Search Results (3,722)

Although digital transformation is increasingly regarded as a vital pathway toward corporate decarbonization, its environmental impacts can spread beyond the boundaries of the undergoing firms. This study explores whether digital transformation implemented by focal firms affects the carbon emission intensity of their upstream suppliers and downstream customers. Using data from Chinese A-share-listed companies over the period of 2009–2023, we find that focal firms’ digital transformation significantly reduces the carbon emission intensity of upstream and downstream partners. Supply chain concentration and partner digitalization partially mediate this relation, indicating that changes in supply chain structure and the diffusion of digital capabilities constitute important channels through which carbon reduction effects are transmitted. The effect is stronger for partners with higher total factor productivity, demonstrating that the efficacy of digital spillovers depends partly on firms’ productive efficiency and absorptive capacity. Further analysis shows that such effects are more prominent with heavily polluting industries, among smaller firms, and in industries with weaker competition. The results remain robust to alternative variable measurements, model specification, and treatments for potential endogeneity. These findings show that digital transformation generates environmental spillovers through vertical supply chain relationships and highlight the role of focal firms in facilitating supply chain carbon emission reduction. Full article

International oil price volatility poses severe risks to macroeconomic stability and energy security, presenting complex policy challenges for China as it simultaneously pursues economic growth and a low-carbon transition. To bridge the gap between general equilibrium reallocation and transition quality, this study couples an 18-sector recursive dynamic computable general equilibrium (CGE) model with a super-efficiency slacks-based measure (SBM) model to evaluate China’s macroeconomic path and green total factor productivity (GTFP) from 2023 to 2045. We simulate a permanent 200% international oil price shock starting from 2026—conceived as a tail-risk stress test—together with alternative shock scenarios of varying magnitude and persistence (P50, P100, and a five-year temporary variant of P200_5Y), and evaluate four counterfactual policies under the P200 stress-test condition: household transfers (Tran_HG), price regulation (P_REG), structural tax reduction (T_RED), and energy-transition acceleration (Delta_ENE). The shock triggers imported cost-push inflation and a regressive shift toward coal, with the long-run damage governed jointly by shock magnitude and persistence; since GTFP deteriorates monotonically with shock size, the apparent emission reductions under extreme shocks suggest a contraction-driven “efficiency illusion” rather than genuine green improvements. Individually, P_REG and T_RED are effective only as temporary shields, Tran_HG provides the strongest welfare protection but amplifies the high-carbon rebound, and Delta_ENE uniquely improves resilience and green efficiency simultaneously. Building on these results, a combined policy package (COM) is further designed and simulated, which exhibits positive complementarities; it cuts the 2026 GDP loss by about 70%, turns GDP and welfare losses into net gains by 2043 and 2040, respectively, and delivers favorable green-transition outcomes. These findings call for coordinated, phased policy packages in which fiscal space rotates from emergency shields to demand-side repair and, ultimately, to electrification-led structural transformation. Full article

To clarify the effects of biomass char injection position on combustion characteristics and NO formation, a three-dimensional CFD model of a 300 MW tangentially fired pulverized coal boiler was developed using ANSYS Fluent. The Realizable k-ε model, discrete phase model, species transport model, and P-1 radiation model were employed to describe the flow, combustion, heat transfer, and NO formation processes. The model was validated against field measurements under pure pulverized coal combustion conditions. Based on the validated model, five co-firing cases were designed by injecting biomass char through primary air nozzles located at five different elevations in the burner zone. The results show that biomass char injection position significantly affects furnace flow organization, heat release distribution, carbon conversion, and NO formation, while maintaining the overall tangential swirling structure. Case C achieved the highest outlet velocity of 10.42 m/s, which was 9.1% higher than that of Case E, and exhibited the lowest CO concentration, indicating improved carbon conversion performance. However, the intensified oxidation environment in Case C promoted fuel-N conversion and resulted in the highest NO concentration of 313 ppm. Case B achieved the highest outlet temperature of 1429 K, which was 6.8% higher than that of Case E. In comparison, Case D maintained a similar CO₂ mole fraction of 0.1546 to Case C, which was 0.1545, while reducing the NO concentration from 313 ppm in Case C to 145 ppm, corresponding to a reduction of 53.7%. Therefore, Case D achieved the most favorable balance between carbon conversion and NO emission control under the investigated conditions. This study demonstrates that biomass char injection position is an important operational parameter for optimizing biomass utilization and reducing NO emissions in tangentially fired pulverized coal boilers. Full article

