Low Emission Rates Research Articles

Comparing space-based to reported carbon monoxide emission estimates for Europe's iron and steel plants

Abstract. We use satellite observations of carbon monoxide (CO) to estimate CO emissions from European integrated iron and steel plants, the continent's highest-emitting CO point sources. We perform analytical inversions to estimate emissions from 21 individual plants using observations from the TROPOspheric Monitoring Instrument (TROPOMI) for 2019. As prior emissions, we use values reported by the facilities to the European Pollutant Release and Transfer Register (E-PRTR). These reported emissions vary in estimation methodology, including both measurements and calculations. With the Weather Research and Forecasting (WRF) model, we perform an ensemble of simulations with different transport settings to best replicate the observed emission plumes for each day and site. Comparing the inversion-based emission estimates to the E-PRTR reports, nine of the plants agree within uncertainties. For the remaining plants, we generally find lower emission rates than reported. Our posterior emission estimates are well constrained by the satellite observations (90 % of the plants have averaging kernel sensitivities above 0.7) except for a few low-emitting or coastal sites. We find agreement between our inversion results and emissions we estimate using the cross-sectional flux (CSF) method for the seven most strongly emitting plants, building further confidence in the inversion estimates. Finally, for four plants with large year-to-year variability in reported emission rates or large differences between the reported emission rate and our posterior estimate, we extend our analysis to 2020. We find no evidence in either the observed carbon monoxide concentrations or our inversion results for strong changes in emission rates. This demonstrates how satellites can be used to identify potential uncertainties in reported emissions.

Effects of Forest Land Mulching on the Soil CO2 Emission Rate of Phyllostachys violascens Forests

This study investigates the dynamics of soil CO2 emissions during the cover period of Phyllostachys violascens and the impact of different cover measures, aiming to provide references for reducing the environmental effects of bamboo cover. An L27 (913) orthogonal experimental design was employed, setting the following variables: (1) heating materials: chicken manure, straw cake, and wheat ash; (2) thickness of husk layer: 15 cm, 25 cm, and 35 cm; (3) soil moisture levels before covering: moisture to 10 cm, 15 cm, and 20 cm. The soil CO2 emission rate showed a unimodal curve, with a significant overall increase during the cover period. Throughout the entire cover period, the average soil CO2 emission rate (25.39 μmol·m−2·s−1) was 5.1 times higher than that of the uncovered Lei bamboo forest (5.02 μmol·m−2·s−1) during the same period. Thicker husk layers (25 cm and 35 cm) corresponded to higher soil CO2 emission rates, with significant differences noted among the thicknesses. When the soil was moist to 10 cm, the CO2 emission rate was highest (62.51 μmol·m−2·s−1); moisture to 15 cm and 20 cm resulted in significantly lower emission rates. Chicken manure produced the highest peak CO2 emissions in the third week, at 70.64 μmol·m−2·s−1, while straw cake and wheat ash reached their peaks in the fifth week, at 66.56 μmol·m−2·s−1 and 57.58 μmol·m−2·s−1, respectively. The interactions between the three factors (heating materials, husk layer thickness, and moisture levels) significantly affected the soil CO2 emission rates. By optimally configuring these factors, CO2 emissions can be regulated. This study recommends using wheat ash or straw cake as heating materials, combined with a 25 cm husk layer thickness, and moistening the soil to 15 cm before covering. This approach effectively reduces the peak and total soil CO2 emissions while ensuring suitable soil temperatures for the growth of bamboo shoots in spring. This research provides a scientific basis for the environmental management of bamboo forests, aiding in the optimization of covering measures to achieve low-carbon and sustainable bamboo management.

Preclinical Evaluation of an Al18F-Radiolabeled Bicyclic Peptide Targeting Nectin-4.

