAPL moved in the form of finger flow; however, in water-entrapped fractures (under three-phase seepage conditions), LNAPL moved in the form of film flow along the edges of water droplets. Compared with finger flow, the flow channel of film flow was more tortuous and the expansion range was wider, resulting in a larger retention volume of LNAPL in the fracture. The influence strength of film flow depended on the amount and distribution characteristics of water entrapped in the fracture, which were related to the fracture inclination angle. When the fracture tended to be horizontal, the migration range of LNAPL was the largest, and the residual amount was the greatest, whereas this effect was the weakest when the fracture tended to be vertical. Additionally, it was found that the fracture apertures of LNAPL residual zones in both dry and water-entrapped fractures followed a normal distribution. However, under water-entrapped conditions, the fracture aperture corresponding to the maximum LNAPL residual amount was larger than that under dry conditions, and it was mainly concentrated in the range of 0.3~0.4mm.

This study evaluated the electrochemical performance of organic oxidation and anode-derived gas reduction through electrochemical measurements, gas chromatography (GC) tests, and experiments on in-situ CO₂ reduction coupled with organic oxidation, and systematically analyzed the mechanisms by which key factors influenced the synergistic system. Electrochemical tests revealed that the Pt electrode exhibited optimal catalytic activity for glycerol (C₃H₈O₃) in a 0.1mol/L Na₂SO₄ electrolyte, and anodically generated CO₂ could be efficiently reduced at the cathode. Synergistic experimental results showed that at a Na₂SO₄ concentration of 0.1mol/L and a cathode potential of -1.8V (vs. SCE), the CO₂ produced by anodic oxidation was converted to formic acid with maximum efficiency, achieving a carbon utilization efficiency (U_c) of 79.24%. The specific electrical energy consumption for formic acid production in the synergistic system decreased by 45.6%, and relative to the separate systems for electrocatalytic oxidation of C₃H₈O₃ and CO₂ reduction, the overall energy consumption was 65% lower. Analysis of the results indicated that operational parameters regulated the selectivity of anodic and cathodic reactions by modulating the current density and the supply of CO₂ and H⁺.

Through comprehensive systematic surveys of algal accumulation layers along the shores of Dianchi Lake during summer and autumn, coupled with studies on the release flux of endogenous pollutants within the lake, this research aims to clarify the sedimentation characteristics of algae in Dianchi Lake and their contribution to endogenous pollution loads. Based on systematic surveys of 24 lake-wide cross-sections and 96 profile characteristics, it was found that the residual algal biomass in Dianchi Lake sediments gradually decreases from north to south. The storage volume in the eastern outer lake area is significantly higher than that in the western area, and this trend aligns with the spatial distribution heterogeneity of cyanobacterial blooms in Dianchi Lake over the years. The overall distribution pattern across the lake's littoral zone was: Central Outer Lake (577.92ng/g) > Northern Outer Lake (521.32ng/g) > Caohai (276.55ng/g) > Southern Outer Lake (240.05ng/g). The thickness of the algal layer in Dianchi Lake generally ranged between 5and 10cm. The 0~10cm depth zone (representing the fresh algal detritus settling and accumulation area) accounted for approximately 27% of the total thickness, while the 10~15cm depth zone contributed over 25%. No significant differences were observed in surface, middle, and bottom layer chlorophyll a concentrations between Caohai and the northern Outer Lake. This correlates closely with the resuspension of surface floc in Caohai and the year-round wind-wave disturbance causing sediment resuspension in the northern Outer Lake. Preliminary calculations indicate Caohai sediment algal biomass at 3.65g/m², contributing 26.4t and 2.5t of algal-derived nitrogen and phosphorus, respectively. In the outer lake, the biomass was 6.43g/m², contributing 46.6t and 4.5t of algal-derived nitrogen and phosphorus from the sediment, respectively. At the sediment-water interface, the average release rate of SRP was 2.45mg/(m²·d), and the average release rate of NH₄⁺-N was 138.21mg/(m²·d), both dominated by release processes. SRP and NH₄⁺-N release rates in the northern and central coastal waters of the outer lake were higher than those in Caohai and the southern outer lake, closely aligning with algal accumulation layer distribution characteristics. This may serve as primary evidence that algal-derived nitrogen and phosphorus in Dianchi Lake profoundly influence sediment nitrogen and phosphorus release. Furthermore, analysis revealed a significant positive correlation between Chla content in Dianchi sediment and SRP/NH₄⁺-N release rates. The risk of endogenous release from Dianchi Lake sediments exhibits spatial variation, being higher in the north and lower in the south. The northern Outer Lake (high algal deposition and strong disturbance) and central Outer Lake (high algal deposition) are high-risk zones for endogenous nitrogen and phosphorus release, characterized by relatively poorer overall water quality. The release of algal-derived nitrogen and phosphorus from buried sediments is one of the primary contributing factors. The southern parts of Caohai and the outer lake currently exhibit lower risks but still require enhanced management and monitoring. As a critical component of endogenous pollution control, managing the enrichment and release risks of algal-derived nitrogen and phosphorus in sediments will be a key focus for future endogenous pollution control in Dianchi Lake.

Through quantitative analysis of major multi-class dominant coexisting components in municipal tailwater, this study conducted comparative experiments to examine the differences in the rejection selectivity behavior of a self-made heterogeneous polyamide nanofiltration (NF) membrane towards three typical trace-level pharmaceutical active compounds (PhACs), under conditions with and without the influence of solute-solute affinity interactions. Building on this foundation, the existence forms and partitioning characteristics of target PhACs in the presence of the complex environmental matrix of municipal tailwater were further explored, revealing the size and hydrophilic/hydrophobic effects of bounded PhACs. The results demonstrated that the co-existing components enhanced the water/diclofenac selectivity of the piperidine-doped NF membrane by 1.15 orders of magnitude. Characterizations based on apparent hydrodynamic diameter, absorbance ratio and fluorescence spectroscopy collectively provided robust evidences for the occurrence of solute-solute micro-interfacial affinity interactions between target PhACs and the dominant co-existing components. The percentage of bounded PhACs ranged from 71.2% to 96.3%. Furthermore, the study observed a positive correlation between the molecular weights of bounded-PhACs and their hydrophobicity. Besides, the expression of dominant hydrophobic fractions was found to be closely associated with the dissociation tendency and strength of PhACs in environmental water bodies.

Eutrophication-induced algal blooms significantly disrupt the stability of aquatic ecosystems. Micro-nano bubbles (MNBs), which generate reactive oxygen species (ROS) upon self-collapse, exhibit strong oxidative capability and hold great promise for water pollution control. This study investigates the patterns and impact factors of ROS generation by MNBs under various environmental conditions, and further explores the role of ROS in the degradation of Chlorella. The results demonstrate that higher gas flow rates, longer aeration times, and greater water depths favor the generation of ROS, with hydroxyl radicals (·OH) identified as the primary active species. Degradation experiments reveal that, compared to conventional ozone bubbles (O₃), O₃-MNBs produce a higher yield of ROS, which further induce oxidative damage to the Chlorella cell membrane, leading to accelerated leakage of intracellular proteins and nucleic acids, and ultimately causing cell lysis. ROS inhibition studies confirm that ·OH is the key driver of cell membrane damage in Chlorella. This study provides insights into the generation mechanisms of ROS by MNBs, elucidates their roles in algal inactivation, and offers valuable theoretical support for the management of eutrophic water bodies.

