Search Results (1,010)

Severe eutrophication and frequent algal blooms in source waters (the main stream of the Yangtze River, the Jialing River tributary, and the Three Gorges Reservoir area) pose significant challenges to water treatment plants (WTPs) in Chongqing Municipality, China. This leads to reduced efficiency of conventional treatment and elevated disinfection by-products formation potential (DBPs-FP) in high algae-laden water. This study systematically evaluated the algae removal efficacy of pre-oxidation using potassium permanganate (KMnO₄) and ozone (O₃), alongside their control effects on algae-derived DBPs-FP, targeting two typical bloom-forming species: the typical cyanobacteria, i.e., M. aeruginosa and the typical diatom, i.e., Synedra sp. Results demonstrated that both low-dose O₃ and micro-acidified low-dose KMnO₄ effectively inactivated both algal species. Based on pre-treatment efficacy, targeted integrated control processes compatible with existing Chongqing WTP infrastructure were proposed. The combination of micro-acidified low-dose KMnO₄–powdered activated carbon (PAC)–conventional water treatment process was effective in controlling M. aeruginosa-derived DBPs. Conversely, the integrated sequence of low-dose O₃ pre-oxidation–conventional treatment–O₃–Biological Activated Carbon (BAC) was highly effective for controlling Synedra sp.-derived DBPs. This research provides crucial technical support and a parametric basis for optimizing treatment processes in Chongqing WTPs handling high algae-laden source waters, specifically for mitigating algae-derived disinfection by-products. Full article

Hybrid-electric powertrains have emerged as a promising solution for reducing fuel consumption and greenhouse gas (GHG) emissions in mechanized forest operations. This study presents a cradle-to-grave life cycle assessment (LCA) comparing a conventional diesel engine and a hybrid-electric powertrain used in forestry harvesters. The assessment was conducted in SimaPro using the IMPACT World+ midpoint method and the Average Dissipation Rate (ADR) approach for mineral resource dissipation. Two functional units were used: a primary, productivity-normalized unit of 1 m³ of harvested wood, and a secondary engine-level unit of one harvester engine system over a lifetime of 15,000 operating hours. Results showed that the operation phase dominated most environmental impact categories. On the engine-hour basis, the hybrid-electric powertrain reduced climate change impacts by 6.9% and fossil and nuclear energy use by 6.6% relative to the conventional diesel engine; when normalized per m³ of harvested wood using the average productivity of each system, these reductions increased to 26.4% and 26.4%, respectively, reflecting the hybrid system’s combined advantage in fuel efficiency and productivity. Most other operation-driven categories showed a similar pattern, including ozone layer depletion, terrestrial acidification, freshwater eutrophication, marine eutrophication, particulate matter formation, photochemical oxidant formation, and water scarcity. Land occupation, which increased by 10.0% for the hybrid system on an engine-hour basis, instead decreased by 13.2% on a per-m³ basis. However, freshwater ecotoxicity, human toxicity non-cancer, ionizing radiation, and mineral resource dissipation remained higher for the hybrid system on both bases, because of the additional electric motor, power electronics, and supercapacitor. Overall, the hybrid-electric powertrain improves the environmental performance of forestry harvesters on a like-for-like service-output basis, although increased material requirements and resource use for specific categories remain important trade-offs for future technology development. Full article

