Search Results (9,148)

The global plastic pollution crisis demands a fundamental re-evaluation of materials systems beyond incremental improvements to fossil fuel-based polymers. Bioplastics, polymers derived from renewable biological feedstocks, biodegradable under defined conditions, or both, offer a chemically diverse and rapidly evolving platform for transitioning toward circular materials economies in which the value of carbon, energy, and material is retained across multiple use cycles. This review provides a comprehensive and critically organized account of the bioplastics field, spanning three generations of feedstock development from food crops through lignocellulosic residues to algae and waste streams; primary production pathways including microbial fermentation, ring-opening polymerization, and biosynthesis; forming processes from extrusion and injection molding to additive manufacturing; and the mechanical, thermal, and barrier properties that determine application fitness. Particular emphasis is placed on life cycle assessment, which reveals that bioplastics’ climate benefits are conditional on feedstock choice, land-use management, energy source at manufacturing, and end-of-life pathway, and that burden-shifting from greenhouse gas emissions to land use, water consumption, and eutrophication is a systematic risk requiring integrated LCA evaluation rather than single-metric optimization. The review further examines end-of-life recycling, composting, and biodegradation pathways; market applications across packaging, agriculture, automotive, biomedical, and electronics sectors; and the growing role of artificial intelligence and machine learning in accelerating materials design, process optimization, and lifecycle data management. Critical barriers to scale, such as cost premiums of 20–75% over conventional plastics, inadequate composting infrastructure, recycling stream contamination, regulatory fragmentation, and consumer labeling confusion, are systematically analyzed alongside mitigation strategies. The review concludes with a forward-looking discussion of emerging feedstocks, smart and functional bioplastics, and the policy and infrastructure investments required to translate the environmental promise of bio-based polymers into realized circular economy impact. Full article

Livestock farming is blamed for its significant carbon footprint (CF), contributing to environmental pollution and climate change. Among other approaches, this has highlighted the need to find alternative feeding systems for cattle production that are potentially able to reduce greenhouse gas (GHG) emissions. In this context, the objective of the present study was to compare the CF of producing cattle fed a Conventional diet versus cattle fed a diet that included vegetable by-products (VBP diet) sourced from the local agri-food industry. In this study, twenty-four entire male young bulls were reared in Navarra, Spain. Twelve calves were finished on the VBP diet that also included fodder and grain, and the remaining animals were finished with a local Conventional diet based on concentrate and straw. Results showed a larger CF of meat from animals fed the Conventional diet in comparison with the VBP-fed ones, that is, 117.84 kg versus 42.01 kg of CO₂ equivalent per kilogram of meat, respectively. This research demonstrates that using by-products from the local agri-food industry for feeding cattle has an important beneficial effect on the environment. It is not only a circular economy solution that recovers and recycles by-products instead of treating them as waste, but can also notably reduce the GHG associated with livestock production. This study marks the beginning of ongoing research into the effect of introducing regional vegetable by-products in the diet of livestock and their corresponding impacts on productivity and the environment, particularly in terms of GHG emissions per kilogram of feed consumed. Full article

Excessive N application in Camellia oleifera plantations exacerbates soil acidification and N₂O emissions, intensified by the input of Al-accumulating litter. Biochar is a promising amendment, yet how litter decomposition interacts with N and biochar to modulate acidification and greenhouse gas emissions remains unclear. To understand how decomposition of Al-accumulating litter interacts with N and biochar in the soil acidification process and gas emissions, a twelve-month laboratory incubation study was conducted using a fully factorial, three-factor completely randomized design to examine litter decomposition. The experimental factors included nitrogen fertilization, biochar amendment, and litter input level. The results showed that litter transiently activated biochar alkalinity, raising pH to 5.7–6.3, but subsequent organic acid release drove sustained re-acidification (ΔpH −0.4 to −0.5). This pH trajectory controlled denitrification: early high pH favored complete denitrification (nosZ > nirK), while later acidification inhibited N₂O reductase, boosting N₂O emissions under single litter and N. Litter-C primed native soil organic carbon, doubling cumulative CO₂ emissions. Biochar further elevated CO₂ emission rate by 7.6% under double litter input treatment via porous-microsite priming. These results demonstrated that litter quantity dictates a temporal switch from biochar alkali activation to organic acid overrun, creating an acid rebound that amplifies N₂O while sustaining CO₂ release. Optimizing litter retention and biochar application timing is essential to break the acid-N₂O feedback in intensively managed C. oleifera systems. Full article