Improving the low-carbon operational performance of wastewater treatment facilities (WWTFs) is important for coordinated pollution reduction and carbon mitigation in China. The interprovincial carbon emission efficiency (CEE) of WWTFs reflects both the low-carbon performance of regional wastewater governance systems and cross-regional linkages shaped by technology diffusion, governance experience, and spatial adjacency. Using operational data from WWTFs in 30 provincial-level regions of China from 2010 to 2023, this study first measures provincial CEE with a super-efficiency slack-based measure (SBM) model incorporating undesirable outputs. It then integrates a modified gravity model, social network analysis, and the quadratic assignment procedure (QAP) to examine the evolution, structure, and formation mechanisms of the association network. The results show that the CEE of provincial WWTFs remained below the efficiency frontier overall, with periodic fluctuations and persistent structural differences. The model-inferred association network first contracted and then expanded, showing dense connections in eastern and central China and sparse connections in the northwest. Its node structure evolved from a dispersed multicore pattern to hub-centered concentration and then back toward a multicore configuration, while inter-block linkages showed a hierarchical transmission structure involving core spillovers, absorptive transmission, and peripheral reception. The QAP results indicate that interprovincial adjacency is the most stable correlate of network formation, whereas differences in technological innovation and capacity utilization show only stage-specific associations. These findings suggest that the CEE of WWTFs is not only a local performance outcome, but also a relational outcome shaped by regional linkages and structural positions. Therefore, low-carbon governance of WWTFs should move beyond single-region efficiency improvement and place greater emphasis on cross-regional collaboration, role-specific policy design, and leadership by core regions. Full article

Research Highlights: This study quantifies aboveground biomass for Oreopanax oroyanus and Escallonia resinosa in an Andean relict forest and examines their conservation relevance related to the scale of emissions voluntarily reported by small corporate emitters. Background and Objectives: Andean relict forests face severe fragmentation and degradation. This research evaluates carbon stocks in the Bosque de Zárate Reserved Zone (Peru) and explores how these findings may inform climate mitigation and conservation initiatives by examining their potential alignment with emissions voluntarily reported by Peruvian firms participating in a carbon disclosure system. Materials and Methods: A total of 27 plots were evaluated between 3034 and 3200 m a.s.l., tree height and diameter (DBH ≥ 10 cm) were measured for key species, and biomass was estimated using a pantropical allometric equation. Landsat imagery (1985–2025) was analyzed to assess long-term vegetation conditions, while Dynamic World land cover and Sentinel-1 radar (2018–2025) were used to assess forest cover and canopy structure changes. Voluntarily reported emissions of Peruvian firms participating in the “Carbon Footprint Peru” system (2012–2024) were analyzed to contextualize the forest results in the potential corporate interest in climate mitigation in Peru. Results: Total aboveground carbon stock for the altitudinal belt in the study area was 919.4 Mg C (18.6 Mg C ha⁻¹), equivalent to 3374.2 Mg CO₂, with Escallonia resinosa accounting for approximately 71% of the estimated stock. Multi-decadal satellite observations indicated persistent forest cover within the evaluated belt, while analysis of voluntarily reported corporate emissions identified numerous service-sector firms with annual emissions below 100 Mg CO₂ eq, providing context for the potential scale of future conservation-financing initiatives. Conclusions: Relict forests offer relevant localized carbon storage linked to other ecosystem services. Providing field-based carbon data may support the development of locally relevant community-led initiatives meaningful to climate-financing initiatives. However, the existing carbon stock does not by itself represent a source of carbon credits, and carbon capture-specific studies would need to be implemented to fully assess the mitigation capacity of these ecosystems. Full article

The prevention of coal mine fires and the sequestration of CO₂ represent two grand challenges that have traditionally been addressed separately. Here we report a CO₂-modified bentonite-based sealing material that concurrently achieves fire resistance, gas sealing and mineral-carbonation CO₂ uptake through rational materials engineering. In this work, “carbon-negative” is used as a comparative property: the material’s cradle-to-gate embodied emissions combined with its measured 28-day mineral uptake are lower than the cradle-to-gate footprint of a conventional cement-based benchmark under the stated system boundary. High-pressure CO₂ intercalation expanded the montmorillonite d-spacing from 12.48 to 14.79 Å and introduced carbonate functional groups (1435 cm⁻¹), as confirmed by FTIR and XRD. Systematic optimization of a bicomponent formulation incorporating municipal solid waste incineration slag and CO₂-saturated zeolite yielded a material with 28-day compressive strength of 37.9 MPa, a fire resistance limit of 186 s and O₂ reduction from 13.7% to 4.9%. Notably, carbon sequestration reached 24–40 kg CO₂ per ton through mineral carbonation, validated by carbonate peaks in FTIR and calcite detection in XRD. Carbon accounting based on a cradle-to-gate inventory (342–408 kg CO₂-eq/t) combined with the measured 28-day mineral uptake (24–40 kg CO₂/t) yields a comparative net balance of −46 to −188 kg CO₂-eq/t relative to a conventional cement-based benchmark under the stated system boundary. The synergistic mechanism involves CO₂-modified bentonite-regulating layer spacing, alkali-activated slag releasing Ca²⁺/Mg²⁺ for carbonate precipitation, and zeolite providing endogenous carbon slow-release. This work establishes a materials-chemistry paradigm for transforming industrial waste streams into functional carbon sinks while addressing critical mining safety needs. Full article