A parametric stirring optimization framework was established using computational fluid dynamics (CFD) simulations to systematically investigate the effects and mechanisms of mechanical-pneumatic synergistic stirring on the mixing and mass transfer characteristics of high-solid anaerobic digesters. This framework integrated a power-law model to describe the rheological behavior of the material, a multiphase flow model, and quantitative optimization criteria. Utilizing a typical high-solid concentration (TS=15%) as a specific case, single-phase and multiphase numerical models were developed to quantitatively evaluate the flow field distribution under four types of impellers (double-pitched blade turbine, disk turbine, anchor, and single helical ribbon) and three rotational speeds (20.00, 60.00, and 100.00r/min). The results indicated that the dead zone volume was reduced by 81.49% with the single helical ribbon impeller at 60.00r/min, while the average liquid-phase shear stress (4.42Pa) remained below the microbial floc destruction threshold of 5.00Pa. Furthermore, when inclined gas jet stirring was coupled, a nozzle inclination angle of 30° was found to increase the gas holdup to 24.20%, representing a 4.27-fold improvement over vertical jetting. The nozzle orifice diameter was optimized to 10.00mm to achieve synergistic control over the high-speed liquid-phase region ratio and bubble number density. Ultimately, a bottom-symmetric dual-nozzle-single helical ribbon impeller synergistic stirring system was constructed, which increased the mixing uniformity index by 14.75% and reduced energy consumption by 28.95%. Based on the successful application and flow field analysis of the TS=15% system, quantitative criteria for matching microbial activity maintenance with fluid dynamics optimization were established. This parameterized CFD framework can be extended to evaluate mixing effects in systems with varying solid content by incorporating material-specific rheological parameters, providing a universal optimization method and a theoretical foundation for the design of high-solid anaerobic digestion reactors.

Hydrothermal treatment was applied to municipal sludge to investigate the speciation distribution of heavy metals and phosphorus in solid and liquid phases. The migration behavior and ecological risks of heavy metals were analyzed using the improved European Community Bureau of Reference (BCR) sequential extraction method combined with leaching toxicity assessment, while phosphorus transformation in hydrochar was examined by modified Hedley fractionation. Results indicated that most heavy metals were enriched in hydrochar and converted into more stable forms, with the ecological risk index decreasing to below 30%. Phosphorus was concentrated in hydrochar with an enrichment efficiency exceeding 90%, and its speciation shifted predominantly from NaOH-extractable phosphorus (NaOH-P) to HCl-extractable phosphorus (HCl-P) and residual phosphorus (Res-P), indicating enhanced stability. In conclusion, hydrothermal treatment achieved co-enrichment of heavy metals and phosphorus in hydrochar, simultaneously reducing the ecological risk of heavy metals and the leaching risk of phosphorus. These findings provide a theoretical basis for the stabilization treatment of municipal sludge.

Data-driven intelligent identification technologies for hazardous waste (medical waste) were systematically reviewed. General principles for modeling based on artificial intelligence and spectroscopy were summarized. Key challenges, including data acquisition, class imbalance, model generalization, and interpretability, were analyzed. Future research directions were proposed, including AI-assisted spectroscopic modeling, transfer learning, multimodal data fusion, and machine-learning-based modeling of relationships among spectra, structures, and properties. A systematic reference for the intelligent identification and management of hazardous (medical) waste was provided, and guidance to accelerate practical deployment in treatment and disposal, resource recovery, and intelligent monitoring was offered.

The synergistic treatment of municipal sludge with black soldier fly larvae (BSFL) and its effects on nitrogen transformation were investigated in this study. Sludge-based substrates with 0%, 10%, and 30% wheat bran (T2~T4) were used for BSFL treatment, with T1serving as the BSFL-free control. BSFL performance, bioconversion efficiency, and nitrogen transformation characteristics during the sludge treatment were systematically evaluated. Results indicated that the combined application of BSFL and wheat bran significantly enhanced biotransformation efficiency (20.13%~35.24%), alongside increases in crude fat (19.69%~ 26.77%) and protein content (16.26%~24.26%). The best growth performance and nutrient accumulation were observed in the treatment group (T4) with a 30% addition of wheat bran. Moreover, a notable reduction in substrate moisture (7.49%~7.65%), organic matter (16.33%~28.50%), and dissolved organic carbon (DOC) (25.53%~47.06%) were achieved, while pH (8.42~8.63) and electrical conductivity (635~1110μS/cm) were increased by BSFL treatment. Analysis of nitrogen fractions revealed that substrate organic nitrogen degradation was significantly accelerated by BSFL, thereby promoting the ammonification process. A 36.45%~51.09% reduction in total nitrogen (TN) was measured in the post-treatment sludge, accompanied by a marked increase in NH₄⁺-N, and consistently low NO₃^--N levels. Redundancy analysis (RDA) revealed that urease activity was positively correlated with NH₄⁺-N, EC, and pH, suggesting that urease and dehydrogenase activities were regulated by BSFL to facilitate the conversion of organic to inorganic nitrogen forms. Furthermore, protease activity exhibited a close relationship with organic matter content, gradually diminishing as substrate availability decreased. These findings demonstrate that BSFL enhance carbon-nitrogen metabolism by modulating key hydrolytic enzymes, thereby optimizing nitrogen transformation pathways in sludge.

Surface and subsurface soils collected from a bamboo forest at the footslope of an upland were used to explore the effects of pig manure dissolved organic (PM DOM) and its hydrophilic (HI) and hydrophobic (HO) fractions on the adsorption, transport, and retention of doxycycline, enrofloxacin, florfenicol, and sulfamethazine. Total DOM was extracted from pig manure and further separated into HI and HO fractions using XAD-8resin column. According to the results of batch equilibrium experiments, the addition of PM DOM led to varying decreases in the adsorption of enrofloxacin, florfenicol, and sulfamethazine but marked increases in the adsorption of doxycycline; the addition of PM DOM's HIS fraction substantially weakened the adsorption of enrofloxacin and florfenicol by the soils; the addition of PM DOM's HO fraction significantly enhanced the adsorption of doxycycline but markedly reduced the adsorption of florfenicol by the soils. According to the results of saturated transport experiments in repacked soil columns, doxycycline and enrofloxacin could make a breakthrough; the HI fraction of PM DOM played a predominant role in reducing the recovery rate of sulfamethazine in the surface and subsurface soils (by 13.6% and 5.4%, respectively), while both the HI and HO fractions of PM DOM increased the recovery rate of florfenicol (only evidenced in the surface soil; by 30.7% and 20.1%, respectively). The addition of PM DOM could enhance the retention of sulfamethazine and florfenicol (by 14.9% and 7.8%, respectively, in the surface soil columns; by 3.1% and 10.6%, respectively, in the subsurface soil columns) while promote the redistribution of enrofloxacin and doxycycline to deeper soil layers. The humification degree and aromaticity of DOM in the aqueous phase of the soils, as well as the content and proportion of humic-like and protein-like components of DOM, might exert a crucial influence on the transport of veterinary drugs in the soils.