This study investigates the influence of near-surface air temperature on the performance of internal combustion engines during mobile transects conducted in Mexicali, Baja California, Mexico, one of the hottest cities in North America. Field measurements were carried out along a 15 km urban transect on representative days in April, August, and February. Air temperature and relative humidity were recorded simultaneously at two engine air intake heights (0.66 m and 2.5 m), complemented by surface temperature data obtained from both in situ measurements and Landsat 8 thermal imagery. The results indicate that near-surface air temperature exhibits considerable spatial and temporal variability and is closely associated with land surface temperature (LST) patterns derived from satellite observations. The correction factor (Cf), used to quantify the combined effects of air temperature and atmospheric pressure on engine performance, showed that extremely high temperatures (approaching 50 °C) may reduce engine performance by up to 3.35% relative to standard test conditions. Conversely, cooler winter conditions may improve engine performance by approximately 4.6%. These results suggest that vehicle operation under extremely hot climatic conditions may deviate from the standardized assumptions adopted by the Intergovernmental Panel on Climate Change (IPCC) for emission factor estimation. This study contributes to a better understanding of the effects of extreme urban heat on vehicle performance and demonstrates that localized thermal conditions may influence the assumptions commonly used in vehicle emission assessments. The findings provide valuable information for improving greenhouse gas emission inventories and support evidence-based climate adaptation and urban planning strategies in arid cities. Full article

Higher education institutions are increasingly expected to reduce greenhouse gas emissions while maintaining reliable educational, laboratory, and administrative operations. This challenge is particularly relevant in transition economies, where university campuses often depend on fossil-fuel-based electricity systems, natural-gas heating, and aging infrastructure. This study presents a campus-scale decarbonization assessment for the Tashkent Institute of Chemical Technology in Uzbekistan. The quantified inventory covered Scope 1 emissions from natural-gas combustion and Scope 2 emissions from purchased electricity. Paper use, digital services, behavioural measures, and campus greening were assessed as supplementary institutional indicators and were excluded from the quantified total because consistent pre- and post-intervention activity data were unavailable. The assessment combined institutional utility records for 2023–2025 with information on renewable-energy deployment, heating modernization, digital transformation, sustainability awareness, and campus greening. A 300 kW solar photovoltaic system comprising 666 modules was commissioned in May 2023, with a documented annualized generation potential of approximately 520,000 kWh. Purchased grid electricity amounted to 711,402, 745,947, and 749,060 kWh in 2023, 2024, and 2025, respectively, while annual natural-gas consumption was 144,775, 161,200, and 142,031 m³. Using a conservative standard-based net calorific value of 31.8 MJ/m³ together with IPCC stationary-combustion factors, annual Scope 1 and Scope 2 emissions were estimated at 637.53, 685.29, and 652.65 tCO₂-eq, respectively. The 2025 total was 4.76% below the 2024 value but 2.37% above the 2023 value. The annualized PV technical potential corresponds to a theoretical maximum Scope 2 displacement of 276.64 tCO₂-eq/year under 100% self-consumption. This value does not represent measured generation or a realized emission reduction and was not included in the quantified inventory. Digitalization, behavioural engagement, and greening were evaluated as complementary measures rather than assigned separate emission-reduction credits. The study provides a transparent and regionally relevant framework for universities in transition economies seeking to strengthen campus carbon management under incomplete data conditions. Full article