Against the global transition toward sustainable development, firms are increasingly integrating environmental, social, and governance (ESG) principles into their business strategies. This study develops a conceptual framework linking digital servitization to ESG performance and examines the underlying mechanisms and heterogeneous effects. Using 4686 firm-year observations from Chinese A-share listed firms in heavily polluting industries during 2013–2024, we construct a text-based measure of digital servitization through text mining and Python 3.13’s Jieba word-segmentation function. The empirical results show that digital servitization significantly improves firm ESG performance. The mechanism analyses indicate that carbon emission reduction and information transparency partially mediate this relationship. The quantile regression results further show that the positive effect of digital servitization is stronger at higher conditional quantiles of ESG performance, suggesting a possible cumulative advantage pattern. The heterogeneity analyses reveal that the effect is significantly stronger for non-high-tech firms than for high-tech firms, whereas the difference between state-owned and non-state-owned firms is not statistically significant. These findings extend the literature on digital servitization and ESG performance and provide practical implications for firms and policymakers seeking to promote sustainable development in the digital era. Full article

As the construction industry seeks to reduce carbon emissions, timber has emerged as a key material due to its capacity for biogenic carbon storage and end-of-life (EoL) reuse. However, assessing the practical circularity potential of timber structures remains challenging. This is largely because recovered components suffer geometric and material losses at their connection points. This study evaluates the EoL reuse and recycling potential of a multi-storey timber building by combining Building Information Modelling (BIM) with Life Cycle Assessment (LCA). A digital model was used to quantify structural elements (beams, columns, and walls), explicitly accounting for material losses at connections to calculate the net recoverable timber. The recovered material (837.39 m³) was assigned to various cascading use scenarios based on material strength: structural reuse, non-structural reuse, engineered wood production, and energy recovery. To align with ISO 14044 principles, a functional equivalence factor (Q-factor) was applied to measure the environmental benefits of substituting new materials. Results indicate an overall material loss of 16.62% due to connections. Among the evaluated EoL pathways, structural reuse yielded the greatest net carbon benefit (−128.7 tCO₂e), significantly outperforming lower-value alternatives such as energy recovery (−29.3 tCO₂e). Additionally, a Design for Disassembly (DfD) sensitivity analysis showed that reducing connection losses by 50% could increase net global warming potential (GWP) savings by up to 19.7%. In conclusion, connection design is a critical factor in enabling timber circularity. Furthermore, combining BIM material tracking with LCA methods offers a practical approach to quantifying the long-term carbon benefits of timber reuse strategies. Full article

Airborne viral transmission necessitates effective indoor air purification strategies. Conventional methods often face operational challenges, including potential secondary aerosolization and performance degradation under high-humidity conditions. This study evaluates a hybrid control system integrating a multi-walled carbon nanotube (MWCNT) field-emission plasma with a UV-LED/TiO₂ photocatalyst to continuously inactivate airborne bacteriophages. The system’s performance was assessed under varying applied voltages and relative humidity (RH) levels. The kinetic results demonstrated that the hybrid configuration yields a synergistic inactivation effect compared to the isolated plasma or photocatalytic treatments. Based on the kinetic enhancement, it is hypothesized that trace ozone generated by the plasma discharge serves as an electron acceptor on the UV-illuminated TiO₂ surface, thereby mitigating electron–hole recombination and enhancing the generation of hydroxyl radicals (·OH). Furthermore, the hybrid system exhibited operational resilience under high-moisture conditions, maintaining a robust active inactivation constant (k_a = 0.190 min⁻¹) at 70% RH without statistical degradation. This stability indicates that the continuous field emission effectively utilizes ambient moisture for secondary radical generation rather than being quenched by water condensation. Ultimately, this hybrid technology presents a continuous and adaptable engineering control measure for mitigating airborne pathogens in enclosed occupational environments, including those in high-humidity climates. Full article