Precisely assessing nectin-4 expression in tumors is important in identifying patients who may benefit from nectin-4-targeted therapies. In our previous work, we developed a bicyclic peptide-based nectin-4-targeting radiotracer 68Ga-N188 and validated its nectin-4 detection efficacy. However, the relatively short half-life and low positron emission rate of 68Ga limit its further application. In this study, we constructed three novel nectin-4-targeting ligands N230-232 based on a bicyclic peptide structure and labeled with radionuclide 18F, which has a longer half-life and a higher positron emission rate, for PET imaging. Micro-PET/CT imaging-based screening showed that Al18F-N231 had the best imaging contrast with a tumor-to-muscle ratio of 10.97 ± 2.39. Further characterization demonstrated that ligand N231 had a high affinity to nectin-4 with a Kd of 4.29 nM, and Al18F-N231 had a good stability and safety profile in vivo. Biodistribution studies validated the specific binding of Al18F-N231 to nectin-4 in vivo, with tumor uptake in the nectin-4+ SW780 tumor group being 1.45- and 3.75-fold higher than that in the nectin-4- 5637 tumor group and blocking group, respectively. Based on the results of this work, Al18F-N231 has promising capability for noninvasive nectin-4 detection in vivo.

Fluorotelomer Alcohol (FTOH) Emission Rates from New and Old Rain Jackets to Air Determined by Iodide High-Resolution Chemical Ionization Mass Spectrometry

Per- and polyfluoroalkyl substances (PFAS), which include fluorotelomer alcohols (FTOHs), are synthetic chemicals used in consumer products because of their water-, stain-, and grease-repellent properties; thus, PFAS are commonly found in functional clothing such as rain jackets. To date, emissions of PFAS from products to indoor air have not been well characterized, although many PFAS-containing products are used and stored indoors. We used a test chamber connected to a high-resolution time-of-flight chemical ionization mass spectrometer equipped with iodide as a reagent ion (I-HR-ToF-CIMS) to measure emission rates for four FTOHs from 10 rain jackets and one backpack cover. The materials were categorized as old/used, new, or “PFAS-free”, and they were tested under two different scenarios, i.e., immediately out of package and after airing out. We observed real-time FTOH emissions from all materials. Under the out-of-package scenario, emissions of 6:2, 8:2 and 10:2 FTOH showed characteristics that indicate mass transfer is limited by internal diffusion, with a high initial peak followed by a lower steady-state emission rate. Peak emission rates correlated well with material-phase concentrations determined by an offline extractive gas chromatography-mass spectrometry (GC-MS) method. Our results further suggest that the old, used jackets had, on average, higher peak emission rates and higher material-phase concentrations than the new jackets, largely driven by 8:2 FTOH. “PFAS-free” materials had the overall lowest emission rates and material-phase concentrations. After airing out, emission rates were on average an order of magnitude lower than peak emission rates. Our findings emphasize the importance of considering consumer products like rain jackets as sources of indoor exposure to PFAS.

Production Simulation of Stimulated Reservoir Volume in Gas Hydrate Formation with Three-Dimensional Embedded Discrete Fracture Model

Natural gas hydrates (NGHs) in the Shenhu area of the South China Sea are deposited in low-permeability clayey silt sediments. As a renewable energy source with such a low carbon emission, the exploitation and recovery rate of NGH make it difficult to meet industrial requirements using existing development strategies. Research into an economically rewarding method of gas hydrate development is important for sustainable energy development. Hydraulic fracturing is an effective stimulation technique to improve the fluid conductivity. In this paper, an efficient three-dimensional embedded discrete fracture model is developed to investigate the production simulation of hydraulically fractured gas hydrate reservoirs considering the stimulated reservoir volume (SRV). The proposed model is applied to a hydraulically fractured production evaluation of vertical wells, horizontal wells, and complex structural wells. To verify the feasibility of the method, three test cases are established for different well types as well as different fractures. The effects of fracture position, fracture conductivity, fracture half-length, and stimulated reservoir volume size on gas production are presented. The results show that the production enhancement in multi-stage fractured horizontal wells is obvious compared to that of vertical wells, while spiral multilateral wells are less sensitive to fractures due to the distribution of wellbore branches and perforation points. Appropriate stimulated reservoir volume size can obtain high gas production and production efficiency.

