Search Results (348)

The global methane budget is largely driven by biogenic sources, many of which remain insufficiently characterized. Here, we investigated the community composition and seasonal dynamics of methanogenic and methanotrophic assemblages to elucidate the key contributors to methane cycling and the environmental factors shaping these processes in lake sediments of the Rila Mountains (Bulgaria). Methanogenic communities are primarily composed of Methanothrix, Methanosarcina, Methanobacterium and Methanoregula with summer peaks in Methanothrix and Methanoregula, and cold-season proliferation of Methanobacterium. Methanotrophic communities are dominated by representatives of the Pseudomonadota, including Crenothrix, Methylobacter, and Methylocystis with summer maxima observed for Crenothrix and Methylobacter. Methanosarcina and Methylocystis showed relatively stable abundances throughout the ice-free season. Ordination and correlation analyses revealed that temperature, pH, and carbon (organic and inorganic) concentration and lability emerged as the environmental drivers influencing on microbial communities, with seasonally variable effects on methane-cycling microorganisms. These findings provide a foundation for future research on methane cycling in alpine lake ecosystems of the Rila Mountains and contribute to improving predictions of methane emissions under changing climatic conditions. Full article

This study explores the potential of utilizing biogenic manganese oxides (BMOs) produced by Mn-oxidizing Pseudomonas putida MnB1 to facilitate metal cation uptake for rare earth element (REE) sequestration and the synthesis of novel materials. Previous studies have shown that P. putida MnB1 efficiently oxidizes environmental Mn(II) to Mn(IV)-oxides, producing BMOs with unique physicochemical properties. Unlike their abiotic counterparts, BMOs exhibit high surface area, reactivity, and amorphous, poorly crystalline structures, making them promising platforms for adsorbing metal cations. This research study, building on the prior work, demonstrates the incorporation of ten different main group, transition, and rare earth metals into the BMO material, with structural characterization conducted via scanning electron microscopy and powder X-ray diffraction. Compositional characterization was determined by inductively coupled plasma optical emission spectroscopy and energy dispersive X-ray spectroscopy via scanning electron microscopy. Following the initial screening of these ten cations, batch adsorption studies were performed for a representative light REE, heavy REE, and transition metal-spiked sample prepared with real wastewater effluent indicating that the BMO material in this study is promising for sequestering REEs from real water streams. These findings advance the understanding of biologically mediated metal adsorption and open pathways for designing new functional materials with potential applications in rare earth sequestration and catalysis. To highlight this later point, the BMO materials with an incorporated main group (Al³⁺, Ca²⁺) or transition metal cation (Fe³⁺, Cu²⁺) were tested electrochemically for their ability to act as water oxidation catalysts, and each of these materials’ activity was comparable to BMO except for the material with incorporated iron, which showed significantly enhanced activity. Full article

Hydrothermal activity plays a critical role in ancient oceanic environments, organic matter accumulation, and metallic ore deposit formation. During the Early Cambrian, the development of hydrothermal systems in the southern Anhui Province of the Lower Yangtze Block has long attracted geological attention. This study focuses on the Lower Cambrian black shales of the Hongtaocun (HTC) section in the southern Anhui Province, employing major- and trace-element analyses, rare earth element (REE) geochemistry, and field-emission scanning electron microscopy (FE-SEM) observations to identify evidence for Early Cambrian hydrothermal activity on the Yangtze Platform and its controls on mineralization. Our results demonstrate that major-element proxies classify the HTC samples as biogenic, but this classification is demonstrably incorrect given the mineralogical and REE evidence, which highlights the limitations of major-element discrimination alone. Hyalophane (Hy) occurrence records Ba-rich hydrothermal fluids, while positive Eu anomalies in the REE patterns further corroborate hydrothermal influence. We, therefore, emphasize that major-element chemistry alone is insufficient to reliably identify hydrothermal processes. These findings substantially advance the discrimination criteria for ancient seafloor hydrothermal activity. Full article