To evaluate the effects of brackish-water deficit irrigation combined with microbial fertilizer on soil salinization, microbial community structure, and predicted functions, a field experiment was conducted on moderately saline-alkaline soils in the Hetao Irrigation District using Lycium barbarum as the indicator crop. Brackish water irrigation depths were set under microbial fertilizer application (W1: 180mm, W2: 240mm, W3: 300mm, CK: 330mm). It was found that, compared with CK, total soil salinity under W2 was reduced by 56.77% from the fruit expansion to defoliation stages, and Na⁺ was reduced by 55.87% (excluding the flowering stage). During critical yield-formation stages, K⁺, Ca²⁺ and Mg²⁺ were decreased by 45.29%~78.28%. The sodium adsorption ratio (SAR) was decreased by 33.65% and 54.23% at the fruit expansion and leaf drop stages, respectively. In early growth stage, soil pH was increased by 3.63% under W1(P<0.05), whereas no significant differences among treatments were detected thereafter (P>0.05). The bacterial community was dominated by Proteobacteria, Bacteroidetes, Actinobacteria, and Acidobacteria, with Sphingomonas and Pseudomonas as predominant genera. Under W2, the relative abundance of Acidobacteria was increased by 28.09% (P<0.05), and during the fruit expansion stage the relative abundance of Sphingomonas was significantly higher than under CK; this genus was significantly negatively with Cl^- content (P<0.05) and SAR value (P<0.01). Under brackish water irrigation, Bacillus amyloliquefaciens was selectively enriched under W2 (57.6% relative to CK; P<0.05), and accumulation of Paenibacillus mucilaginosus at the peak fruiting stage was promoted; enrichment of both taxa was maintained through defoliation.Functional prediction indicated that chemoheterotrophy and aerobic chemoheterotrophy were the primary community functions, and the abundances of carbon- and nitrogen-cycling functional groups were increased by 8.25% and 36.31%, respectively, under deficit brackish-water irrigation. Redundancy analysis (RDA) indicated that K⁺, Mg²⁺, Cl^-, and Na⁺ were the key drivers of microbial community variation, with a cumulative explanatory rate of 54.65%. The soil quality index (SQI) based on principal component analysis (PCA) indicated stage-dependent irrigation demand: at the flowering stage, W3increased SQI by 14.46%, whereas from the fruit expansion to defoliation, SQI under the W2 increased by 381.11%. On the basis of the SQI-irrigation volume model, an optimal brackish-water irrigation depth of 240~260mm under microbial fertilizer application was proposed.

Pakchoi pot experiment was carried out with polyethylene microplastics (PE-MPs) and lambda-cyhalothrin. The Illumina NovaSeq high-throughput sequencing technology was employed to sequence and analyze the soil bacterial communities on the 1st and 30th days of the experiment. The results demonstrated that PE-MPs significantly inhibited the root length, fresh weight, and plant height of Pakchoi (P<0.05), which were reduced by 39.63%, 32.9%, and 19.54%, respectively, compared to the control. In contrast, lambda-cyhalothrin promoted plant growth, and when applied in combination, it alleviated the inhibitory effects of PE-MPs. On the 1st day of the experiment, both lambda-cyhalothrin and PE-MPs significantly affected the diversity of the bacterial community (P<0.05) and inhibited the growth of some bacterial groups. As the experiment progressed, lambda-cyhalothrin mitigated the inhibitory effect of PE-MPs pollutants on bacterial groups. LEfSe analysis revealed that the indicator bacterial taxa in different treatment groups varied at different times. FAPROTAX functional prediction analysis indicated that, compared to the control, lambda-cyhalothrin may inhibit the abundance of functional groups related to hydrocarbon degradation on both day 1and day 30, while PE-MPs may significantly promote their abundance. However, this promotional effect was attenuated under combined treatment. Lambda-cyhalothrin may significantly increase the abundance of human pathogen-related functional groups, especially at the beginning of the experiment. Interaction network analysis of the top 30 genera in terms of abundance indicated that PE-MPs promoted the symbiotic and cooperative relationships among these genera in terms of abundance at the end of the experiment (day 30), while the combined pollution significantly enhanced such relationships at the beginning of the experiment (day 1). These findings provide a scientific basis for a deeper understanding of the impacts of PE-MPs and lambda-cyhalothrin pollution on the microecological environment of farmland soil.

This study systematically investigated the adsorption mechanisms of heavy metal Tl by layered double hydroxide (LDH). For the first time, CaAl-LDH was applied to immobilize Tl in three typical Tl-contaminated soils-red soil, yellow soil, and black soil. The immobilization effectiveness was assessed based on the ecological and health risks associated with soil Tl, using the Tessier sequential extraction method and an in vitro test method. Results showed that the active sites on CaAl-LDH surface were uniformly distributed, with Tl⁺ adsorption primarily following monolayer adsorption behavior, consistent with the Langmuir model. The key adsorption mechanisms included: (1) synergistic adsorption induced by anion exchange in LDH interlayers; (2) surface adsorption of Tl⁺ on LDH lamella surfaces and edges; and (3) complexation with Tl⁺ following the release of functional groups from the LDH surface. At the relative optimal application rate (5% of soil mass), CaAl-LDH significantly reduced the mobility factor of soil Tl and the relevant ecological risk and crop uptake risk, with an average decrease of 24.1%. Also, it significantly lowered the bioaccessibility of soil Tl and the relevant human health risk, with an average decrease of 30.5% in the gastric phase and 21.3% in the small intestinal phase. These findings provide a scientific foundation and practical reference for developing immobilizing remediation agents for Tl-contaminated soils, thereby contributing to improved soil environmental quality and human health protection.

Based on the InVEST model and integrating the use of the Geodetector and Geographically Weighted Regression (GWR) model, this paper dynamically analyzed the spatio-temporal evolution characteristics and driving mechanisms of habitat quality in Gannan Prefecture at the county scale from 2000 to 2020. The results show that: 1) From 2000 to 2020, habitat quality continuously deteriorated, with an average annual decline rate of 0.0016a^-1. The spatial distribution was relatively stable, showing a pattern of high in the southwest and low in the northwest-southeast. Hotspots were concentrated in Maqu County and Luqu County, while coldspots were distributed in a band or patch form around towns and in areas with dense road networks, mainly consisting of construction land and cultivated land. 2) The mutual conversion of land use types had a negative impact on habitat quality, with a cumulative decline of 0.031 in the habitat quality index. The conversion from forest land and cultivated land to grassland and from cultivated land to forest land were the main types that improved habitat quality. However, the conversion from ecological land to living and production land and from grassland to cultivated land was continuously expanding, with an average annual conversion area of 20.22 and 194.05km² respectively, further intensifying the risk of habitat degradation. 3) Elevation (0.459), average annual temperature (0.433), average annual precipitation (0.349), average annual evaporation (0.345), GDP (0.274), and population (0.269) were the main driving factors of habitat quality differentiation, and the interaction between these factors was nonlinearly enhanced or double-factor enhanced. The interaction between elevation and other factors was the strongest, with a contribution rate of over 45%, which had a decisive influence on the spatial distribution of habitat quality. 4) The impact of different factors on habitat quality in space was significantly different (P < 0.05). Average annual temperature, average annual evaporation, GDP, and population mainly had negative effects on habitat quality, while elevation and precipitation had significant positive effects. Below 3200m, habitat quality was relatively low, ranging from 0.045 to 0.203, with severe degradation fluctuating between 0.146 and 0.232. Above 3200m, precipitation was abundant and habitat quality was relatively high (0.383~0.759), but this area was more sensitive to climate change, with low grassland continuity and point-like habitat degradation. In future environmental protection, strict control over the expansion of construction land should be implemented, the system of land use control for cultivated land should be strictly enforced, and differentiated and diversified regulatory strategies should be adopted considering the characteristics of different driving factors. At the same time, attention should be paid to the impact of climate change on habitat quality in high-altitude areas, and through refined regulation of the human-land relationship and strategies to address climate change, the overall quality and efficiency of habitat should be improved.