Optimizing kitchen ventilation with an integrated stove air supply-exhaust system for reducing PM2.5 intake fraction and enhancing energy efficiency

Ensuring good ventilation is crucial for reducing the pollution caused by cooking activities in the indoor environment. Among them, fume exhaust devices as a vital component of kitchen ventilation, and their performance is particularly critical. Merely increasing the air volume of exhaust devices to remove fumes not only leads to the higher energy consumption of exhaust fans, but also has limited practical effect on reducing pollution. For improving the ventilation condition and reducing the energy consumption of supply and exhaust fan, a new ventilation system for kitchen with integrated stove air supply-exhaust (ISASE) was developed in this study. Firstly, the orthogonal experiment was utilized for arranging different combination schemes of five influencing factors, including the emission rate, exhaust flow, upper air supply angle, upper and lower air supply velocities. Then, the effect of ISASE in reducing the intake fraction of PM2.5 under each scheme was studied by using the computational fluid dynamics method. The energy consumption of this system under different ventilation schemes was investigated with on-site testing. Finally, performance-gaining rate was proposed by introducing intake fraction reduction rate and energy consumption growth rate to quantitatively evaluate the performance advantage of ISASE. Polynomial fitting was also used to explore the energy-saving effect of ISASE at high emission rate. The results showed that at low, medium, and high emission rates, the intake fraction of PM2.5 was reduced by 65.0 %–84.2 %. However, the energy consumption of ISASE merely increased by 7.4 %–16.8 % compared with traditional integrated stove without air supply conditions. Its maximum performance-gaining rate reached 0.49–0.66. The energy-saving rate of ISASE was 46.7 % compared with traditional integrated stove without air supply when the same intake fraction was achieved at high emission rate. The practical schemes of ISASE at different emission rates were given in this study, which optimized the working performance of integrated stove and provided a useful reference for its innovative design.

Human health impacts and indoor chemical reactions of VOCs from cleaning products and occupants

Occupants and indoor activities are sources of volatile organic compounds (VOCs). We propose a framework to simulate the pollutant pathway using the INCA-Indoor© model and VOC emission rates to derive dynamic concentrations, and the USEtox model to evaluate health impacts in DALYs (Disability-Adjusted Life Years). The applicability of the framework is tested on a case study, and the effect of indoor chemical reactions on health impacts is assessed. In this case study, health impacts were of 0.3 μDALY/day without and 0.4 μDALY/day (13 s/day) with indoor air chemistry (+28 %) out of which 12 % were linked to occupant breath and skin emissions. Cleaning activities led to the highest impacts without chemical reactions (terpinolene, responsible for 0.14 μDALY/day), but indoor air chemistry led to high impacts linked to formaldehyde formation (0.18 μDALY/day). These reactions led to the formation of more formaldehyde, hence leading to 20% more impacts, in summer than in winter. Occupants’ contribution to CO2 concentrations exceeded recommended limits under the given occupancy and ventilation scenario. Secondary organic aerosol (SOA) formation affected indoor particulate matter mass concentrations by up to a factor 1.2 and their number concentrations by up to a factor 25,000 in the presence of VOC emissions. Results of this study indicate that chemical reactions and SOA formation are important factors to consider in indoor air quality impact assessment. A larger number of activities and scenarios can be tested to improve the robustness of the conclusions, since, under different scenarios (for e.g. activities with lower emission rates) and with more complete toxicity data, these conclusions are likely to change.