Despite the established clinical benefits of insoluble dietary fibers (IDF), a significant “fiber gap” persists because their inclusion often conflicts with consumer sensory expectations. While general research on dietary fibers is abundant, few studies have systematically isolated the specific impacts of individual components on food quality. To maintain scientific accuracy, we explicitly acknowledge that because the primary literature predominantly evaluates raw agro-industrial by-products (e.g., brans, pomaces, hulls) rather than isolated, chemically pure polymers, a direct, isolated causal relationship to cellulose, hemicellulose, or lignin alone is often confounded by other matrix components. Our framework thus represents a synthesis of the dominant, most plausible roles of these polymers based on converging indirect evidence, rather than causal claims tested on pure substrates. This review characterizes these components through the “Backbone–Matrix–Cement” model to understand their distinct roles in food sensory science. Following PRISMA 2020 guidelines, a systematic search was conducted across ScienceDirect, Web of Science, Google Scholar, and PubMed. The review synthesized data from 106 sources, with 80.2% (85/106) published in the last five years (2020–2026). Data extraction included fiber type, food matrix, and analytical methods, with results grouped thematically. Cellulose (the Backbone) is crystalline, providing mechanical strength and structural stability; it is naturally white and flavor-neutral, primarily influencing firmness and hardness. Hemicellulose (the Matrix) has a high capacity for hydration and acts as a gelling medium. It improves moisture retention and softness in products like bakery goods. Lignin (the Cement) is a rigid, hydrophobic aromatic polymer that is most detrimental to palatability. It consistently causes darkening, bitterness, and astringency. The “coarse granular sensation” or gritty mouthfeel emerged as the primary barrier to consumer acceptance, largely driven by lignin and large cellulose particles. To mitigate these drawbacks, the review identifies several technological interventions: mechanical micronization, biological modifications (such as sourdough fermentation and enzymatic treatments), and chemical modifications (including ozonation and carboxymethylation). For optimal acceptance, formulation levels should generally remain below 10% in bakery products, keeping average particle sizes below the 150–200 µm threshold. Successful development of high-fiber functional foods requires targeted processing strategies that address the specific sensory liabilities of each component while maintaining nutritional efficacy. Full article

Oxygen carriers (OCs) are essential materials in chemical looping technologies for low-carbon hydrogen production; however, the environmental implications of their synthesis remain insufficiently explored. This study presents a gate-to-gate life cycle assessment (LCA) of a chamotte–nickel OC produced via wet impregnation, following ISO 14040/44 guidelines. The functional unit was defined as 1 kg of oxygen carrier (OC), with input material requirements including chamotte, nickel nitrate, and water, as part of the synthesis process. Environmental impacts were modelled using ReCiPe 2016 Midpoint (H). Environmental hotspots varied across impact categories, with wet impregnation and energy-intensive thermal processes showing substantial contributions, while transportation-related burdens were relevant in selected toxicity and resource-related categories. Wet impregnation contributed 38.93% to climate change, approximately 55.6% to ozone depletion, and approximately 95.6% to terrestrial acidification in the modelled inventory. Thermal treatments also contributed substantially to several impact categories, primarily because of their high electricity requirements. Hotspot analysis identified precursor selection, energy supply, and logistics as key drivers of environmental burdens. Qualitative mitigation options include precursor substitution, renewable-energy integration, energy-efficiency improvements, and industrial symbiosis; however, these alternatives were not quantitatively evaluated in the present LCA. These results offer actionable guidance for sustainable OC design and highlight the importance of integrating LCA into early-stage oxygen-carrier design to reduce the environmental burdens associated with material synthesis. Further assessment incorporating OC performance, lifetime, regeneration, and hydrogen yield would be required to determine the implications of these material-level improvements for the environmental performance of hydrogen production. Full article

Peak summer surface ozone (O₃) threatens human health, crop productivity, and ecosystem stability in eastern China, but similar O₃ trends may reflect contrasting anthropogenic drivers. Using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) and the Multi-Resolution Emission Inventory for China (MEIC), we examined July maximum daily 8 h average (MDA8) O₃ over the Bohai Plain and the Yangtze River Delta (YRD) from 2014 to 2020. Emission substitutions under fixed 2014 meteorology isolated the O₃ responses to changes in total emissions and individual pollutants. Although O₃ levels were high in both regions by 2019 and declined sharply in 2020, the two regions showed opposite responses to emission changes. Over the Bohai Plain, substituted inventories reduced MDA8 O₃ in all later scenarios, with a 4.57 ppb decrease for the 2020 inventory. Over the YRD, emission changes increased O₃ by up to 4.70 ppb. VOC substitution produced the largest decrease over the Bohai Plain at 5.46 ppb, whereas substituting 2020 NO_x emissions increased YRD O₃ by 4.22 ppb. The joint NO_x and VOC substitution increased YRD O₃ by 4.97 ppb, revealing a nonadditive response. Formation sensitivity also diverged, with the western Bohai Plain shifting toward VOC-sensitive conditions and NO_x sensitivity strengthening in the northern YRD. These results show that similar peak summer O₃ evolution can conceal fundamentally different emission responses. These findings support region-specific multipollutant control strategies for the two regions. Full article