In the context of increased international efforts to reduce greenhouse gas emissions through various measures included in climate agreements, regulatory frameworks, and decarbonization strategies, the utilisation of renewable energy resources represents a solution to sustainable global development. Wave energy is a marine renewable resource that has great potential but has not yet been fully exploited. Considering this, the current work examines the Black Sea’s wave climate variability and wave energy dynamics using SWAN model results applied throughout the basin. Attention is given to the long-term assessment of wave conditions and wave power, the characterization of dominant wave patterns, and the identification of possible changes in sea state parameters over an extended period (30 years). Recent wave climate variability and projections of future changes under the RCP4.5 and RCP8.5 climatic scenarios are evaluated. The assessment of the potential effects of climate change on sea state conditions and the spatial distribution of wave energy resources in the Black Sea basin is performed by comparing the historical and future projections, thereby also facilitating the observation of climate change pattern evolution. The results offer a forward-looking assessment of wave energy potential in the Black Sea and its reliability as a sustainable energy resource in relation to climate change. Full article

The whole pavement life cycle is divided into five phases: raw material production, construction, service use, maintenance and rehabilitation, and end-of-life (EOL). Distinct system boundary definitions (cradle to gate, cradle to site, cradle to grave) are clearly distinguished, and two categories of vehicle-related emissions are strictly differentiated: baseline vehicle operation emissions (excluded) and pavement-induced incremental emissions (included only for full cradle-to-grave accounting). According to cited highway pavement inventory data (functional unit: 1 m² full cross-section composite pavement, cradle-to-gate material-only boundary), cement-related materials account for merely 4.7% of total structural material mass yet contribute over 84.5% of material-phase carbon emissions, while asphalt mixture construction emissions generally make up less than 10% of mixing-stage outputs. In the use phase, pavement deformation, rolling resistance elevation and surface texture loss trigger extra vehicle fuel consumption and associated greenhouse gas increments. Maintenance-stage emissions stem from repair material manufacturing, on-site machinery operation and traffic congestion delays during lane closure; milling, transportation and recycling dominate EOL carbon outputs. This review further classifies all emissions into direct engineering emissions and pavement-derived indirect emissions, compares carbon performance and service-life extension effects of eight mainstream maintenance strategies, and thoroughly decomposes milling, stockpiling, haulage and recycling links of waste asphalt, alongside multiple environmental burden allocation methods for reclaimed asphalt pavement (RAP). A full spectrum of green low-carbon technologies is summarized, including biochar bio-materials, RAP, crumb rubber, industrial byproducts, warm-mix asphalt (WMA), cold recycling and CCUS negative-carbon materials. We also balance their emission reduction benefits against potential deterioration risks to rutting resistance, fatigue life and moisture stability. Combined with a life-cycle cost assessment (LCCA), this study analyzes cost-emission trade-offs of all technical routes, and deeply discusses multi-source uncertainty, sensitive input parameters and universal methodological limitations of pavement LCA. Core takeaways indicate that raw material production and long-term service use are the two dominant carbon emission stages; a medium RAP-WMA combination and cold in-place recycling represent the most economically and environmentally balanced mitigation solutions. Major research gaps and targeted future research directions are proposed, providing standardized theoretical support and dual environmental–economic decision references for low-carbon asphalt pavement design and full-life carbon accounting. Full article