Multi-objective optimisation of hybrid renewable energy systems for Colombian non-interconnected zones

Colombia’s Atlantic coast wind and solar resources could enhance energy mix and self-generation. Renewable clean energy has been studied in response to fossil fuel pollution. Wind and solar photovoltaic systems have low initial, operational, and levelized energy costs. Variable wind and sun radiation may limit availability. In this regard, hybrid renewable energy systems (HRES) and energy storage have become crucial. These systems can effectively meet load demand by utilising complementary renewable resources. This study deals with sizing a wind and photovoltaic HRES with storage, using a Particle Swarm Optimisation algorithm for yearly variable resources in a non-interconnected zone in La Guajira, Colombia. The study evaluates the LCOE, probability of load loss, and the system’s CO2 emission. It develops a sensitivity analysis to determine the importance of each objective factor. From a life cycle analysis, an HRES configuration with low LCOE and environmental emission rates is associated with the size of the wind resource; the HRES configuration with minimum LCOE values is close to obtaining higher equivalent CO2e emissions. The study highlights the configuration obtained for the Colombian context, giving more importance to the environmental factor and reaching an LCOE of 0.754 USD/kWh and emission of 18.97 tCO2e/year; this configuration also increases the wind energy generation, reaching 41 % more share, compared to the configuration obtained when the economic factor is a priority.

Mechanism underlying revetment effects on the spatial distribution of nitrogen removal and N2O emissions in riparian zones at summer

Study Region, Shanghai, China, Study FocusUrban riparian zones can mitigate or even control nitrogen pollution in rivers through nitrification and denitrification processes. However, these processes also produce N2O, a potent greenhouse gas. During urbanization, various types of revetments have been constructed in riparian zones. These revetments alter the exchange of materials and energy between the riparian zone and the river, which in turn affects the nitrification and denitrification processes in the riparian zone. However, the mechanisms by which revetments impact nitrogen removal and N2O emissions in riparian zones are not yet clear, and the ways in which revetments balance nitrogen removal and N2O emissions remain unknown. Therefore, in a single river section, natural (NR), permeable (PR), and impervious revetment (IR) types were replicated. Measurements are taken of nitrogen removal, N2O emissions, and related environmental indicators in both the river-riparian interface (RRI) and the riparian zone area outside the RRI (RZ). The study analyzes the differences in environmental factors, nitrification and denitrification potentials, and N2O emission rates among the different revetments to identify the main factors affecting nitrogen removal and N2O emissions in the riparian zone. It also explores the potential mechanisms by which revetments influence the spatial distribution of nitrogen removal and N2O emissions in the summer riparian zone.New Hydrological Insights for the Region: PR exhibit greater denitrification potential and lower N2O emission rates. The denitrification potential is higher in the RRI compared to RZ, while the N2O emission rate is lower than in RZ. nirK is the primary factor influencing denitrification potential, whereas nosZII predominantly affects N2O emissions. The lower soil carbon-to-nitrogen ratio in PR increases the abundance of nirK, thereby enhancing the riparian zone's denitrification potential. Moreover, greater aboveground vegetation biomass increases the abundance of nosZII, reducing the N2O emission rate. The study results could provide guidance for urban ecological restoration and greenhouse gas emission reduction.

Low nitrous oxide fluxes from mineral affected peatland soils in Iceland

Nitrous oxide (N2O) is a potent greenhouse gas, and soil is one of its most substantial sources. Emissions are influenced by both biotic and abiotic processes, as well as the physiochemical properties of the medium. Organic soils fully drained in boreal climates are a potentially significant source of nitrous oxide. Lower, drainage levels and nutrient availability have been shown to reduce N2O emissions. Predicting N2O emissions from agriculturally managed peatlands is challenging. In situ measurements are crucial for addressing these difficulties. This study presents three years of in situ field measurements of nitrous oxide fluxes and soil hydrological status in peatland soils under different agricultural management regimes: cultivated drained (CD), uncultivated drained (UCD), and wet (W) in Western Iceland. Fluxes were quantified by analysing a time-concentration series obtained from permanent chambers and subsequently evaluated using gas chromatography in the laboratory. The minimum potential N2O consumption rate (mean ± 95 % Cl) was estimated as 0.76 ± 0.38, 0.56 ± 0.18 and 0.56 ± 0.14 mg N2O-N m⁻² day⁻¹ for CD, UCD, and W sites, respectively. Yearly accumulated emissions were estimated as 2.24 ± 1.47, 1.26 ± 0.64 and 0.26 ± 0.44 kg N2O-N ha−1 yr−1 for CD, UCD, and W sites, respectively. The relatively low emission rates observed at drained sites can be explained by the stable water content, and by limited availability of soil phosphorus, which hampers N2O production and potentially leads to more active N2O consumption. Both the stable water content and low phosphorus availability is explained by mineral inputs to the peatlands, acting through decreased soil unsaturated hydraulic conductivity and increased phosphorus retention. The effects of mineral content offer potential mitigation option to decrease N2O emissions. This study highlights the complexity of N2O emissions from peatland soils and emphasizes the significance of site-specific factors in managing greenhouse gas emissions. Further studies investigating the underlying processes behind N2O fluxes in the peatland and andic soils are recommended.