Emission reduction remains the foundation of air-pollution control, yet the relationship between reduced emissions and improved ambient air quality is frequently non-proportional. This mismatch is not an exception to atmospheric behavior but a consequence of coupled chemical, meteorological, transport, and removal processes. Here, we critically synthesize global evidence for nonlinear air-quality responses to emission controls, with particular attention to fine particulate matter (PM_2.5) and ozone (O₃). We distinguish five response forms that are directly relevant to policy: near-linear, sublinear, superlinear, threshold, and sign-reversal behavior. Ozone provides the clearest example because the response to nitrogen oxides (NOx) and volatile organic compounds (VOCs) depends on the prevailing photochemical regime and can change as emissions decline. PM_2.5 responses are likewise nonlinear because precursor controls alter atmospheric oxidation capacity, gas-particle partitioning, aerosol water, and interactions among nitrate, sulfate, ammonium, and secondary organic aerosol. Aerosol reductions can further modify photolysis and boundary-layer processes, linking PM_2.5 control to O₃ production. Regional transport and background concentrations attenuate or redistribute the benefits of local controls, while meteorological variability changes both chemical sensitivity and the realized concentration response. These mechanisms imply that sustainable air-quality management cannot be evaluated solely by tonnes of emissions avoided. Instead, policy performance should be assessed along the complete pathway from emission reduction to ambient concentration, exposure, health, climate, ecosystem, equity, and economic outcomes. We propose a sustainability-oriented framework in which control strategies are evaluated for atmospheric effectiveness, multipollutant coherence, spatial equity, climate compatibility, and robustness across changing chemical and meteorological regimes. The evidence supports adaptive, coordinated, and regionally integrated control portfolios rather than fixed single-pollutant reduction ratios. Full article

To characterize summertime ozone (O₃) pollution at the Dianshan Lake suburban site, hourly surface observations and 15 min ozone-lidar profiles were collected during June–August 2022. Monthly mean O₃ increased progressively from June through August (89.0 ± 47.4 to 102.1 ± 59.3 μg/m³), while VOCs averaged 33.9 ± 22.4 μg/m³, dominated by alkanes (53.1%), followed by aromatics (30.3%), alkenes (14.4%) and alkynes (2.3%). A representative high-O₃ episode revealed NO + HO₂ as the dominant production pathway (60.0%), whereas O₃ loss was dominated by the NO₂ + OH pathway forming HNO₃ (75.9%). Sensitivity analysis supported a VOC-limited response during the modeled 9–14 August episode; the transition in the tested joint-reduction scenarios occurred near a VOCs/NO_x ratio of 0.80 but was model-sensitive. Integrating concentrations, ozone formation potential (OFP), and OH Loss Rates (L_OH) prioritized isoprene, propylene, ethylene, m/p-xylene, toluene, and i-pentane for control. The reproduced five-factor PMF solution attributed 25.7% to gasoline vehicle exhaust, 24.6% to LPG/NG use, 21.2% to biogenic emissions, 15.1% to solvent use, and 13.4% to diesel vehicle exhaust. Full article

Emission inventories at fine spatial and temporal scales were developed for light alkanes, volatile organic compounds (VOCs), and nitrogen oxides (NO_x) from upstream and midstream oil and gas operations in the Permian Basin oil and gas production region for 2022–2024. The inventories were spatially aggregated at basin, county, and 12 km by 12 km grid cell levels, and temporally resolved at hourly resolution, with underlying methods capable of generating inventories at other spatial and temporal scales. Spatial and temporal variability in emissions in the Permian were compared at various spatial scales with inventories for the Marcellus oil and gas production region, developed using the same methods. Emission sources that drive spatial and temporal variability differ by regional production characteristics, the level of spatial aggregation, and emitted species. Temporal variability in emissions decreases as the scale of spatial aggregation increases. Among counties with at least 10 active producing wells, maximum-to-annual-average hourly emission rate ratios reached 2.5 for methane, 2.8 for VOCs, and 2.3 for NO_x. At the 12 km by 12 km grid cell level, the corresponding maximum ratios were 33.7, 26.5, and 13.9. These ratios illustrate the magnitude of short-term emission variability and the extent to which peak hourly emissions can exceed annual average estimates, with potential implications for episodic air-quality impact assessment. Compared with the gas-dominated Marcellus Basin, the oil-dominated Permian Basin shows lower temporal variability in hydrocarbon emissions due to fewer episodic gas production related sources (e.g., liquid unloadings) and a greater contribution from near-continuous oil production related sources (e.g., associated gas venting and tank flash). In contrast, NO_x emissions exhibit higher temporal variability in the Permian due to more frequent preproduction activities associated with new well development. The spatially and temporally resolved emission inventories by source category and chemical species can be further combined with chemical transport modeling and air quality modeling to support assessment of regional air quality events, such as localized and episodic ozone formation. Full article