During forest exploitation, large amounts of wood biomass are left as residues after harvesting, even though this material could be valuable in reducing greenhouse gas emissions by replacing fossil fuels and serving as a source of bioactive compounds. Within the context of the European Union’s circular bioeconomy strategy, enhancing the efficacy and rational application of forest logging residues constitutes a critical future objective. To evaluate the possible use of the stumps as forest residue-derived woody biomass for the first time, the chemical composition and presence of bioactive compounds in the xylem and bark of F. angustifolia Vahl. ssp. pannonica Soó & Simon stumps were analyzed, including the content of cellulose, acid-insoluble lignin, acid-soluble lignin, ash, and extractives soluble in toluene–ethanol and hot water. In hot water extracts, total phenolic content, the antioxidant activity determined by scavenging capacity toward DPPH and HPTLC, the content of elements by ICP-OES, and the identification of bioactive compounds by UHPLC-DAD-ESI MS/MS were assessed. Considering the chemical composition, the quality of the xylem of the F. angustifolia (cellulose: 42.46 ± 0.45%; lignin: 25.05 ± 0.02%; hemicelluloses: 19.74 ± 0.46%) was similar to that of the stem. Hot water extracts of the bark of F. angustifolia stumps showed high total phenolic content (33.94 ± 1.43 mg GAE/g DW) and strong antioxidant potential (198.48 ± 3.33 μmol TE/g DW), while toxic metals were not detected. UHPLC-DAD-ESI-MS/MS analysis indicated phenylethanoid glycosides as the dominant compounds in the extracts. The analyzed stumps of Fraxinus angustifolia Vahl. in the “Morović” Forest Administration represent a valuable biomass with potential for further valorization. Full article

Anthropogenic greenhouse gases (GHGs) and emissions from maritime transport represent a significant challenge for atmospheric monitoring and control. The Istanbul Strait, characterized by its narrow, winding geography and high traffic density, presents a unique chokepoint where these emissions directly impact local air quality. This study proposes a gas-focused integrated framework that combines Sentinel-5 Precursor (Sentinel-5P) TROPOspheric Monitoring Instrument (TROPOMI) satellite observations with Automatic Identification System (AIS) data to analyze atmospheric trace pollutant time series in the Istanbul Strait during 2025. A bottom-up emission methodology based on the IMO 4th GHG Study was employed, yielding annual gaseous pollutant totals of 213,678 tons of carbon dioxide (CO₂), 5970 tons of nitrogen oxides (NO_x), and 686 tons of sulfur oxides (SO_x). Time-series and cross-correlation analyses demonstrated a quantifiable relationship between AIS-derived NO_x estimates and TROPOMI NO₂ tropospheric column densities (r = 0.76, p < 0.05, n = 12), validating the use of satellite sensors for marine atmospheric monitoring. A decision support system (DSS) proof of concept (PoC) was developed to evaluate emission control scenarios through speed optimization. The results indicate that implementing a 10% speed reduction strategy could reduce CO₂ emissions by 18% (38,462 tons) and generate net economic savings of EUR 3.07 million under the European Union Emissions Trading System (EU ETS) carbon pricing framework. Furthermore, a scenario with a 20% speed reduction resulted in a 35% decrease in CO₂ emissions. The findings underscore the potential of integrating satellite-based gas remote sensing with AIS data, thereby facilitating real-time atmospheric monitoring and strengthening emission control policy enforcement in maritime chokepoints. Full article

Air travel induces substantial landside traffic through the movement of passengers, employees, suppliers, and cargo between airports and their surrounding regions. While this airport-induced landside traffic has received growing attention within airport sustainability research, its associated external costs remain insufficiently quantified. This study develops a modular model to estimate traffic volumes and associated external costs of airport-induced landside traffic. It accounts for key behavioral and operational parameters, including modal split, trip distances, occupancy rates, and trip frequencies, differentiated across user groups and transport modes. The model is applied to Germany as a case study using national mobility statistics, airport data, and external cost factors from European transport studies. The assessment covers greenhouse gas emissions, air pollution, accidents, noise, habitat damage, and upstream fuel supply impacts. Results indicate that airport-induced landside traffic generated external costs of approximately EUR 1.43 billion in Germany in 2019, with passengers and airport employees accounting for the largest shares. Accident costs and greenhouse gas emissions dominate the overall impacts. Sensitivity analyses further show that moderate behavioral changes, such as modal shifts toward public transport and increased vehicle occupancy, can significantly reduce external costs. The findings highlight the importance of integrating landside access into environmental assessments and sustainable airport planning. Full article