Tracing the odor source of crumb rubber modified asphalt emissions and evaluating the deodorization effect of attapulgite

Crumb rubber modified asphalt (CRMA) is widely used in road construction due to its excellent performance. However, it generates significant odorous gases during paving. To analyze the odor contribution, both untreated crumb rubber and desulfurized rubber were involved in this study to prepare CRMA and desulfurized rubber modified asphalt (DRMA). Attapulgite was selected as an emission reduction agent to reduce the odorous emissions released from CRMA and DRMA. An indoor fume collection system and gas chromatography-mass spectrometry (GC-MS) analysis were used to trace the odor source and quantify the odorous emissions. A comprehensive olfactory thresholds database for CRMA emissions was further established to evaluate the odor level of various rubberized asphalt binders by using three-point comparative odor bag method, along with known olfactory thresholds of certain compounds reported in the literature. Dynamic shear rheometer (DSR), multiple stress creep recovery (MSCR), bending beam rheometer (BBR) and Brookfield viscosity tests were used to analyze the effect of attapulgite on rheological properties of CRMA and DRMA. Results indicated that odor emission rate of CRMA containing 1 %, 3 %, and 5 % attapulgite was decreased by 42.62 %, 63.29 %, and 71.06 %, respectively. Benzothiazole, derived from tire rubber vulcanization accelerator, can be reduced by 60.25 % with 1 % attapulgite, demonstrating excellent performance in terms of reducing target odor emissions. Although DRMA has a lower emission rate than that of conventional CRMA, the addition of 1 % attapulgite can further reduce the odor emission rate of DRMA by 37.92 %. The addition of attapulgite has less impact on the overall performance of CRMA and DRMA. Besides, it was found that attapulgite can reduce the viscosity of rubberized asphalt binders, which is beneficial for rubberized asphalt mixture paving and compaction. Considering odor reduction, performance, and economic factors, the optimal attapulgite content was determined to be 5 % for CRMA and 1 % for DRMA. This approach successfully reduces odorous emissions while maintaining the desirable properties of CRMA, making it a viable solution for environmentally friendly road construction.

Optimization of engine performance, emission and combustion parameters by using mixed nonedible oil biodiesel with nano-additives using hybrid techniques

The current study is focused on three nonedible oils resource such as Ceiba pentandra, Mahua longifolia, and Azadirachta indica mixed together in a specific proportion for biodiesel production. The produced biodiesel serves as an alternative fuel source for operating a variable compression ratio diesel engine, addressing escalating environmental pollution and stringent emission standards. A nano-additive comprising CaO–TiO2 is incorporated into biodiesel blends to enhance engine performance and mitigate emissions. The matrix undergoes experimentation and validation using Box-Behnken Design, Deep Belief Network, and a hybrid DBN-based Arithmetic Optimization Algorithm to optimize engine parameters for achieving higher brake thermal efficiency, lower emission rates, and reduced brake-specific fuel consumption. All the experiments are conducted by varying the engine load, speed, quantity of nano-additives and biodiesel blend. The final empirical model is more significant for DBN with a regression coefficient greater than 0.99. The converged optimized input parametric ranges are load 60 %, biodiesel 25 %, nano-additive 20 wt% and engine speed 1400 rpm. When comparing diesel fuel with CaO–TiO2 biodiesel, the proposed method resulted in significant improvements, including a 41 % reduction in brake-specific fuel consumption, a 32 % decrease in CO emissions, a 25 % decrease in NOX emissions, and a 16.9 % increase in brake thermal efficiency.