This study established an integrated SWAT-LSTM-MLP model to investigate phosphorus flux dynamics in the Baiyangdian Basin, China. The SWAT simulations revealed three key findings: (1) the average annual phosphorus input of the basin was 717.3t/a(57.6kg/km²·a) during 2019~2023, and the organic phosphorus (78.8%) was the main form, which showd an increasing trend in 2023; (2) the phosphorus flux showed significantly seasonal variation, the flood seasons (June-September) accounted for 85.57% of annual phosphorus loading (49.28kg/km²), which was significantly positive correlations (P<0.01) with precipitation, runoff, and sediment load; (3) for the spatial distribution, the phosphorous load of Fu-Cao-Pu River (79.3kg/km², 32.09%) and Baigou Diversion Canal (66.6kg/km², 26.96%) was higher than other region. Furthermore, in order to avoid the deficiency of the SWAT mobile in nonlinear varaitions, the LSTM-MLP hybrid model was applied to improve the accuracy of phosphorous load prediction. The model results showed that:(1) the LSTM-MLP hybrid model significantly improved prediction accuracy (NSE>0.9, RMSE<4kg/km²) compared to conventional LSTM (NSE>0.8, RMSE<7kg/km²), particularly in capturing peak values; (2) simulate analysis under different sediment reduction scenario demonstrated that the Baigou Diversion Canal under 60% sediment reduction scenario can reduce 35.29% of phosphorus load, which was the most effective regions among all subregions.

This paper revealed the spatial and temporal distribution and source characteristics of dissolved organic nitrogen (DON) in the watershed through the joint analysis of water quality indicators, three-dimensional fluorescence spectroscopy (3DEEM) and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The results showed that the proportion of DON concentration to total dissolved nitrogen concentration in all counties of the watershed in all seasons ranged from 15% to 20%. The overall DON level was low, while the DON/TN ratios in the main stream sections of the two downstream counties were significantly higher than those in the upstream. 3DEEM showed that DOM was dominated by humus of terrestrial origin, and the activity of the protein-like fractions was enhanced in summer and autumn. The fluorescence index indicated that agricultural input dominated the exogenous pollution. FT-ICR MS detected that nitrogenous organic matter was dominated by lignin-like substances. The input of Yellow Water (YH) elevated the percentage of condensed aromatics downstream by 11.4%. The lower amount of nitrogenous organic matter in the water body in summer compared with autumn at Gaojiaxie Village (G9) revealed the influence of land-source humus input. The transformation of dissolved organic nitrogen in the Fen River basin was synergistically driven by exogenous inputs, biodegradation and photolysis, which formed the characteristics of DON sources under the action of multiple mechanisms. The study suggested that priority should be given to the control of tributary inputs of difficult-to-degrade organics to enhance the effectiveness of management.

To investigate the pollution sources of heavy metal elements and assess the health risk status in the water of South Dongting Lake, and to provide data and methodological support for the precise prevention and control of heavy metal pollution and public health management, a total of 24 surface water samples and 16 groundwater samples were collected in the area. The absolute principal component score-multiple linear regression (APCS-MLR) receptor model and the health risk assessment (HRA) model were applied to analyze and evaluate the contamination sources of eight heavy metals (As, Co, Cr, Mn, Ni, Pb, Zn, Cd) and their associated health risks in the water bodies of South Dongting Lake. The results revealed considerable variation in heavy metal concentrations. In surface water, only Cr exceeded the standard, with an exceedance rate of 33.33% and an average concentration 4.70 times the standard limit. In groundwater, Cr and Mn exceeded the standards, with exceedance rates of 25.00% and 31.25%, and average concentrations 1.32 and 3.07 times their limits, respectively. The remaining elements complied with the relevant quality standards. Most heavy metals showed significant spatial variation, and Cr contributed the most to the total heavy metal concentration in both water bodies. Based on the single-factor and Nemerow pollution indices, Cr in surface water was at a severe pollution level, while Mn and Cr in groundwater were at severe and moderate levels, respectively; however, the overall pollution level of the regional water bodies was relatively light, with good water quality. Pollution source apportionment identified four primary sources: agricultural activities (29.76%), industrial activities (26.78%), natural geological background (23.57%), and traffic-related sources (19.90%). The health risk assessment indicated that risks from the drinking pathway were greater than those from dermal contact, and adults faced higher risks than children. The combined non-carcinogenic risk for adults was primarily attributed to Cr and Zn via the drinking water pathway. The carcinogenic risk of Cr posed a potential threat to both groups through drinking. Furthermore, Cr originating from industrial and agricultural activities was identified as the major contributor to carcinogenic risk. Therefore, to ensure the environmental safety of the water in South Dongting Lake, it was concluded that pollution sources should be strictly controlled, and the supervision and management of heavy metal pollution risks in the water bodies should be continuously strengthened, with priority given to controlling heavy metal pollution caused by industrial activities and agricultural production.

This study focuses on the phenological changes of Stipa krylovii steppe in Inner Mongolia and their responses to the maximum and the minimum air temperature, based on MODIS NDVI data and corresponding ground-based phenological observations from 2000 to 2024. The HANTS method was employed to reconstruct NDVI time series, and the start of season (SOS) and the end of season (EOS) were obtained using a dynamic threshold method. The results showed that: (1) the thresholds of 50% for SOS and 65% for EOS resulted in the lowest extraction errors, with RMSE values of 8d and 11d, respectively; (2) from 2000to 2024, the SOS advanced at a rate of 0.32d/10a, while the EOS was delayed at a rate of 0.12d/10a, indicating a prolonged growing season; (3) the EOS was more sensitive to air temperature than the SOS, the daytime mean maximum temperature had a significantly stronger advancing effect on EOS than the nighttime mean minimum temperature. This study determined the remote sensing-based optimal thresholds of Stipa krylovii steppe phenology, revealed the effect of air temperature on phenological change, and provided a scientific basis for steppe management under climate change.

Based on the the ecological footprint model, this paper analyze the characteristics of natural capital utilization and comprehensive ecological security situation in CPUA from 2010 to 2021. The weighted Voronoi diagram was used for ecological security zoning, and partial least squares regression was employed to identify the main driving factors. The results revealed that: (1) the per capita ecological footprint (ef) of CPUA increased by 11.27%, while the per capita ecological carrying capacity (ec) remained relatively stable. The per capita ecological footprint size (EF_size) ranged from 0.289~0.300hm²/cap, whereas the ecological footprint depth (EF_depth) ranged between 2.595~2.928 and maintain an upward trend. (2) The ecological pressure index, ecological coordination index, stock-flow usage ratio, and ecological footprint diversity index demonstrated a gradual decline in ecological security situation. The improvement of ecological utilization efficiency contained the trend of ecological deterioration effectively. The comprehensive ecological security index was generally in a "medium insecurity" state. (3) Based on the weighted Voronoi diagram, the CPUA was divided into central core development zone, western transformation development zone, northern optimization development zone, eastern protection development zone, and southern green development zone. (4) The proportion of primary industry output value and the total energy consumption were important positive driving factors in most regions, while the influence of other factors on ecological security varied significantly in different regions.