The ongoing European energy transition and the restructuring of energy markets are increasing pressure on energy-intensive industries to reduce greenhouse gas emissions while maintaining secure and reliable energy supplies. In this context, local geothermal resources represent a promising low-carbon energy source for strengthening industrial energy resilience. This study investigates the geothermal potential of a heavy industrial area located at the northwestern margin of the Bohemian Massif (Czech Republic), where elevated heat flow is associated with the interaction of Variscan structures, post-orogenic magmatism, and Cenozoic rifting. Due to safety restrictions related to industrial infrastructure, including pipelines and zones with explosive substances, a combination of controlled-source magnetotellurics and gravimetric surveying was applied. Magnetotelluric measurements conducted in the frequency range of 8–8192 Hz identified a major fault-controlled boundary between the crystalline basement of the Saxothuringian Zone and the Neogene sedimentary fill of the Most Basin. Gravimetric modeling revealed a pronounced negative residual Bouguer anomaly that can be explained by variations in sediment thickness and/or the presence of a low-density body within the crystalline basement. The integrated interpretation of geophysical data, regional heat-flow distribution, and existing geological knowledge suggests that this low-density body may be associated with granite porphyry intrusions of the Altenberg–Teplice Collapse Caldera. The results indicate that the northwestern Bohemian Massif contains geological structures favourable for geothermal exploration and demonstrate the applicability of low-impact geophysical methods in complex industrial environments. The study provides a scientific basis for future geothermal development aimed at supporting industrial decarbonization, regional energy resilience, and long-term energy security. Full article

Feed efficiency classification based on residual feed intake (RFI) and residual intake and gain (RIG) is widely used to identify biologically efficient animals, yet it remains unclear whether this classification reflects consistent differences in digestive, fermentative, and metabolic processes. This study evaluated the effects of RFI and RIG classification on nutrient intake, apparent digestibility, ruminal fermentation, nitrogen metabolism, microbial protein synthesis, and gaseous emissions in confined lambs. Thirty-eight weaned Texel ewe lambs underwent a 60-day performance test using an automated feed intake system and were classified as high-efficiency, neutral, or low-efficiency based on both indices. Animals were individually housed in respirometric chambers where emissions of methane, carbon dioxide, nitrous oxide, and ammonia were assessed by cavity ring-down spectroscopy; apparent digestibility was determined from total collections of feed, orts, faeces, and urine; microbial protein synthesis was estimated from urinary purine derivatives; and ruminal short-chain fatty acid profiles were determined by gas chromatography. Feed efficiency classification did not significantly affect body weight, nutrient intake, apparent digestibility, ruminal fermentation parameters, nitrogen balance, microbial protein synthesis, or greenhouse gas emissions. Principal component analysis revealed two major biological gradients related to nutrient intake and utilisation (42.9%) and ruminal fermentation and gaseous emissions (23.3%), together explaining 66.2% of total variance, but showing no clear separation among efficiency groups. These findings indicate that the digestive, fermentative, and nitrogen metabolism variables evaluated in this study did not account for the observed variation in feed efficiency. Because the regression underlying RIG explained little additional variation (R² = 0.01), these conclusions primarily reflect feed efficiency as classified by RFI, suggesting that other physiological mechanisms may play a more important role in determining feed efficiency in confined Texel ewe lambs. Full article

Environmental sustainability of natural and synthetic fibers used in textiles and composites depends on their impacts throughout production, use, and end-of-life (EoL) stages. Natural fibers are renewable and biodegradable but may require substantial water and agricultural inputs, whereas synthetic fibers contribute to fossil resource depletion, microplastic pollution, and persistent waste generation. Natural fibers are often regarded as more sustainable alternatives to synthetic fiber; however, evidence from a life cycle assessment (LCA) reveals a more nuanced reality. As demand for fiber-based materials increases across textile and composite applications, a deeper understanding of the environmental implications of both natural and synthetic options becomes essential. This review compares these fiber categories from a life cycle perspective, examining carbon footprint, energy demands, resource consumption, and EoL pathways. Natural fibers such as cotton, flax, jute, hemp, sisal, banana, coir, and emerging plant-based alternatives offer advantages including biodegradability and carbon sequestration during cultivation. Nevertheless, agricultural practices and subsequent industrial processing require substantial land, water, and chemical inputs. Synthetic fibers, predominantly derived from fossil resources, provide a long service life and consistent performance but are associated with high greenhouse gas (GHG) emissions, dependence on non-renewable feedstocks, microplastic pollution, and broader environmental impacts. By presenting a comprehensive life cycle-based comparison, this review identifies the conditions under which each fiber type may offer environmental benefits, supporting informed material selection for sustainable development. Full article