The economic and social development of coal resource-exhausted cities (CRECs) depends heavily on coal resources. Measures to improve the carbon emission efficiency (CEE) of CRECs are urgently needed because this development path, characterized by high resource dependence, inevitably generates substantial carbon emissions. However, there has not been much focus on the spatial spillover effects and regional heterogeneity of CEE in these cities. To address this gap, this study selects 37 Chinese CRECs as research subjects. It comprehensively evaluates the static characteristics and dynamic changes in these cities’ CEE from 2011 to 2023 using the SBM-DDF model and the GML index. It then employs the spatial Durbin model to identify key influencing factors of CEE. According to the empirical results, the average CEE of the sample cities did not reach the production frontier, generally remaining at a moderate level and fluctuating. The main factor driving CEE growth for CRECs in all regions is technological progress. CRECs in the western region had the greatest growth in CEE (0.71%), followed by the northeastern (0.36%) and central (0.05%) regions, while the growth in CEE remained unchanged in the eastern region. The local CEE grew by 0.286 units for every unit increase in CEE in neighboring cities, demonstrating the spillover effects essential for regional sustainability. There is significant regional heterogeneity in the influencing factors of CEE in China’s CRECs, necessitating tailored sustainable development strategies. Full article

The digitalization and intelligent transformation of transportation have emerged as technological solutions for enhancing traffic efficiency and reducing traffic-related pollutants. However, existing studies primarily focus on traditional traffic emission reduction measures, and there is limited empirical evidence demonstrating how the digitization and intelligence of road infrastructure can reduce carbon dioxide emissions and air pollutants. To address this research gap, this study employed a difference-in-differences methodology to investigate the causal effects of the Smart Highways Pilot (SHP) policy on carbon emission intensity (i.e., CO₂ emissions per unit of GDP) and air pollution (i.e., PM_2.5 concentrations), using data from 272 Chinese cities spanning 2012 to 2023. Our estimation results demonstrate that the implementation of the SHP policy led to an average reduction of about 4.7% in CO₂ emissions per unit of GDP and a 5.1% decrease in PM_2.5 concentrations, translating to an average annual abatement of approximately 707,008 tons of CO₂ and a 2.204 μg/m³ drop in PM_2.5 concentrations among the sample pilot cities. Furthermore, the carbon reduction and pollution mitigation effects of the SHP policy were more pronounced in regions emphasizing pilot themes, such as infrastructure digitalization and vehicle–road collaboration, cities promoting new-energy vehicles, and eastern regions. This study provides robust causal evidence for policymakers to assess the synergistic carbon abatement and pollution reduction benefits of SHP policies, while contributing to the literature on smart transportation and sustainable development, and offering valuable insights for other countries and regions on building green, low-carbon transportation systems through the digitalization and intelligent upgrading of road infrastructure. Full article

Cities are confronted with heat, drought, and pluvial flooding, highlighting the need for renovation strategies that enhance climate resilience while minimizing greenhouse gas emissions. This research developed an integrated assessment framework to quantify the mitigation potential of urban and building surface components using five area-based key performance indicators (KPIs): Surface Heat Contribution (SHC), Flood Mitigation Factor (FMF), Water Storage Capacity (WSC), Evaporation Volume (EVA), and Global Warming Potential (GWP). The framework combines simplified life-cycle assessment with biophysical models for heat, water storage, and evaporation, designed as an accessible complement to 3D microclimate tools. Applied to an exemplary residential area in Daegu, South Korea, the method benchmarks existing surfaces and evaluates renovation scenarios targeting heat reduction, flood mitigation, and drought resilience. Results show that surface renovation measures improve mitigation potential. The performance varies across KPIs, involving trade-offs with embodied emissions. Optimal outcomes arise from balanced hybrid strategies integrating complementary measures. Selective greening combined with low heat capacity, high-conductivity materials (e.g., metal façades) effectively reduces heat stress but increases embodied GWP and structural demands. Permeable and greened surfaces improve WSC and EVA, supporting short-term flood mitigation, yet reveal limitations under prolonged rainfall. The proposed framework supports transparent and low-carbon climate-resilient renovation decision-making. Full article