Legionella pneumophila, the causative agent of Legionnaires’ disease, remains a major public health concern in water systems. Chlorination is the most widely used disinfection strategy but presents important limitations, including reduced stability in hot water systems and the generation of carcinogenic by-products. This study evaluated ozonation as an alternative disinfection method, comparing its efficacy with chlorination against different physiological states of L. pneumophila, including culturable and viable but non-culturable (VBNC) cells, as well as biofilm-associated bacteria and amoebal hosts. The biocidal effect of ozone and chlorination on planktonic L. pneumophila was assessed by culture and viability-qPCR. Biofilm viability was evaluated using fluorescein diacetate staining, whereas amoeba viability was determined by flow cytometry. Ozonation achieved complete inactivation of both culturable and VBNC L. pneumophila within 5 min. In contrast, chlorination achieved complete loss of culturability only at high concentrations and was associated with the persistence of VBNC cells. Neither ozonation nor chlorination significantly reduced established biofilms or amoebae. These findings indicate that ozonation is a promising strategy for rapid inactivation of planktonic L. pneumophila and may overcome important limitations associated with chlorine-based treatments. Full article

This study proposes a self-condensing water-electrode plasma device in which ambient water vapor is condensed on a cooled needle-tip electrode within a strong electric-field region, forming continuously renewed water droplets, Taylor cones, or water-film interfaces that participate in the discharge process. The effects of ambient humidity, needle-tip temperature, and applied voltage on the self-condensation behavior were investigated. The discharge modes at different applied voltages and discharge gaps, the generation of reactive species, and the inactivation efficacy against Staphylococcus aureus were also analyzed. The results showed that increasing ambient humidity, decreasing the needle-tip temperature, and increasing the applied voltage all promoted water condensation at the needle tip. The electric field shortened the droplet formation time and reduced the droplet detachment size. As the applied voltage increased, the device sequentially underwent water condensation, electrospray, stable Taylor-cone, water-film discharge, and bare-electrode discharge stages, while the boundary voltage of each stage increased with the discharge gap. The ozone concentration remained below the instrument’s limit of detection during discharge with the self-condensing water electrode, whereas hydroxyl-radical generation was significantly enhanced. Compared with a conventional metal electrode, the self-condensing water electrode exhibited greater inactivation of S. aureus at the same applied voltage, with a more pronounced advantage under low-voltage conditions. These findings demonstrate that introducing a self-condensing water interface can regulate the local discharge morphology and reactive-species composition, providing a new strategy for developing low-temperature plasma sterilization technologies with low ozone production and high bactericidal activity. Full article

