A comparative analysis of air quality in Zhengzhou before and after the Spring Festival from 2020 to 2023 was conducted, and high time-resolution observational data on PM_2.5 chemical components and reactive nitrogen gases were utilized to systematically evaluate the impact of fireworks during the 2023 Spring Festival on PM_2.5 concentrations, its chemical composition, NH₃, and HONO. The results indicate that PM_2.5 concentrations in Zhengzhou around the Spring Festival decreased by 67% from 2020 to 2022. However, following the relaxation of fireworks restrictions in 2023, PM_2.5 concentrations increased by 123% year-on-year, with concentrations during the peak fireworks-burning period surging to 8.7 times those of previous periods. Fireworks contributed to 49.6% of PM_2.5 concentrations during the 7-day Spring Festival holiday, with the most significant increases observed in the concentrations of K⁺, SO₄^2-, and Cl^-. Simultaneously, concentrations of toxic and hazardous heavy metal elements, including Al, V, Cr, Cu, Zn, Ba, and Pb, increased significantly during the fireworks-burning period. Furthermore, NH₃ concentrations reached (18.4 ± 8.9)μg/m³ during this period, 1.7 times higher than during non-festival periods, a change that promoted an increase in aerosol pH values. Additionally, HONO concentrations rose to (1.26 ± 0.83)×10^-9 during fireworks burning, representing an increase of 72.6%. This is likely because fireworks led to elevated atmospheric concentrations of NO, NO₂, particulate matter, and nitrates, which in turn promoted the heterogeneous conversion of NO₂, nitrate photolysis, and homogeneous reactions, thereby facilitating HONO formation.

From August 28 to September 3, 2024, the concentrations of atmospheric pollutants and chemical compositions of PM_2.5 along the Hubei stretch of the Yangtze River were obtained using on aboard instruments. During the mobile survey, the average concentrations of CO, NO₂, O₃, and SO₂ were (0.75 ± 0.22) mg/m³, (19.87 ± 12.77) μg/m³, (74.23 ± 39.22) μg/m³, and (21.98 ± 8.81)μg/m³ respectively, all below China's Grade I Ambient Air Quality Standards. The mean PM_2.5 mass concentration was (35.84 ±12.08) μg/m³, with organic matters being the dominant component ((21.94 ± 7.36)%), followed by SO₄^2-((20.53 ± 10.31)%), NO₃^- ((19.88 ± 12.29)%), and ((12.80 ± 4.70)%). Using the receptor model, four PM_2.5 sources including secondary inorganic aerosols, ship emissions, biomass burning, and industrial emissions were apportioned with contributions of (47.86 ± 6.17)%, (26.61 ± 3.32)%, (18.29 ± 6.57)%, and (8.38 ± 4.68)%, respectively. Comparison between mobile ship-based observations and land-based stationary supersite observations revealed stronger secondary formation over the river surface. By coupling the FLEXPART backward simulation with the PM_2.5 emission inventory, the relative contribution of each grid point in the study area to the PM_2.5 concentration along the mobile monitoring route was calculated and the contribution rate along the Yangtze River was 76.90%, while other regions accounted for 23.10%. FLEXPART forward simulation indicated that the ship emissions exerting greater impacts on the riverine regions than other areas.

Climate change and atmospheric pollution represent two critical environmental challenges facing the world today, and the development of high-accuracy emission inventories serves as the scientific foundation for addressing these challenges. Based on the Web of Science database, this study employs a comprehensive approach integrating scientometric mapping and text mining techniques to systematically analyze the thematic distribution, institutional landscape, and collaborative network characteristics within the global emission inventory research domain. The findings reveal a significant growth trend in publication output over the past decades, with a notable leap cycle of approximately ten years. The research themes encompass 26key topics, including transportation emissions, particulate matter pollution, and climate change mitigation, and span across industrial sectors, emission species, and modeling methodologies, as well as specific processes and impact analyses. Research institutions from China, the United States, France, Germany, and other countries have played leading roles in advancing the field, forming a differentiated and diversified research landscape while establishing international collaboration networks with distinct geographical clustering effects. The analysis demonstrates strong interconnections among research themes, with topics such as particulate matter pollution, air quality modeling, and volatile organic compounds showing significant potential in facilitating knowledge integration across different emission inventories. Future research efforts should prioritize (1) establishing a unified classification system for emission inventories, (2) optimizing emission inventory validation methods, (3) promoting transparency and open access to emission data, and (4) strengthening multinational collaboration and information-sharing mechanisms. These measures are essential for synergistically advancing the scientific foundation and practical application of both air pollutant and greenhouse gas emission inventories.