This study examines a cold-press manufacturing method for laminated bamboo and bamboo–timber composites, together with a cradle-to-gate carbon footprint analysis of the produced materials. The proposed material systems are assessed as alternatives to conventional engineered bamboo and to widely used construction materials such as structural steel, concrete, and aluminum. Existing engineered bamboo products are typically manufactured using hot pressing and formaldehyde-based adhesives, both of which contribute to their environmental burden. The present work therefore considers a more practical and environmentally responsible route based on lower-energy processing and lower-emission adhesive systems. Following a cradle-to-gate carbon footprint analysis of the produced materials, the embodied carbon values obtained for the four systems are 473.3, 322.3, 314.2, and 210.3 kg CO₂e/m³ for the BBE, BPA, CBE, and CPA specimens, respectively. Relative to conventional hot-pressed laminated bamboo, these values correspond to embodied carbon reductions of 26.8%, 50.1%, 51.4%, and 67.5%, respectively. When the biogenic carbon stored in the bamboo and pine biomass is included, the net carbon balances become −415.5, −607.1, −597.0, and −618.6 kg CO₂e/m³, respectively. These results show that the proposed engineered bamboo and bamboo–timber composites offer feasible low-carbon options for construction applications. Full article

Coordinated control of fine particulate matter (PM_2.5) and ozone (O₃) is an urgent national strategic priority for China’s air pollution governance. Biogenic volatile organic compounds (BVOCs) are important precursors of O₃ and secondary organic aerosol (SOA). To quantify the species-specific impacts of BVOCs, we used the Model of Emissions of Gases and Aerosols from Nature (MEGAN, v3.2) and the Community Multiscale Air Quality (CMAQ, v5.3.2) model to investigate BVOC emission characteristics and their modulating effects on summertime O₃ and PM_2.5 across China. In July 2020, total BVOC emissions were 6.50 × 10⁶ tons, showing a spatial pattern that decreased from southeast to northwest and a unimodal diurnal variation that peaked at 13:00–14:00. BVOC emissions significantly promoted O₃ formation, with a maximum concentration increment of 47.36 μg m⁻³ in VOC-limited regions such as the Sichuan Basin (SCB) and Yangtze River Delta (YRD). Their impact on PM_2.5 was limited, with most regional increments below 3 μg m⁻³. Isoprene dominated O₃ enhancement, while monoterpenes acted as the key BVOC for PM_2.5 via SOA formation. Anthropogenic emission reductions elevated the relative contribution of BVOC emissions to air pollution in most regions. These findings highlighted the importance of considering BVOC emissions and their species-specific effects in China’s coordinated PM_2.5-O₃ control strategies for more precise air quality management. Full article

The construction sector is responsible for significant global energy consumption and CO₂ emissions, largely driven by carbon-intensive materials such as ordinary Portland cement and steel. In response to increasing decarbonization and circular economy demands, several strategically relevant categories of sustainable construction materials have been developed, particularly natural and bio-based systems, recycled and waste-derived materials, low-carbon cementitious binders, and emerging multifunctional composites. However, research remains fragmented across material classes and performance metrics. This systematic review evaluates advances published between 2018 and 2026 following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 methodology. Peer-reviewed studies were systematically identified and analyzed to compare mechanical performance, durability, embodied carbon reduction, and life-cycle environmental impacts across these selected material pathways. The results indicate substantial decarbonization potential. Low-carbon cementitious materials report CO₂ reductions of approximately 10–75% relative to conventional systems, while engineered timber and bamboo demonstrate 28–70% lower carbon footprints due to reduced embodied energy and biogenic carbon storage. Recycled aggregates and industrial by-products enhance circularity but remain sensitive to transport distance and processing intensity. Trade-offs between mechanical capacity and environmental performance are evident in lightweight and bio-based systems. Overall, sustainability gains are maximized through integrated hybrid construction strategies rather than isolated material substitution. This review provides a comparative evidence-based synthesis and identifies key research gaps and implementation challenges for accelerating low-carbon construction. Full article