An investigation was conducted to examine the influence of runoff input on the water quality of stratified reservoirs and to identify optimal artificial control strategies for positioning the intrusive layer, so as to enable the withdrawal of high-quality water. High-frequency and comprehensive in-situ monitoring of water quality indicators for spring snowmelt and summer storm runoff was conducted at Lijiahe reservoir (LJHR) in the northern foothills of the Qinling Mountains, to analyze the pollution characteristics, intrusive layer, and reservoir water quality response mechanisms. The results indicated that ① nitrogen/phosphorus (N/P) concentrations in runoff were significantly higher than those in baseflow, with snowmelt runoff was dominated by dissolved nutrients, while storm runoff contained dissolved N but particulate P. Moreover, N/P concentrations in storm runoff were significantly greater than those in snowmelt, which was attributed to differences in discharge. ② The effects of suspended solid (SS < kg/m³) on water density was neglected in the three runoffs events, and three different intrusive layers can be formed based on the differences between the runoff water temperature and the surface and bottom water temperatures of the reservoir. The water temperature of snowmelt runoff was typically higher than that of the reservoir bottom layer, leading to the development of overflows. Additionally, the abundance of available nutrients and the stable water environment during the early stages of reservoir stratification promoted rapid algal growth in the surface layer, which could easily induce algal blooms. ③ Prior to storm runoff inflow, the Water-lifting aerators system (WLAs) was used to regulate the intrusive layer of runoff seepage by modifying the vertical thermal structure of the reservoir. During the July torrential rain event, intermittent operation of the WLA resulted in higher water temperatures in the storm runoff [(18.46 ± 0.76)℃] compared to the bottom layer (16.67℃), leading to the formation of an interflow (837.9~815.6m). In September, continuous operation of the WLA raised the bottom water temperature to 19℃ before the storm inflow, which was higher than that of the incoming runoff [(12.35±0.59)℃], thereby inducing an underflow (800~828.2m). ④ Nutrient concentrations were significantly elevated in the intrusive layer, the formation of underflow induced by WLA placed the intrusive layer below the intake elevation (832m), effectively mitigating the impact of high-pollution-load runoff on water supply quality. Additionally, the compression of the intrusive layer reduces its thickness, thereby shortening the duration of its effects on water quality. This study provides a practical engineering reference for ensuring the safety of reservoir water supply. It is recommended activating the WLA at the early stages of reservoir stratification to inhibit algal blooms caused by snowmelt runoff and to increase the reservoir bottom water temperature above that of the runoff, thereby inducing the formation of underflow from runoff to achieve "high-quality mid-level water intake" during the storge period while ensuring "turbidity reduction and water clarity" during peak floods events.

This study focused on the coal-grain overlapping areas of the Huaihe River Basin, analyzing 31 water samples through integrated EEMs-PARAFAC and FT-ICR MS techniques to unravel DOM molecular signatures and transformation pathways under intense anthropogenic disturbances. Key findings include: (1) PARAFAC identified three fluorescent components (C1: UV humic-like; C2: terrestrial humic acid; C3: tryptophan-like), where intensity distribution (C1 > C3 > C2) and spectral indices (FI=(1.77 ± 0.12); HIX = (0.73 ± 0.07)) revealed dual DOM origins from terrestrial inputs (agricultural tributaries) and microbial degradation (urbanized mainstream), highlighting their synergistic interactions. (2) FT-ICR MS unveiled a distinct "upstream agriculture-downstream industry" spatial gradient: CHO and CHON molecules dominated agricultural headwaters, while CHOS compounds increased downstream, governed by PAHs oxidative ring-opening and thioether-to-sulfonic-group conversion. (3) DOM in coal-grain overlapping areas exhibited "sulfur/nitrogen-enriched, multi-source coupling" characteristics. Elevated CHON proportions (33%~37%) in tributaries correlated with fertilizer-derived deamination processes, whereas downstream photochemical-metal co-catalysis (Fe²⁺/H₂O₂) triggered radical cleavage of "coal-sulfur" pollutants, generating highly aromatic, low-oxidation-state stable products. These findings elucidate the dual natural-anthropogenic regulatory mechanisms of DOM, providing molecular-level insights for organic pollutant source tracing and non-point source management in the basin.

By constructing a SWAT model, this study simulated the variations in runoff and nitrogen/phosphorus load fluxes at control sections of the Yanjin River Basin in 2023, analyzed the spatiotemporal characteristics of point and non-point source load emissions, and evaluated the applicability of the SWAT model in the karst region of southwestern China. The results show that: during the validation period, the SWAT model achieved R² values of 0.77, 0.82, and 0.84 for runoff, TN, and TP simulations, respectively, with Nash-Sutcliffe efficiency coefficients of 0.77, 0.67, and 0.78, indicating good applicability in typical karst areas. The main emission zones for total nitrogen (TN) were distributed in the central and southwestern parts of the basin, while total phosphorus (TP) emissions were concentrated in the eastern-central and southwestern regions, reflecting spatial differences in land use and industrial activities. Agricultural non-point sources and urban non-point sources were the dominant contributors to TN and TP losses, accounting for 52% and 31.4% of the total losses, respectively. TN and TP emissions during the flood season reached 2.2 and 3 times those of the non-flood season, with significant correlations between nitrogen/phosphorus loss and rainfall intensity. TP loss was more susceptible to heavy rainfall events.

Taking Miluo City as an example, this study constructed a health evaluation system that includes four major landscape functions, and quantitatively analyzed the spatial and temporal characteristics of landscape function health in Miluo City during 2000~2020. In addition, by integrating spatio-temporal trend analysis, spatial heterogeneity assessment, and driver identification methods, the direction of landscape function evolution, distribution characteristics, and the driving factors behind them are further examined. Finally, this study analyzed the spatial and temporal evolution of the "three living spaces" in Miluo City using the SOM clustering algorithm. It was found that the overall landscape functional health of Miluo City showed a small decline from 2000 to 2020, from 0.182 in 2000 to 0.179 in 2020, and the spatial distribution showed that the areas with higher landscape functional health indices were mostly located in the southern and northeastern woodlands. In contrast, areas with rapid urban expansion have relatively poor landscape functional health. The analysis results show that the dominant factor in landscape functional health has gradually shifted from climatic conditions to human activities, with the contribution of human activities increasing from 18.3% in 2000 to 14.8% in 2020. From this trend, it can be seen that the functional health of Miluo City's landscape is more sensitive to changes in human activities in the context of accelerated global urbanization. In view of the distribution characteristics of the "three life spaces" and their changing rules in Miluo City, specific zoning control recommendations are proposed, including measures to strengthen the management of the ecological red line, adjust the mode of urban expansion, and promote the integration of agriculture and ecology.

The physicochemical properties and environmental risks of microplastics-natural organic matter (MPs-NOM) composite pollutants, which are formed by the interaction between MPs and NOM, are complex and variable. Considerable research has been conducted on the hazards of MPs and NOM, as well as strategies for their removal. However, most studies have focused on the trends of the two components in isolation, neglecting the contribution of interfacial interactions and synergistic hazards, which may lead to an underestimation of their environmental risks. Therefore, this review systematically describes the research progress on MPs-NOM composite pollutants in water, focusing on the interactions, environmental hazards, and efficient removal methods. Furthermore, future research directions are proposed from the perspectives of mechanism revelation, risk assessment, and technological innovation. The mechanisms underlying the formation, fate, and removal of MPs-NOM pollutants throughout the entire process should be strengthened to provide a scientific basis for upgrading water treatment technologies aimed at addressing new pollutants.