Power transmission and transformation projects involve substantial quantities of engineering materials and key equipment with significant embodied carbon emissions, yet project-level carbon accounting methods remain insufficiently tailored to power engineering practices. This study takes a 110 kV transmission and transformation relocation project as a case study and develops a bill-of-quantities-based life-cycle carbon emission accounting method. The accounting scope covers civil engineering materials, cable systems, gas-insulated switchgear (GIS), and other key engineering components, and the carbon reduction potential of low-carbon material and equipment substitution is further evaluated. The proposed framework integrates engineering decomposition, hierarchical mapping from bill-of-quantities items to material and equipment inventories, component-level carbon factor modeling, carbon factor consistency calibration, and carbon-cost dual-objective scenario analysis. A cradle-to-grave boundary is adopted, covering material production (A1–A3), transportation (A4), construction (A5), operation and maintenance (B), and end-of-life treatment with recycling credits (C). Compared with conventional project-level carbon accounting that first aggregates engineering quantities into a flat material list, the proposed method preserves the bill-of-quantities hierarchy during inventory translation and assigns life-cycle modules at the item-to-component conversion step. This improves traceability from engineering packages to carbon hotspots and makes the accounting results more directly usable for procurement-oriented low-carbon decisions. The baseline case yields a net life-cycle carbon footprint of 455.5 t CO₂e, with material production contributing 305.2 t CO₂e (67.0%) and operation and maintenance contributing 147.2 t CO₂e (32.3%). At the component level, 110 kV XLPE cables and SF₆-related impacts dominate, accounting for 31.8% and 27.1% of the total, respectively. Individual substitution measures reduce emissions by 3.1–16.5%, while the combined strategy lowers the footprint to 355.8 t CO₂e, achieving a 21.9% reduction with a 7.2% cost increase. The results demonstrate that the proposed method can effectively translate engineering quantity documents into traceable project-level life-cycle carbon accounting results, providing support for low-carbon material selection, equipment procurement, and early-stage decision making in 110 kV transmission and transformation relocation projects. Full article

Conventional solvent-based and hot-melt road marking paints face significant challenges regarding high volatile organic compound (VOC) emissions and limited durability, necessitating the development of eco-friendly, high-performance alternatives. In this study, a waterborne acrylic road marking paint was systematically formulated and optimized using an L₁₆(4⁵) orthogonal experimental design coupled with a comprehensive weighted scoring method integrating subjective and objective (entropy) weights. Four key formulation parameters (pigment-to-binder ratio, titanium dioxide content, ground calcium carbonate content, and coalescing agent dosage) were investigated, with abrasion resistance, hiding power, luminance factor, and stain resistance as evaluation criteria. The optimized formulation was identified through range analysis of comprehensive scores and subsequently subjected to rigorous performance characterization, including retroreflectivity optimization, Taber and accelerated abrasion testing, UV-accelerated weathering, skid resistance, and VOC emissions measurement using a self-designed sealed chamber system. Benchmark comparisons against commercial waterborne and hot-melt paints demonstrated that the developed formulation achieves superior abrasion resistance, exceptional weatherability, and meaningfully lower VOC emissions. Field application on an operational highway section in Liaoning Province, China, confirmed the practical constructability and performance reliability of the optimized paint under real-world construction conditions. This research provides both theoretical guidance and practical validation for the design of sustainable, durable, and highly visible road marking materials, contributing to the advancement of environmentally responsible transportation infrastructure. Full article

Soil organic carbon (SOC) restoration in degraded drylands is increasingly promoted for climate mitigation and hydrological co-benefits, yet the scale at which these benefits remain detectable remains uncertain. We therefore evaluate SOC recovery and its hydrological effects across three scales—local, basin, and Earth-system—for a 220,966 ha rangeland restoration pilot in Öndörshireet soum, Central Mongolia, using a cold-calibrated RothC model, Monte Carlo uncertainty propagation, machine-learning-assisted measurement support, and basin-scale mass-balance accounting. Baseline SOC averaged 28.27 tC ha⁻¹, and 20-year RothC simulations projected SOC gains of 0.9–6.4 tC ha⁻¹ across rotational, fenced, and seeded–fenced strata. Monte Carlo emission-reduction rates were 0.33–2.19 tCO₂e ha⁻¹ yr⁻¹, and the conservative VM0042 deduction chain yielded approximately 10,900–12,200 verified carbon units per year. At the local scale, translating SOC gains into plant-available water capacity produced a small but positive hydrological response—reduced flash runoff, lower flood exceedance and storm runoff, higher baseflow contribution, and lower streamflow flashiness—expressed through flow stabilization rather than increased annual water volume. Across the three scales evaluated here, SOC recovery yields a small increase in plant-available water capacity (≈0.09 mm) locally, associated with reduced flash runoff and greater flow stability; at the basin scale, the signal is three to four orders of magnitude below interannual discharge variability; and at the Earth-system scale, no measurable freshwater or global cooling effect is supported. National-scale estimates indicate substantial credible mitigation potential but negligible Arctic freshwater impacts. By separating local mechanisms from basin- and Earth-system detectability, this framework distinguishes credible local co-benefits from Earth-system over-attribution in dryland carbon projects. Full article