The escalating global challenge of waste management, combined with the urgent need to reduce greenhouse gas emissions, has intensified interest in waste-to-energy (WtE) technologies as integrated solutions for sustainable energy recovery. This review critically examines advanced WtE technologies through three interconnected dimensions: the strength of the evidence base supporting performance and environmental claims, the challenges associated with scalability and system integration, and the implications of these technologies for net-zero energy transitions. The analysis covers thermochemical, biochemical, and hybrid conversion pathways, including pyrolysis, gasification, hydrothermal liquefaction, and anaerobic digestion, with particular emphasis on identifying inconsistencies in the literature and clarifying key uncertainties. A persistent gap between laboratory-scale performance and commercial-scale operation is identified and characterised across conversion pathways. Its principal drivers of feedstock heterogeneity, heat transfer limitations, and operational complexity are examined. Environmental assessments are shown to be highly sensitive to system boundary definitions and carbon accounting methodologies, with lifecycle results varying substantially depending on energy substitution assumptions and biogenic carbon treatment. The integration of WtE within circular economy frameworks demonstrates that energy recovery is most effective when positioned as a complement to material recycling rather than a substitute. The roles of combined heat and power configurations, district heating, carbon capture and storage, and emerging reactor technologies in advancing net-zero contributions are assessed. Significant data gaps are identified in long-term operational performance, modelling transparency, and reporting standardisation. The review concludes that WtE technologies represent valuable components of integrated waste and energy management systems, but their long-term contribution to decarbonisation requires careful system design, sound operational strategies, and harmonised performance evaluation frameworks. Full article

Improving the energy performance of existing multi-apartment residential buildings is critical for reducing energy consumption and greenhouse gas emissions in Central and Eastern Europe, where large stocks of post-war buildings with limited insulation are connected to district heating systems. This study evaluates façade insulation retrofit strategies for two representative typologies in Novi Beograd, Serbia—a high-rise tower and an elongated slab-type (‘lamella’) building—using calibrated dynamic energy models and cradle-to-use lifecycle assessment (LCA) over a 50-year service life. Models were calibrated against measured 2023–2024 heating consumption data (NMBE < 1%, CVRMSE < 15%) and normalized with Typical Meteorological Year weather for consistent scenario comparison. Retrofit scenarios applied expanded polystyrene (EPS) and cellulose insulation at 10, 12, and 15 cm thicknesses. Results show that external insulation reduces annual heating demand by approximately 19–20% compared to the uninsulated baseline (192 kWh/m²·a), with the majority of savings achieved at 10 cm and only marginal gains from additional thickness. Insulation thickness has a stronger influence on operational energy reduction than material choice, as differences between EPS and cellulose remain below 0.5%. LCA indicates 23.6–26.0% lower climate change impacts and 23.6–25.8% reduced cumulative energy demand in retrofit scenarios, with cellulose offering modest advantages due to lower embodied emissions and biogenic carbon storage. These findings support targeted envelope retrofits as an effective strategy for decarbonizing district-heated residential buildings in the region. Full article

Novel carbon-storing construction materials have the potential to reduce greenhouse gas emissions by removing carbon dioxide from the atmosphere and storing it in long-lived building products. In order to understand the full benefits and shortcomings of carbon-storing materials, life cycle assessments (LCAs) must be performed. However, material innovators who are looking to perform LCAs of their products during early-stage research and development (R&D) face many challenges. While these challenges have been reported in the literature, this information has been fragmented and required a more comprehensive investigation. We explored these LCA challenges by holding an in-person workshop with sixteen R&D teams who were developing carbon-storing materials and building designs. From the data collected in this workshop, we found that the R&D teams struggled with data availability, biogenic carbon, and uncertainty, which confirmed our findings from the literature. They also struggled with various other LCA topics. Since current LCA tools lack functions that would be useful for this user group, we also proposed a list of tool ideas that could address their LCA needs, which can inform future LCA tool development. Full article