The size of Pt nanoparticles exerts a significant influence on the catalytic degradation performance of Pt-based supported catalysts for the treatment of volatile organic compounds (VOCs, volatile organic chemicals). Herein, uniform Pt nanoparticles were successfully fabricated via liquid phase reduction method and followed deposited on Al₂O₃ through in-situ growth method. It had to noted that the loaded Pt nanoparticles with different sizes had no effect on the textural properties, morphologies and the dispersion of Pt species, etc. The conversion activity of toluene and ethyl acetate were increased with the decline of Pt nanoparticles size. It could be explained by the enhanced interaction between Pt and Al₂O₃ with the decreased Pt size (18nm vs 6nm). Partial electrons could be transformed from Pt to Al₂O₃ to improve the contents of Pt²⁺(13% vs 36%), in the meantime, the amounts of active oxygen species (O_ads) also increased (32% vs 80%). Fortunately, the synergistic effect between Pt²⁺ and O_ads boosted the redox of Pt/Al₂O₃ as well as the catalytic performance of toluene (216℃ vs 178℃) and ethyl acetate degradation (312℃ vs 258℃). The results will provide theoretical direction for the design of highly active supported Pt-based catalysts.

To improve the stability and methane production efficiency of an anaerobic co-digestion system treating high-load food waste (FW) and waste activated sludge (WAS), a 300-mesh metal mesh dynamic membrane bioreactor (DMBR) and an anaerobic continuous stirred tank reactor (CSTR) were operated in parallel under a high organic loading rate (OLR of 22.8g COD/(L·d)). The long-term performance and microbial community characteristics were compared between continuous and intermittent feeding modes. Results showed that at the same OLR, the continuously fed DMBR achieved a higher methane production rate of (8.86±0.29) L/(L·d) and a methane yield of (407±13) mL/g COD, representing an improvement of approximately 12% over intermittent feeding modes and 22% over the intermittently fed CSTR. It also maintained more stable pH levels and exhibited superior degradation capacity, demonstrating enhanced resistance to organic loading shocks. The dynamic membrane effectively retained and enriched key functional microorganisms, including syntrophic bacteria (Treponema, Lutispora, Syntrophomonas) and hydrogenotrophic methanogens (Methanoculleus). Their relative abundances were significantly higher than those in the conventional CSTR, which considerably accelerated the conversion of organic substrates. However, continuous feeding resulted in a lower membrane flux of 0.0079L/(m²·h) and a more rapid increase in transmembrane pressure (TMP) at 0.98kPa/h. In contrast, intermittent feeding maintained a higher membrane flux of 0.025L/(m²·h), though with slightly lower gas production efficiency. Taking into account overall system performance, including methane yield and operational stability, the DMBR system operated with continuous feeding and intermittent discharge significantly enhances methane conversion efficiency and process stability in high-load FW and WAS co-digestion. This offers an effective intensification strategy for the efficient and stable operation of practical high-load anaerobic co-digestion systems.

The dominant benthic macroinvertebrate species in eutrophic lakes, Branchiurasowerbyi, and polypropylene (PP)-based membrane aerated biofilm reactor (MABR) were selectedin this study, where based oncontrolled microcosm experiments, we explored the effects of benthic bioturbationon dissolved oxygen (DO) concentration in overlying water, DO infiltration depth in the sediments, and the removal of total organic carbon (TOC), nitrogen (NH₄⁺-N, NO₃^--N, NO₂^--N and TN), and phosphorus (PO₄^3--P and TP) by MABR. While the perturbation of B. sowerbyi enhanced Nand Prelease and reduced DO concentrations, the MABR effectively maintained a high level of reoxygenation performance, significantly increasing the DO infiltration depth in the sediments. The removal rates of NH₄⁺-N, TN, and TP remained high at 93.4%, 83.27%, and 90.80%, respectively, demonstrating significant improvements compared to the control group and the B. sowerbyi-only group. Hence, MABR system in removing N and P could effectively cope with the perturbation of B. sowerbyi in eutrophic water bodies.

Traditional up-flow anaerobic sludge blanket (UASB) reactors face challenges such as system acidification, sludge washout, and inferior methanogenic performance during the treatment of actual waste incineration plant leachate. To address these issues, this study constructed a microbial electrolysis cell coupled with a UASB system (MEC-UASB) for treating leachate from waste incineration plants. After 145days of operation, the system demonstrated significantly enhanced performance under an applied voltage of 1V. The COD removal rate of the MEC-UASB effluent reached 80.6%, which was 21.0% higher than that of the UASB control. Moreover, following a sharp increase in COD loading, the attenuation of removal efficiency in the MEC-UASB system was 13.6% lower than that of the control, indicating markedly improved resistance to shock loads. Furthermore, the methane production efficiency of the MEC-UASB system was 1.53 times that of the control, reaching (0.23 ± 0.01) m³CH₄/kg COD. Carbon emission accounting further revealed that the net carbon reduction of the MEC-UASB system reached 10.54kg CO₂/m³, which was 21.9% higher than that of the UASB system. Based on analyses of microbial enzyme activity and community structure, the enhanced performance of the MEC-UASB system was primarily attributed to electrostimulation. This process promoted the enrichment of hydrogenotrophic methanogens, increased the secretion of extracellular polymeric substances (EPS), and enhanced electron transfer efficiency, thereby improving sludge retention and microbial activity. This study demonstrates that the MEC-UASB system resists shock loads robustly under high organic loading conditions, while achieving efficient pollutant removal, significant carbon emission reduction, and economic benefits for long-term stable operation.