Road transport is a major contributor to greenhouse gas (GHG) emissions, representing a significant challenge when it comes to achieving climate goals. Although methodologies such as Activity–Structure–Intensity–Fuel (ASIF) are widely used to estimate transport emissions, their application as regulatory instruments remains unexplored. This study addresses this gap by proposing a framework that operationalizes ASIF for managing Scope 3 emissions in toll-road concessions. Using operational and traffic data from a major Brazilian highway concession, baseline emissions are compared with intervention scenarios involving the adoption of initiatives such as free-flow tolling and fleet electrification. The results demonstrate that emission reductions can be associated with specific ASIF components and can be translated into measurable contractual indicators. In the case study, the implementation of free-flow tolling reduced emissions at toll plazas by up to 37%. Fleet electrification, which is now limited by the charging capacity of roads, can be improved and have its effects captured by the framework so that actions resulting from the concessions made to improve availability can enable policies aimed at reducing total user-related emissions. The study is the first, to the best of the authors’ knowledge, to operationalize the ASIF methodology as a governance and contractual instrument for Scope 3 emissions management in highway concessions in Brazil. By bridging emissions estimation and concession governance, it provides a practical framework for incorporating Scope 3 mitigation targets into concession contracts and climate-oriented transport regulation. Full article

The production of hot mix asphalt (HMA) is energy-intensive, resulting in carbon dioxide (CO₂) and greenhouse gas (GHG) emissions. The primary energy source (accounting for over 97%) and emissions source is the rotary drum employed for the drying and heating of the aggregates. Quantifying the CO₂ emissions associated with combustion is of crucial importance in order to facilitate a more profound comprehension of the environmental impacts of HMA production. The objectives of this study are to develop a methodological framework for the quantification of combustion-related carbon dioxide emissions in the context of asphalt production. The proposed framework investigates three complementary approaches: (i) an energy-balance-based thermal energy (TE) model, (ii) recordings of fuel consumption and (iii) direct measurement of exhaust-gas composition. By applying these methods in parallel and cross-comparing their results batch by batch, the framework enables reliable verification of actual CO₂ emissions from the module A3—production stage of asphalt manufacturing. In this stage, the predominant source of greenhouse gases is fuel combustion during aggregate drying and heating. A comprehensive set of data was collected from two HMA batch plants, each operating under distinct conditions. The parameters considered included fuel type, asphalt mixture type, asphalt production time, aggregate moisture content, mixing temperature, and production rate. The TE model demonstrated a robust linear correlation with measured energy consumption (R² = 0.97), and fuel-based CO₂ estimates exhibited minimal discrepancy compared to direct exhaust-gas measurements on average (mean difference 1.0%; t-test p = 0.674). However, systematic discrepancies were observed between the two plants (with overestimation of up to 20% at one plant (AP1) and underestimation of up to 12% at the other (AP2)). This demonstrates that energy-based CO₂ estimation methods require plant-specific calibration against direct measurement before they can be reliably applied in life cycle assessment (LCA) and environmental product declaration (EPD) practice. Measured CO₂ emission intensities ranged from 17.39 to 21.76 kg/t at AP1 and from 16.05 to 18.44 kg/t at AP2; the casing-losses factor of the TE model was calibrated to CL = 23% for the studied diesel-fired plants (mean deviation +0.4% from measured energy); and aggregate moisture content explained 74% of the variance in measured energy consumption (R² = 0.743). Full article