This qualitative systematic review evaluates the potential of modular prefabricated OSB/plywood housing systems in low-technification, high-seismicity settings. These systems are promoted as low-carbon options for emerging contexts, and we assess how far the evidence supports that promise and under which conditions they can contribute to net-zero housing pathways. An adapted PRISMA 2020 workflow was applied to Scopus (TITLE-ABS, 2000–2025); 153 studies were synthesized in a table-first, coded matrix into axes for structural, digital fabrication, sustainability/circularity, and extrapolatable systems—supplemented by curated housing cases—with other EWPs used only for contrast. To address fragmentation and heterogeneity across domains, we developed a domain-based QA/QC instrument (STRUCTURAL, LCA, and FABRICATION) to judge whether studies provide minimally comparable evidence. Structural performance is relatively mature for certain patterns (calibrated FEM, cyclic tests, some 1:1 trials), whereas digital fabrication and LCA evidence remain partial: file-to-factory workflows rarely report verifiable QA/QC traceability, and most LCAs stop at A1–A3 with uneven treatment of A4, C/D, and biogenic carbon. Full convergence of adequate STRUCTURAL, LCA, and FABRICATION evidence within the same system type is rare, so both transferability to low-technification, seismic-prone settings and alignment with net-zero objectives must be characterized as conditional rather than established. The review identifies minimum multi-domain thresholds—technical robustness, whole-life LCA coverage, and verifiable QA/QC—as prerequisites for positioning modular OSB/plywood housing as a credible low-carbon pathway. These conclusions are limited by Scopus-only, English-language coverage and methodological heterogeneity, especially in the LCA. Full article

Beef production is widely recognized as a significant contributor to global greenhouse gas emissions, making robust and transparent environmental assessments essential for advancing sustainability within supply chains. This study applies a comprehensive cradle-to-grave Life Cycle Assessment (LCA) to evaluate the environmental performance of beef destined for export, following ISO 14040, ISO 14044 and ISO 14067 standards and the Product Category Rules for meat of mammals. Sixteen impact categories were quantified for 1 kg of vacuum-packed beef using detailed primary data from a pasture-based production system and a representative processing facility. The total climate change impact was 3.27 × 10¹ kg CO₂eq, with enteric methane and feed production jointly responsible for over 70% of overall impacts. Slaughtering and distribution were associated mainly with fossil energy use and ozone depletion, while soil carbon sequestration partially compensated biogenic emissions. The results were consistent with international benchmarks, highlighting the environmental advantages of pasture-based systems, low fertilizer use, and stable land management. Key hotspots were identified in animal growth, feed efficiency, and manure management, with logistics also contributing notably. Overall, the study provides a high-resolution environmental baseline that can support Environmental Product Declarations and guide targeted mitigation strategies across beef supply chains. While the results are derived from a specific pasture-based production system, the study is positioned as a case-study-based application of a high-resolution LCA framework, illustrating how detailed inventories can support environmental benchmarking and hotspot identification without implying statistical representativeness of all beef production systems. Full article

Brazil is the main coffee producer in the world. However, the impacts of climate change driven by greenhouse gas (GHG) emissions pose a major challenge for agriculture in tropical regions. This study established a GHG inventory of coffee production on farms in southern Minas Gerais, Brazil, over a two-year period, adopting a cradle-to-farm-gate approach. It considered scopes 1 and 2 emissions from on-farm activities. The emission inventories were based on Intergovernmental Panel on Climate Change (IPCC) methodologies adapted for Brazilian conditions. The emissions were categorized in direct and biogenic and by area (in hectares) and production (kg of coffee). Electricity consumption, fossil fuel use, wood burning and fertilizer application were considered. Direct total emissions ranged from 2617 to 6211 t CO₂e, 2.67 to 3.81 t CO₂e ha⁻¹, and from 1.52 to 4.59 kg CO₂e kg⁻¹ of coffee. Biogenic emissions ranged from 336 to 4955 t CO₂e, 0.28 to 2.95 t CO₂e ha⁻¹, and from 0.32 to 2.21 kg CO₂e kg⁻¹ of coffee. Urea-based nitrogen fertilizers were the main source of direct emission and wood burning was the main source of biogenic emission. Management practices such as applying non-urea-based fertilizers, adjusting nitrogen rates according to soil analyses and manual harvesting contributed to mitigating GHG emissions. The observed emission intensities were consistent with other reported values for Brazilian coffee production. Further reductions may be achieved by adopting agroforestry systems, increasing coffee straw retention in the soil and replacing urea with alternative nitrogen sources, including slow-release fertilizers and urease-inhibitor technologies. Full article