Effect of alternative biogas-methane fuels use on performance and emissions in turbojet engine

Researchers are trying to find alternative fuels to traditional fuels as traditional fuels are running out. This study is to predict turbojet gas turbine emission and performance using Methane and Biogas fuel blend for turbojet in Gasturb-14 program. Based on the physicochemical properties of each fuel, parameters were calculated for methane supplemented B1, B2 and B3 and pure methane fuel compositions. The heat of combustion for each blend was then obtained using GasTurb Details6 and the design points of the turbojet engine were determined. The program was run using biogas fuels to analyze performance and emission characteristics such as carbon monoxide, carbon dioxide, etc. In this study, the B3 blend was found to be the most effective Specific Fuel Consumption value with 32.22 g/kNs. It also produced lower emission rates for CO and CO2 compared to B1 and B2 fuels. The first finding is that it is possible to burn an alternative biogas fuel to methane fuel. The results also show that biogas is very similar to methane in terms of temperature distributions in the combustion chamber due to its high methane content compared to other biogases.

A Continuous Plug-Flow Anaerobic-Multistage Anoxic/Aerobic Process Treating Low-C/N Domestic Sewage: Nutrient Removal, Greenhouse Gas Emissions, and Microbial Community Analysis

The anaerobic-multistage anoxic/aerobic (A-MAO) process has shown good potential for advanced nitrogen removal in recent years, but its greenhouse gas emissions still need to be fully explored. The effects of the influent distribution and external carbon source sodium acetate on nutrient removal, greenhouse gas emissions, and the microbial community structure in a continuous plug-flow A-MAO reactor fed with real low C/N ratio domestic sewage were investigated. The results showed that altering the allocation of carbon source resulted in average chemical oxygen demand (COD) and total nitrogen (TN) concentration in effluent reduced to 26.10 ± 4.86 and 6.65 ± 1.73 mg/L, respectively. Both operations reduced the emission rate of greenhouse gas. While the addition of external car-bon sources leaded to lower N2O emission rates and higher CO2 and CH4 emission rates. The addition of sodium acetate facilitated nitrification and denitrification processes, thereby leading to a reduction in N2O production. Meanwhile, it spurred the growth of methanogenic bacteria and heterotrophic microorganisms, thus boosting the production of CO2 and CH4. Influent distribution promoted the increase of Bacteroidota, Chloroflexi and Acidobacteriota of the reactor. The enrichment of typical hydrolytic bacteria and glycogen accumulating organisms (GAOs) increased the utilization efficiency of carbon sources in the system after the addition of sodium acetate. The significant increase of typical denitrifying bacteria (DNBs) Azospira reduced the N2O emission during heterotrophic denitrification process, which was considered to be an important functional genus for increasing nitrogen loss in this system. The rational utilization of carbon source makes the difference in metabolism function. The study provides a valuable strategy for comprehensively evaluating the pollutant removal and greenhouse gas emission reduction from the A-MAO process.

Toward "super-scintillation" with nanomaterials and nanophotonics.