Layered double hydroxide modified basalt fiber (ZnFe-LDHs-BF) was applied to a constructed wetland system with vertical flow to investigate its performance and mechanisms in enhancing the treatment of antibiotic wastewater. The study involved altering initial concentrations, temperature, and pH to examine the impact on tetracycline adsorption by the modified basalt fiber. Additionally, metagenomic sequencing was used to assess the influence of the modified basalt fiber matrix on microbial communities. The study found that when the initial tetracycline concentration was 100mg/L and temperature was 25℃, after 24-hour reaction, ZnFe-LDHs-BF would have a maximum adsorption capacity of 9.19mg/g for tetracycline, over two times higher than that of traditional matrices. After incorporating ZnFe-LDHs-BF to the reactors, the average removal rates of tetracycline and erythromycin were 83.18% and 79.88%, respectively. They were 2~3 times higher than those observed in reactors with traditional gravel or unmodified basalt fiber, demonstrating enhanced purification capabilities for COD, NH₄⁺-N, and TP. Metagenomic analysis revealed that ZnFe-LDHs-BF enriched the microbial community, particularly Candidatus Promineifilum and Anaerolinea functional bacteria. Additionally, the abundance of tetracycline resistance genes (e.g., tetC, tetG) and erythromycin resistance genes (e.g., ermF, ermB) increased by 1~2 times, thereby enhancing the microbial degradation rate of antibiotics by 2~3 times.

The study was initiated with the Reynolds number (Re), and three types of microplastics—polyethylene (PE), polypropylene (PP), and polystyrene (PS)—were focused on. By employing the Lagrangian method, the longitudinal instantaneous velocity and motion trajectories of microplastics in water were investigated using high-speed camera tracking and Tracker physics software, with Reynolds numbers ranging from 300 to 580 and 580 to 3500, respectively. It was observed that at very low Reynolds numbers, the motion trajectory of microplastics was approximated by a straight horizontal line, with small absolute error and standard deviation. Reynolds number reached or exceeded the critical value (575~580), transition and turbulence caused a significant increase in longitudinal instantaneous velocity. As a result, the original linear paths were deviated from by the microplastics. Overall, a normal distribution was followed by the longitudinal velocity of microplastics in water. Greater deviation from the standard normal distribution was exhibited by PS, along with more uneven instantaneous velocity fluctuations, and its travel distance in the flow direction was found to be harder to predict. In addition, the total travel distance of microplastics was increased by 0.4‰~6‰compared to straight-line motion, due to flow transition and turbulence.

To evaluate the greenhouse gas (GHG) emissions and mitigation potential in the transportation sector of Henan Province, localized vehicle emission factors were calculated based on the COPERT model. A 3km × 3km gridded emission inventory was established using ArcGIS, and the spatiotemporal dynamics of vehicle-related GHG emissions were systematically analyzed. Vehicle ownership in Henan Province from 2025 to 2035 was forecast by combining the Gompertz function with the elasticity coefficient method, and emission trends under multiple policy scenarios were examined. The results showed that total vehicle GHG emissions increased from 140 million tonnes to 160 million tonnes during 2019 to 2023, with an average annual growth rate of 2.9%. Carbon dioxide (CO₂) accounted for more than 98% of total emissions, while light-duty passenger cars and heavy-duty trucks were identified as the primary contributors. Urban road traffic was responsible for 78.8% of total emissions, and high-emission areas were concentrated in core cities such as Zhengzhou and Luoyang, presenting a spatial pattern of central clustering and peripheral diffusion. Under the baseline scenario, total GHG emissions were projected to reach 170 million tonnes by 2035. In contrast, when new energy vehicle promotion, green commuting, and accelerated retirement of aging vehicles were jointly implemented, total emissions were reduced to 70 million tonnes, representing a 58.1% decrease compared with the baseline. These findings provided quantitative evidence to support carbon management and the optimization of mitigation pathways in the transportation sector of Henan Province.

Based on vegetation remote sensing and meteorological data from 2001 to 2020, the spatiotemporal variations and influencing factors of vegetation carbon sequestration capacity(CSC) in the Yangtze River Economic Belt(YREB) were analyzed using trend analysis, coefficient of variation, and second-order partial correlation. Furthermore, the partial derivative method was applied to quantitatively assess the contributions of specific meteorological factors (temperature, precipitation, radiation) and human activities to CSC across different sub-regions of the YREB. The results showed that: (1) The multi-year average CSC in the YREB was 2505.4gCO₂/m², with an overall fluctuating upward trend and a multi-year average growth rate of 8.9gCO₂/(m²·a). Areas with extremely significant increases (P<0.01) accounted for 25.6% of the region. (2) Significant increased trends in both temperature and precipitation were observed in more than 16.0% of the area, and they were mainly positively correlated with CSC. In contrast, a significant decreased trend in radiation was observed in 6.3% of the area, and it was mainly negatively correlated with CSC. (3) Both meteorological factors and human activities exerted overall positive contributions to CSC (leading to increases in CSC), among which the largest contribution was attributed to human activities (+16.35gCO₂/(m²·a), 86.7%), followed by precipitation (+1.28gCO₂/(m²·a), 6.77%), which contributed positively in the upstream provinces but negatively in the middle and lower reaches. Smaller contributions were attributed to radiation and temperature; a negative contribution of radiation was observed in Guizhou and Shanghai, while positive contributions of temperature were found in all provinces.

This study evaluates the carbon mitigation potential of municipal solid waste (MSW) management strategies in Chengdu by integrating multi-scenario simulations with a refined classification-based accounting framework. The existing system faces compounded challenges, including inadequate source separation, limited source reduction, low resource recovery rates, and a high-emission treatment structure dominated by landfilling and energy-intensive technologies. The results demonstrate that different strategies prevail at distinct stages of the transition. In the short term (2020~2027), a full-incineration strategy reduces net emissions from 4169 to 1314.7kt CO₂-eq, accounting for 95.4% of cumulative reductions. In the midterm (2028~2035), source reduction increasingly alleviates downstream treatment pressure. In the long term (post-2035), system optimization—through improved incineration performance and sludge co-treatment—enhances synergies and carbon sink effects. Among individual strategies, enhanced resource utilization (S4) yields the most immediate mitigation effect, whereas source reduction (S2) generates substantial long-term cumulative benefits. The integrated strategy (S7) outperforms all single-strategy options across most waste categories, underscoring the need for full-chain, coordinated governance. Overall, the findings highlight the importance of differentiated, time-phased, and waste-type-specific policy interventions to enable a low-carbon transition in urban MSW systems.

To investigate the impacts of different freeze-thaw cycles on the pore structure, pore water redistribution and compositional shifts in saline soil, and further reveal the responses of soil microbial carbon emissions, a moderately saline soil from the Hetao Irrigation District in Inner Mongolia, China, was subjected it to 0, 1, 3, 5, 7, and 9simulated freeze-thaw cycles (hereafter termed as CK, FT1, FT3, FT5, FT7, FT9). The CO₂ emission rate was monitored every day (12h freezing + 12h thawing), and the pore water content and major ion concentrations across eight suction levels were determined through high-speed centrifugation. The results showed that: 1) The water-holding capacity of the small pores (size of 0.3~3.5 μm) was significantly higher than that of the large and medium pores (size of 3.5~34μm). After disturbed by freeze-thaw, the soil water-holding capacity decreased significantly, and the water content at the lower suction levels (0~1053cm) of the FT5 group dropped to 18.9%, which was 5.4% lower than the CK group. The total dissolved solids (TDS) content in the small pores reached 75673mg/L for the FT3 group, whilst that in the large and medium pores was only 46955mg/L for the FT5 group. Furthermore, multiple freeze-thaw cycles significantly promoted the soil CO₂ emission rates. 2)The average pore water content varied between 19.97% and 18.9% at the lower suction levels, but ranged only from 6.992% to 5.402% at the higher suction levels. 3) Limited numbers of freeze-thaw cycles (FT1-FT3) significantly increased the ion concentration in pore water, and the Na⁺ concentration reached a peak of 7353.8mg/L in the FT3 group, which was 64.2% higher than that in the CK group (initial value). However, after five freeze-thaw cycles, the Na⁺ concentration abruptly dropped to 3881.5mg/L in the FT5 group, and then rebounded to 92.1% of the initial value in the FT7-FT9 groups. 4) The soil CO₂ emission rates increased with the freeze-thaw cycles, where the FT9 group released 2.94 times the amount of CO₂ compared to the FT1 group. Post the freeze-thaw disturbances, the soil CO₂ emission rate gradually declined to the levels comparable with the non-freeze-thaw group.