Volatile organic compounds (VOCs) are key precursors of ozone (O₃) and secondary organic aerosols (SOA), among which biogenic VOCs (BVOCs) constitute the dominant natural source. However, large uncertainties remain in the magnitude, spatial distribution, and seasonal variability of BVOC emissions in China under rapidly changing vegetation and climate conditions. In this study, a refined BVOC emission inventory for China in 2023 was developed using the Model of Emissions of Gases and Aerosols from Nature (MEGAN v3.2) driven by WRF meteorological simulations and MODIS vegetation data. The estimated annual BVOC emissions reached 41.70 Tg, including 26.90 Tg isoprene, 4.84 Tg monoterpenes, 0.55 Tg sesquiterpenes, and 9.41 Tg other VOCs. The corresponding ozone formation potential (OFP) and secondary organic aerosol formation potential (SOAFP) were 346.12 Tg yr⁻¹ and 2137.51 Gg yr⁻¹, respectively. Emissions exhibited a pronounced south–north gradient with hotspots in Guangxi, Guangdong, and Yunnan, and peaked in summer. Broadleaf forests were identified as the dominant emission sources, followed by savannas and shrublands. Isoprene contributed most to OFP, whereas monoterpenes dominated SOAFP. Compared with previous inventories, the updated vegetation data, meteorological inputs, and refined chemical speciation improve the representation of BVOC emissions and their spatial patterns in China. These results highlight the important role of BVOCs in regional O₃ and SOA formation and provide an improved emission basis for atmospheric chemistry modeling and air-quality management. Full article

Livestock production significantly contributes to greenhouse gas (GHG) emissions, particularly methane (CH₄) and nitrous oxide (N₂O) originating from enteric fermentation and manure management. This study quantified the GHG emissions and cumulative carbon footprint of four commercial sheep farms (SF1, SF2, SF3, and SF4) in the Bursa region of Türkiye, with flock sizes of 200, 500, 150, and 800 adult Merino sheep (mature ewes and breeding rams), respectively. Using the IPCC Tier 2 methodology, the biogenic carbon footprint was estimated at 15.6 kg CO₂-eq per kg of boneless sheep meat. However, when indirect inputs were included, the cumulative carbon footprint reached 28.8 kg CO₂-eq for ewes and 32.3 kg CO₂-eq for breeding rams. These results indicate that indirect emissions from feed production account for the primary environmental load (49.8%), while on-farm energy-related emissions represent a minor portion (0.3%) of the total impact. The results demonstrate that while enteric fermentation (32.5%) remains a critical biological factor, the environmental burden of the feed supply chain is equally significant in intensive systems. These findings highlight that excluding indirect inputs leads to a substantial underestimation of the climate impact, suggesting that mitigation strategies must integrate nutritional optimization with enteric methane reduction to decarbonize sheep production effectively. Full article

Naphthalene and methylnaphthalene (Nap and MN) are the most abundant polycyclic aromatic hydrocarbons (PAHs) and are important precursors of secondary organic aerosol (SOA) in the atmosphere. 1.2-Phthalic acid (1,2-PhA) and 4-methylphthalic acid (4-MPhA) are usually treated as tracers of SOA from Nap and MN. However, the two tracers also have primary sources, and directly using the tracers to estimate SOA would lead to an overestimation. In this study, we conducted a one-year synchronous observation of the two-ring PAH SOA (SOA_2-rings) tracers at nine sites in the Pearl River Delta (PRD) region. We measured and filtered the suitable emission characteristics of SOA_2-rings tracers for biomass burning, coal combustion, industrial processes and vehicle exhaust sources. Then, we developed a method to distinguish 1,2-PhA and 4-MPhA from primary emissions and secondary formation. The average proportions of 1,2-PhA_pri and 4-MPhA_pri in 1,2-PhA and 4-MPhA were 26.7% and 29.2%, respectively. The direct application of measured 1,2-PhA for estimating SOA_2-rings would lead to an overestimation exceeding 30% in the PRD. Furthermore, we estimated SOA_2-rings using the separated 1,2-PhA_sec and 4-MPhA_sec by the tracer-based method. The average contribution of MN to SOA was around three times that of Nap. In addition, when combined with monocyclic aromatic SOA (SOA_1-ring) and biogenic SOA, the contributions of SOA_1-ring (21%) and SOA_2-rings (25%) to total SOA were comparable. SOA_2-rings was even the largest contributor to total SOA (~44%) in winter. This study revealed that whether to separate the SOA_2-rings tracers for primary emissions and secondary formation is essential in SOA estimation and highlighted that two-ring PAHs make a significant contribution to SOA in the PRD. Full article