Following the discovery of X-rays, scintillators are commonly used as high-energy radiation sensors in diagnostic medical imaging, high-energy physics, astrophysics, environmental radiation monitoring, and security inspections. Conventional scintillators face intrinsic limitations including a low extraction efficiency of scintillated light and a low emission rate, leading to efficiencies that are less than 10 % for commercial scintillators. Overcoming these limitations will require new materials including scintillating nanomaterials ("nanoscintillators"), as well as new photonic approaches that increase the efficiency of the scintillation process, increase the emission rate of materials, and control the directivity of the scintillated light. In this perspective, we describe emerging nanoscintillating materials and three nanophotonic platforms: (i) plasmonic nanoresonators, (ii) photonic crystals, and (iii) high-Q metasurfaces that could enable high performance scintillators. We further discuss how a combination of nanoscintillators and photonic structures can yield a "super scintillator" enabling ultimate spatio-temporal resolution while enabling a significant boost in the extracted scintillation emission.

Methane Emissions From the Qinghai‐Tibet Plateau Ponds and Lakes: Roles of Ice Thaw and Vegetation Zone

AbstractComprehensive seasonal observation is essential for accurately quantifying methane (CH4) emissions from ponds and lakes in permafrost regions. Although CH4 emissions during ice thaw are important and highly variable in high‐latitude freshwater ponds and lakes (north of ∼50°N), their contribution is seldom included in estimates of aquatic‐atmospheric CH4 exchange across different alpine ecosystems. Here, we characterized annual CH4 emissions, including emissions during ice thaw, from ponds and lakes across four alpine vegetation zones in the Qinghai‐Tibet Plateau (QTP) permafrost region. We observed significant spatial variability in annual CH4 emission rates (8.44−421.05 mmol m−2 yr−1), CH4 emission rates during ice thaw (0.26−144.39 mmol m−2 yr−1), and the contribution of CH4 emissions during ice thaw to annual emissions (3−33%) across different vegetation zones. Dissolved oxygen concentration under ice, along with substrate availability and water salinity, played critical roles in influencing CH4 flux during ice thaw. We estimated annual CH4 emissions from ponds and lakes in the QTP permafrost region as 0.04 (0.03−0.05) Tg CH4 yr−1 (median (first quartile−third quartile)), with approximately 20% occurring during ice thaw. Notably, the average areal CH4 emission rate from ponds and lakes in the QTP permafrost region amounts to only 8% of that from high‐latitude waterbodies, primarily due to the dominance of large saline lakes with lower CH4 emission rates in the alpine permafrost region. Our findings emphasize the significance of incorporating comprehensive seasonal observation of CH4 emissions across different vegetation zones in better predicting CH4 emissions from alpine ponds and lakes.

Performance of local supply-exhaust ventilation around stove with numerical simulation in a residential kitchen

A large number of fine particulate matters (PM2.5) are generated during cooking, which have negative impacts on kitchen environment. This study proposed a novel ventilation strategy of local supply-exhaust ventilation around stove (LSEVAS) for improving air quality in a residential kitchen during cooking. Five factors affecting the performance of LSEVAS were explored with orthogonal design and computational fluid dynamics (CFD). Evaluation indexes including PM2.5 mass concentration in breathing zone (CB), capture efficiency (CE) of fume exhaust device and intake fraction (IF) of occupant were also analyzed. The performance of LSEVAS was also identified without air supply condition in kitchen in terms of these above evaluation indexes. Results show that the emission rate and exhaust air volume were the most significant factors, followed by the upside air supply angle, upside air supply speed and downside air supply speed. The CB in LSEVAS was reduced by 83%, 60% and 66% than without air supply condition under low, medium and high emission rates, respectively. The CE was improved by 1.8%, 13.9% and 14.5%, respectively. The IF value was decreased by one order of magnitude. Furthermore, with increasing of upside and downside air supply speed, the ability of air supply airflow in preventing the escape of PM2.5 became stronger, while the core concentration distribution of PM2.5 was gradually closer to breathing zone of occupant. It means that the novel local ventilation strategy proposed in this study is effective in improving cooking environment in the residential kitchen.

Impact of Eco-Friendly Plaster Using Epoxy Resin and Epoxy Hardener on Mechanical Properties under Compression and Tension.