Understanding the distribution characteristics of flux footprint based on the observation of carbon, water, and heat fluxes by the eddy covariance (EC) method is an important research issue. The flux footprint prediction (FFP) model was used to analyze the annual observation data of Chenhu wetland ecosystem in Hubei province in 2022, and the variation of flux contribution of eddy-related system in different time and atmospheric stability conditions was investigated. The results indicated that flux footprints of Chenhu wetland ecosystem exhibited temporal variations, with their spatial distribution corresponding to the prevailing wind directions. The coverage of flux footprints during the growing season exceeded that of the non-growing season, while the range of night-time flux contribution area was larger than that of daytime. The maximum distance in the 90% flux contribution zone was 1300m. Within this source area, the annual flux contribution is: marshland (56.01%) > pond water surfaces (20.44%) > lake water surfaces (9.83%) > hydraulic construction land (3.05%) > inland mudflats (0.42%) > other grassland (0.24%). The contribution of reed marsh and water body to the observation data was more than 80%, confirming the monitoring data were representative.

Both unsuitable temperatures and air pollution increase the health risks of chronic obstructive pulmonary disease (COPD). To evaluate the single-effect effects of temperature, PM_2.5 and O₃, as well as the the interaction effects of temperature and PM_2.5 (or O₃) and the interaction effects of PM_2.5 and O₃, COPD hospital admissions among residents in Tianjin from 2014 to 2019 were collected for quantitative analysis using the generalized additive model. The results indicated that temperature significantly influenced COPD hospitalizations in Tianjin, with the low-temperature effect markedly stronger than the high-temperature effect. Low temperatures exerted a greater impact on females and the elderly. At maximum lag effects, every 10μg/m³ increase in PM_2.5 and O₃ concentrations was associated with 1.23% (95% CI: 0.79%, 1.67%) and 0.90% (95% CI: 0.58%, 1.23%) rise in COPD hospitalization risk, respectively. Interaction analysis revealed synergistic effects between low temperatures and high PM_2.5 levels, as well as between high temperatures and elevated O₃ concentrations.Moreover, at high temperatures, as the concentration of PM₂.5 increases, the risk of hospitalization for COPD caused by O₃ exposure will increase. Given the increasing frequency of extreme weather events, greater attention should be directed to the combined health risks of non-optimal temperatures and air pollution for COPD. Measures such as early warning systems and preemptive interventions are recommended.

Per- and polyfluoroalkyl substances (PFAS) are typical emerging contaminants with persistence, bioaccumulation, and toxicity (PBT) properties. Female e-waste dismantling workers are at heightened risk because of their occupational activities. To characterize exposure patterns and explore the potential of hair as a non-invasive biomarker, we longitudinally evaluated 24 female workers via two sampling rounds separated by three months. Serum and hair samples were analyzed for PFAS concentrations, compositional profiles, and inter-matrix correlations. Twenty-seven PFAS were quantified in serum (median total concentration: 108ng/mL; range: 42.8~228ng/mL), while thirteen PFAS were detected in hair (median total concentration: 6.53ng/g; range: 2.92~37.1ng/g). Perfluorooctanoic acid (PFOA) dominated both matrices, accounting for 47.0% of total PFAS in serum and 39.5% in hair. Positively dose-dependent relationships were observed between contemporaneous serum and hair concentrations for PFOA, perfluorononanoic acid (PFNA), perfluoroundecanoic acid (PFUdA), perfluorooctane sulfonic acid (PFOS), and 6:2 chlorinated polyfluoroalkyl ether sulfonate (6:2Cl-PFESA). When serum levels increased from the 10th to the 75th percentile, corresponding hair concentrations rose by 299.88%, 522.14%, 166.98%, 276.97% and 323.34%, respectively. In contrast, no significant associations were found between current hair PFAS levels and serum levels measured three months earlier. Employment duration and workplace type did not significantly influence PFAS burdens. These results validate hair as a practical, non-invasive matrix for PFAS exposure assessment and provide critical evidence for environmental health risk evaluation in this high-exposure occupational group.

Publicly available transcriptomic datasets from zebrafish exposed to three representative per- and polyfluoroalkyl substances (PFAS)—PFHxS, PFOA, and PFOS—were systematically integrated with behavioral data to elucidate comparative toxic potencies and neurotoxic mechanisms. Transcriptomic point-of-departure (tPOD) modeling identified PFOS as the most potent compound (120-h tPOD = 0.3241μmol/L), followed by PFHxS (0.3735μmol/L) and PFOA (0.4506μmol/L). Developmental stage-dependent increases in PFAS tolerance were observed. Behavioral meta-analysis revealed a characteristic biphasic "stimulation-inhibition" response pattern across all three PFAS, with enhanced locomotor activity at low concentrations and suppression at higher doses. Behavior-anchored transcriptomic profiling demonstrated that PFAS exposure broadly perturbed metabolic homeostasis and neural signaling pathways, with PFOS eliciting more pronounced disruptions in signal transduction and immune regulatory networks. Single-cell transcriptomic analysis further indicated that PFOS substantially altered neuronal subtype composition, suggesting that augmented excitatory synaptic activity may underlie the observed behavioral phenotypes.

In response to the challenges of unclear sources and unknown pathways of cadmium pollution and its traceability in China, the material flow analysis method was employed to construct a cadmium material flow analysis framework covering the entire life cycle from resource extraction to the social economic system and final discharge into the environment. This framework was applied to quantify the flows and stocks of cadmium within China from 2010 to 2020, supported by an uncertainty analysis of the data. The results show that domestic extraction and production is the main source of cadmium input in China, while the proportion of foreign trade in imported cadmium is gradually increasing. Driven by the growth of new energy sectors such as lithium batteries, the use of nickel-cadmium batteries declined rapidly, making PVC heat stabilizers the dominant cadmium-containing product in China.Non-ferrous metal smelting was the largest contributor to cadmium emissions, accounting for over 60% of the total; cadmium emissions peaked in 2013, with cadmium in the form of solid waste accounting for 96.42%, cadmium entering the atmosphere and water accounting for 3.54% and 0.04%. In addition, this study found that the cadmium stock in the socio-economic system is increasing at an average annual growth rate of 27.32%. Over all, the growth trend of cadmium production and demand in China has slowed down significantly,and the composition of input sources remains relatively stable. the pollution caused by the various stages of cadmium production in China mainly enters the environment in the form of solid waste, and the management of cadmium-containing waste should be strengthened. Concurrently, accelerating the development of clean and resource-recycling technologies for end-of-life cadmium products is crucial to mitigating the rapidly growing societal stock.