Contaminated soil remediation is of increasing importance due to the environmental and health risks associated with hazardous pollutants. Solidification/stabilization (S/S) is a widely adopted remediation technique; however, its environmental performance is often limited by the high demand for Portland cement. This study evaluates the environmental impacts of a conventional cement-based S/S system and an alternative formulation incorporating ground granulated blast furnace slag (GGBFS), washed fly ash (W-FA), and marble sludge (MS) using a comparative Life Cycle Assessment (LCA). The assessment was performed using SimaPro 9.3, the Ecoinvent v3.9 database, and the ReCiPe 2016 Midpoint (H) method, within a cradle-to-gate system boundary. Particular attention was given to developing a transparent and reproducible life cycle inventory, integrating primary operational data with background datasets for all material and energy flows associated with the remediation process. The results show that replacing a substantial portion of Portland cement with industrial by-products reduces Global Warming Potential by approximately 27%, while smaller reductions of approximately 20% are observed for ozone formation, human health and ozone formation, and terrestrial ecosystems, respectively. Conversely, the Green S/S formulation shows higher impacts across most of the remaining midpoint categories, including ionizing radiation; terrestrial, freshwater, and marine ecotoxicity; human toxicity; eutrophication; resource scarcity and water consumption. These increases reflect upstream elementary flows and processing requirements associated with the alternative binder constituents included within the adopted cradle-to-gate system boundary. Overall, the results demonstrate that the environmental performance of the alternative formulation is characterized by clear category-specific trade-offs rather than a uniform reduction across impact categories. The findings highlight the potential of industrial by-products to reduce cement-related climate impacts while emphasizing the need for a multi-impact life-cycle perspective when evaluating alternative S/S formulations for contaminated soil remediation. Full article

Surface ozone (O₃) adversely affects winter wheat production. However, due to the lack of spatially continuous ozone exposure datasets directly linked to crop yield responses, the assessment of ozone-induced crop losses remains uncertain. Winter wheat, a major food crop in China, is highly sensitive to ozone. Its primary cultivation region—the North China Plain (NCP)—overlaps with severe ozone pollution areas, creating significant risk asuperposition. To address this, we employed a spatiotemporal LightGBM (ST-LightGBM) model with ground observations, atmospheric reanalysis, and satellite retrievals to reconstruct a 10 km resolution dataset of daily 7 h average (M7) and daytime accumulated ozone exposure index (AOT40) across China from 2015 to 2022. The model performed robustly; SHAP analysis showed that downward solar radiation and 2 m temperature explained over 42% of ozone variability. From 2015 to 2022, despite pollution controls and the COVID-19 pandemic, surface ozone showed a phased upward trend (0.83 μg m⁻³ yr⁻¹), with O₃ concentrations increasing across 79.22% of the study area and the NCP most affected. Applying M7 and AOT40, the average annual relative yield loss of winter wheat ranged from 3.44% to 7.20% (M7) and from 26.50% to 36.54% (AOT40), corresponding to economic losses of 2.21–4.44 billion USD and 16.16–26.08 billion USD. Both metrics showed consistent trends, but AOT40 losses were substantially higher, highlighting the need to incorporate cumulative high-concentration exposure into agricultural risk assessments. These findings demonstrate that O₃ pollution poses a substantial threat to winter wheat production in China. The reconstructed exposure metrics provide a quantitative basis for identifying high-risk agricultural regions and inform targeted mitigation strategies to safeguard food security under intensifying O₃ pollution. Full article

Municipal sludge generation has increased rapidly with urbanization, creating significant challenges for sustainable waste management. This review proposes a system-oriented framework for sludge resource utilization by linking sludge characteristics, conversion technologies, environmental risks, and product applications. Major treatment pathways, including anaerobic digestion, pyrolysis, ozonation, and hydrothermal carbonization, are critically compared, with emphasis on their inherent trade-offs between resource recovery, energy consumption, and contaminant control. Particular attention is given to emerging contaminants, such as microplastics, per- and polyfluoroalkyl substances (PFAS), and antibiotic resistance genes, where the distinction between pollutant removal and actual risk reduction remains insufficiently addressed. The review highlights that no single technology can achieve optimal performance under all conditions, and integrated treatment trains are generally required for sustainable sludge management. Among these pathways, pyrolysis shows considerable potential for applications requiring enhanced contaminant control and value-added biochar production due to its ability to promote organic contaminant degradation, heavy metal immobilization, and carbon storage. However, the feasibility of pyrolysis and other technologies depends strongly on site-specific factors, including sludge properties, energy availability, economic conditions, and regulatory requirements. Future research should focus on integrated process optimization, comprehensive pollutant fate assessment, and standardized evaluation frameworks to advance sludge management toward a circular economy. Full article