BISCO plaster (BRP) is an environmentally friendly material with high mechanical properties and is considered a great elective to conventional materials such as gypsum and cement. Our investigation seeks to examine BISCO plaster (BRP) and a mixture of resin and hardener in three proportions (30%, 45%, and 60%) to achieve our ultimate goal, which is to preserve the environment and achieve the vision of the Kingdom of Saudi Arabia 2030 to reach zero carbon emissions by 2060? Emissions tests were performed, and although the CO2 level was zero, they emitted SO2 sulfur dioxide and NO2 nitrogen dioxide, and 60% was the lowest emission rate. We also used ANSYS 2023 R1 software to compare them with their mechanical properties resulting from tensile and compression testing. In this study, we looked closely at the mechanical characteristics of different materials designed for wall coverings, with particular emphasis on their environmental sustainability. We carried out experiments to gauge the tensile and compressive stress on samples with varying mixing ratios. Our main objective was on crucial mechanical properties such as the modulus of elasticity, ultimate tensile strength, yield strength, yield strain, modulus of resilience, and ductility. Through meticulous scrutiny, we determined that the amalgamation of these mechanical attributes at the 30% mixing ratio provides an optimal combination for attaining structural integrity, adaptability, and resilience in wall coverings. Significantly, this ratio also underscores a commitment to environmentally conscious material selection. Our study offers important new insights into the selection of wall covering materials by providing a detailed understanding of their mechanical behavior under various stress conditions. It aligns with the increasing significance of environmental responsibility in contemporary design and construction. By emphasizing the 30% mixing ratio, our findings establish a foundation for informed decision making, promoting the utilization of sustainable materials that achieve a balance between strength, flexibility, and longevity. This ensures optimal performance in practical applications while simultaneously minimizing the environmental impact.

The Role of Emission Size Distribution on the Efficacy of New Technologies to Reduce Methane Emissions from the Oil and Gas Sector.

Methane emissions from oil and gas operations exhibit skewed distributions. New technologies such as aerial-based leak detection surveys promise cost-effective detection of large emitters (greater than 10 kg/h). Recent policies such as the US Environmental Protection Agency (EPA) methane rule that allow the use of new technologies as part of leak detection and repair (LDAR) programs require a demonstration of equivalence with existing optical gas imaging (OGI) based LDAR programs. In this work, we illustrate the impact of emission size distribution on the equivalency condition between the OGI and site-wide survey technologies. Emission size distributions compiled from aerial measurements include significantly more emitters between 1 and 10 kg/h and lower average emission rates for large emitters compared to the emission distribution in the EPA rule. As a result, we find that equivalence may be achieved at lower site-wide survey frequencies when using technologies with detection thresholds below 10 kg/h, compared to the EPA rule. However, equivalence cannot be achieved with a detection threshold of 30 kg/h at any survey frequency, because most emitters across most US basins exhibit emission rates below 30 kg/h. We find that equivalence is a complex tradeoff among technology choice, design of LDAR programs, and survey frequency that can have more than one unique solution set.

The relationship between carbon intensity of loans and renewable energy production: A cross-country analysis of developmental stage and financial system maturity effects

This study explores the influence of carbon intensity of loans issued by financial institutions (CIL) on facilitating energy transition. By analyzing cross-country panel data from 2005 to 2018, we unveil a notable influence of CIL on renewable energy production, taking into account cross-sectional dependence. Our regression analysis, employing panel-corrected standard errors, indicates that a 1% decrease in CIL correlates with a 0.9169% and 0.9189% rise in renewable energy production per capita and per GDP, respectively, along with a 0.1180% growth in renewable energy's share. This effect of promotion is more pronounced in nations with higher developmental levels, lower emission rates, greater banking sector reliance, and increased energy import dependency. Additionally, our study identifies a significant role played by the development of financial institutions in the reduction of CIL. Conversely, the moderating influence of R&D appears less clear. Utilizing the Panel Granger test, we establish a bidirectional causal link between CIL and renewable energy production, which sustains over the long term. Our findings offer valuable insights for policymakers and financial bodies aiming to meet climate objectives.