Using panel data for 31 provinces from 2007 to 2022, this study applied the super-efficiency Slack-Based Measure (SBM) model to measure agricultural water use efficiency under the constraint of decoupling economic growth from water resource consumption. Spatial dynamics were assessed using Moran's I index in ArcGIS, while the Random Forest model was employed to identify key influencing factors and their nonlinear effects. The results showed that China's agricultural water use efficiency exhibited a fluctuating yet overall upward trend, with a spatial distribution pattern characterized by "higher in the east and south, lower in the west and north." The overall pattern was found to demonstrate significant spatial autocorrelation, with spatial agglomeration increasingly strengthened. At the local scale, a clear southeast-northwest differentiation was observed, where hotspots expanded toward the west and south, and cold spots shifted from the north toward the northeast. Economic development level and water resource endowment were identified as having greater impacts on agricultural water use efficiency than technological investment and cropping structure. Specifically, the effects of economic development, technological progress, and capital investment followed a stepwise upward pattern, whereas the influence of water resource endowment displayed a "decline-increase-stabilization" trajectory. Furthermore, provinces dominated by rice and maize cultivation were found to have greater potential for efficiency improvement than those dominated by wheat cultivation. Policy recommendations were proposed, including the promotion of smart irrigation in high-efficiency regions, the enhancement of water-saving infrastructure and optimization of cropping patterns in low-efficiency regions, the sharing of best practices in hotspot areas, and the strengthening of governance and structural adjustment in coldspot regions.

Taking Hunan Province as a typical case area, this paper integrates heterogeneous data such as iron and steel product data and social variable data, and adopts a bottom-up approach to estimate the steel in-use stock in the five end-use sectors, namely, buildings, infrastructure, transportation, machinery and durable goods from 1990 to 2021, and analyzes the driving mechanism by innovatively integrating the IPAT model, the LMDI model, and the multivariate linear regression method. The results of the study show that the steel in-use stock and the steel in-use stock per capita in Hunan Province have increased by 12 times and 10times in the past 32 years, and will reach 260 million tons and 3.6 tons per person respectively in 2021. In terms of the sectoral distribution of the steel in-use stock, the share of construction steel in-use stock reaches more than 56% every year. The density of the steel in-use stock shows regional unevenness, and the spatial heterogeneity shows "core-edge" gradient differentiation, with the high value area of stock density (>240000 t/km²) expanding along the vertical axis. Detection of driving factors shows that population growth, economic development and built-up area are the most important driving factors for the development and change of urban steel in-use stock. It is recommended to guide the industry to expand to the backward areas, give policy support, promote industrial integration and cluster development; accelerate the transformation of low-carbon industry, encourage technology research and development and application, and promote energy substitution; implement environmental protection related systems and mechanisms, and strengthen environmental protection publicity and education.

High-quality economic development resides in technological innovation and industrial carbon productivity. Based on the panel data of 288 prefecture-level cities in China from 2011~2021, this paper measured the level of green technology innovation by the number of granted green invention and utility model patents. It then applied an unexpected output super-efficiency SBM model to calculate urban industrial carbon productivity. The system Generalized Method of Moments and the spatial Durbin model were adopted to explore the impact of green technology innovation on urban industrial carbon productivity and spatial spillover effects. Research indicated that: ①There was a significant spatial correlation between the level of green technology innovation and industrial carbon productivity among cities in China, with high to high class cities concentrated and expanding in scope. ② Green technology innovation boosted urban industrial carbon productivity, to a great extent. Such effect was particularly pronounced in western regions, resource-based cities, and lower-income cities. In these cities, green technology innovation helped enhance productivity more effectively. ③ Under different spatial matrices, the direct effects of green technology innovation on urban industrial carbon productivity were significant, which suggested that such innovation clearly improves local urban industrial carbon productivity. What should be noticed is that, the indirect effect of knowledge spillover phenomenon such as green technology innovation dissemination that relies on face-to-face interaction was only significant under the inverse distance square matrix and economic distance nesting matrix. To some extent, these spillovers were weakened by a siphon effect, which inhibited the productivity gains of surrounding cities. Among the factors considered, geographical and economic distance nesting exerted the strongest influence on how green technology innovation affects industrial carbon productivity. Building upon these insights, the country should break away from the governance mode of "self-reliance" in cities, and build an intercity green collaborative governance system. These measures help ensure that R&D investment is channeled to the most efficient locations, breaking through geographical boundaries to form a regional industrial carbon reduction synergy.

To explore the impact of green technological progress and its bias on the synergy of pollution reduction and carbon emission reduction, this study utilizes panel data of 251prefecture-level cities in China between 2007 and 2021, it employs the EBM model with undesirable outputs and the Malmquist-Luenberger index to measure green technological progress and separate biased technological progress at the city level. Then, after employing the coupling synergy degree model for evaluating the synergy degree of carbon emissions and air pollutants, this paper empirically analyzes the specific influences of green technological progress and its bias on air pollution and carbon emission reduction, as well as the mechanism through which it exerts its influences. According to the research findings: Green technological progress and capital-augmenting labor-saving technological progress can significantly promote the synergy between pollution reduction and carbon reduction, the average effect is 0.023 and 0.005. The promoting effect remains robust after a series of robustness checks and treatments for endogeneity. Green technological progress can promote the synergy between pollution reduction and carbon reduction by increasing the accumulation of human capital, with a mediating effect accounting for 8.7%. Government environmental regulation plays a positive moderating role between human capital and the pollution-carbon reduction synergy, with a moderated mediation index of 0.008. However, capital-augmenting labor-saving technological progress, while improving the synergy, is detrimental to the enhancement of urban human capital. According to the results of the heterogeneity analysis, green technological progress has a stronger promoting effect on the synergy in small and medium-sized cities and in the east of the Hu Line, while in super large cities, very large cities, and large cities, it hampers the synergy between pollution reduction and carbon reduction. Meanwhile, the negative effects are more pronounced in large cities. Capital-augmenting labor-saving technological progress has a stronger promoting effect on the synergy in super large cities, very large cities, and in the west of the Hu Line.

This study constructed a theoretical model to delineate the inherent linkages among TPU, vertical industrial spillovers, and enterprise emission reduction, and empirically examined the spillover effects and underlying mechanisms of TPU changes on enterprise emission reduction using a difference-in-differences model. The study demonstrated that: Every unit increase in the forward spillover effect of TPU reduced the SO₂ emission intensity of downstream enterprise by 28%, and every unit increase in the backward spillover effect reduced the SO₂ emission intensity of upstream enterprise by 16%, This conclusion remained robust after a series of tests; Heterogeneity analysis found that the spillover effect of the decline in TPU on enterprise emission reduction was more significant in domestic-funded enterprise, highly polluting industries, and enterprise in central and western regions; Mechanism analysis showed that the forward spillover of the decline in TPU can affect enterprise emission by stimulating source innovation and improving the energy structure. The backward spillover can affect enterprise emission by promoting the progress of end-of-pipe pollution control technology. Moreover, both forward and backward spillovers can affect enterprise emission by optimizing the factor input structure of enterprise and improving the efficiency of industry resource allocation. The research findings of this paper provided empirical evidence and policy references for facilitating the construction of a new development paradigm and improving the institutional mechanisms for high-standard opening-up.

This study systematically reviewed the history and the art of state of data quality assessment (DQA). DQA was implemented basically based on pedigree matrices and conducted qualitative and quantitative evaluations on the basis of data quality indicators (DQIs). However, there were still such problems as unclear DQIs, inconsistent evaluation methods, and difficulties in quantitative evaluation etc. It was recognized that DQA research needed to be increased, and DQA processes, indicators, and methods suitable for the current data status of carbon footprint evaluation had to be constructed. Additionaly, much attention should be paid to data review and data documentation requirements, so as to provide guarantees for the development China carbon footprint database, as well as the implementation of LCA.