In order to investigate the stability of the biological anode-dependent ammonium oxidation process, this study was conducted to explore the operational performances and the associated microbiological characteristics of a microbial fuel cell (MFC) based on biological anode-dependent ammonium oxidation (bioanoammox) under influent carbon-nitrogen ratio (C/N) constraints. The results showed that, the influent C/N could affect microbial community structure in the electroactive biofilm, leading to fluctuation of nitrogen removal and electricity generation in the bioanoammox system. As the influent C/N increased from 0.0 to 3.0, the enrichment of denitrifying bacteria could be achieved in the MFC, resulting that TN removal rates of the system increased due to the coupling of denitrification with bioanoammox. Meanwhile, the synergy of Geobacter with the two functional genera (namely Nitrosomonas and Candidatus Brocadia) also enhanced nitrogen removal and electricity generation performance of the system. However, as the influent C/N was more than 3.0, Geobacter preferentially utilized organic carbon as the anodic substrate and proliferated excessively in the MFC, nitrogen conversion processes (including denitrification and bioanoammox, etc.) in the device were then inhibited resulting from the alteration in the metabolic pathway of Geobacter, ultimately leading to deterioration in nitrogen removal of the MFC. Regarding to the MFC with influent C/N of 3.0, the operational performance of the system was optimized, resulting that its COD, TN and NH₄⁺-N removal rates could respectively reached up to (93.09±0.86)%, (94.89±0.38)%, and (95.24±0.27)% during the stable operation phase, as well as the maximum power density of 85.16mW/m³. Correspondingly, Nitrosomonas, Candidatus Brocadia, Empedobacter, Geobacter, Thauera, Pseudomonas, Zoogloea, and Dechloromonas were the dominant bacterial genera in the electroactive biofilm.

Based on 110d of full-scale operational data from a municipal wastewater treatment plant in a northern Chinese city, combined with metagenomic analyses of activated sludge (N) and anoxic (A) and aerobic (O) biofilms, this study investigated pollutant removal characteristics of the AO + MBBR process under winter low-temperature conditions (13~15℃) and elucidated the associations between key functional taxa and nitrogen metabolism. The results showed that the biofilm exhibited higher microbial community richness than the suspended sludge. At the genus level, the filamentous bacterium Candidatus_Microthrix was the dominant taxon in the aerobic zone during winter, accounting for 17.63% in N and 10.12% in O, whereas Nitrospira was present at relatively low abundance (2.09% in N and 3.58% in O). According to the abundance of nitrogen-metabolism-related enzyme KOs (RPKM), Candidatus_Microthrix carried no detectable genes involved in nitrification, suggesting competitive interactions with nitrifiers. In addition, key genes for both nitrification and denitrification were most abundant in the biofilm, including AmoCAB (N=1.42, O=70.94) and NarGHI (N=410.57, A=1119.12). Redundancy analysis (RDA) further indicated that the MBBR biofilm system had higher functional gene redundancy, exhibited a more stable response to environmental fluctuations, and showed better shock resistance than the AO activated-sludge system. These findings provide a scientific basis for process optimization and operational regulation of municipal wastewater treatment plants under winter low-temperature conditions.

In order to improve the degradation efficiency of microbial electrolysis cells (MECs) treating butyric acid fermentation broth from excess sludge, this study investigated the influence of butyrate acclimation on degradation and microbial communities, with a focus on the changes of electrochemical characteristics, gas production, organics removal, and microbial community structure. Results showed that sodium butyrate acclimation enhanced current density and gas production rate during stable operation period. Moreover, when treating butyric acid fermentation broth, the acclimated system achieved higher peak current density (19A/m³), higher oxidation peak (78.1mA), and higher organics degradation rate (SCOD removal of 58.67%; VFAs removal of 41.76%), with energy recovery attaining 118.8%. Mechanism analysis revealed that sodium butyrate acclimation effectively enriched butyrate-oxidizing bacteria (Syntrophomonas), establishing more efficient metabolic pathway in comparison with sodium acetate acclimation, thereby ameliorating the degradation of butyric acid fermentation broth.