Coastal green tides may alter nearshore bioaerosols through coupled marine, atmospheric, and meteorological processes, yet their effects on airborne microbial communities remain poorly resolved. Atmospheric samples were collected in Aoshan Bay, Qingdao, China, during five phases of the Ulva prolifera green tide in 2019 (pre-bloom, 19 April; early bloom, 15 June; middle bloom, 15 July; late bloom, 6 August; post-bloom, 30 August); seawater samples were collected at one nearshore site on each of the five sampling dates, with microbial sequencing performed for the middle-bloom (15 July) and late-bloom (6 August) phases. Bacterial and fungal communities were characterized; although bioaerosols may also contain microalgae and viruses, this study profiled only the bacterial and fungal fractions, using bacterial 16S rRNA gene (V3-V4 region) and fungal internal transcribed spacer (ITS2) amplicon sequencing and evaluated together with meteorological variables, air-pollutant concentrations, and 72-h backward air-mass trajectories. Proteobacteria dominated the airborne bacterial assemblages (81.28–97.83%), with Sphingomonas as the most abundant genus (47.85–89.84%). Basidiomycota and Ascomycota dominated the fungal assemblages, whereas Cryptococcus and Alternaria were the major fungal genera. Community richness and composition varied across bloom phases. Chytridiomycota was undetected before the bloom (0%), appeared after bloom onset, and reached its highest relative abundance during the middle phase (8.19%). Spatial patterns indicated joint terrestrial and marine influences, although bacterial communities in seawater and air remained highly dissimilar. Temperature, relative humidity, particulate matter, ozone, and air-mass origin were associated with changes in microbial diversity and composition. These findings provide an observational baseline for coastal bioaerosol dynamics during a macroalgal green tide, extending the HAB–bioaerosol literature—which has focused predominantly on cyanobacterial blooms—to a large green macroalga. Bacteria and fungi showed contrasting environmental responses: bacterial richness increased with temperature, whereas fungal diversity declined. Greater compositional similarity between seawater and air for fungi than for bacteria suggests differential environmental filtering at the air–sea interface and implies that multiple source pathways—direct aerosolization, sea-surface release, and in-situ atmospheric production—may differentially shape the two domains. Given the single-date-per-phase sampling design, the absence of sequenced laboratory contamination controls, and the lack of absolute abundance data, these results should be regarded as preliminary and hypothesis-generating, underscoring the need for ASV-level source tracking, controlled chamber experiments, and replicated multi-year designs in future assessments of bloom–atmosphere interactions. Full article

Quantifying the large-scale impact of combined ozone (O₃) and nitrogen dioxide (NO₂) pollution on terrestrial carbon sinks remains a major challenge. Here, we develop a parsimonious yet robust empirical framework that leverages high-resolution remote sensing datasets (CHAP O₃/NO₂ and MODIS NPP, 2008–2021) to characterize nonlinear threshold responses of terrestrial net primary productivity (NPP) across China’s diverse ecosystems. Our observational analysis identifies only associative temporal relationships between annual NPP variability and pollutant concentrations, with NPP positively correlated with O₃ (Pearson’s r = 0.714, p < 0.01) and negatively correlated with NO₂ (r = −0.599, p < 0.05). Notably, the ecosystem-specific threshold values (O₃: 28,324–34,391 μg m⁻³ yr⁻¹; NO₂: 3646–4968 μg m⁻³ yr⁻¹) are statistically derived from spatially aggregated pixel-level records across the full 14-year period, independent of the national annual time-series correlation analyses. Distinct from previous single-pollutant national evaluations, our study advances a novel analytical framework focusing on the interactive and combined impacts of O₃ and NO₂ co-exposure. The results demonstrate that NPP displays an increasing trend under low-level pollutant exposure but declines substantially once pollutant loads exceed the identified threshold ranges. Based on K-means clustering and segmented regression analyses, we estimate a national average NPP reduction of 17.4% per year (−0.68 Pg C yr⁻¹), resulting in a cumulative carbon loss of −9.48 Pg C over the 14-year study period—equivalent to 2.45 years of China’s total terrestrial carbon uptake. Among all ecosystem types, forestlands experience the largest cumulative carbon loss (−4.22 Pg C), with prominent loss hotspots concentrated on the Tibetan Plateau and Northwest China. This refined national-scale assessment of dual-pollutant impacts provides observation-based evidence of substantial terrestrial carbon sink degradation, underscoring the necessity of combined air pollution mitigation strategies to sustain ecosystem stability and climate mitigation targets. Full article