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Social scientists should be more deliberate in how they define and measure government efforts to reduce greenhouse gas emissions. The authors highlight key distinctions among three dimensions of climate policy: the commitments made by governments, the actions that governments take, and the outcomes they produce. In turn, the authors detail the challenges of measuring these dimensions, and discuss the tradeoffs of alternative measurement strategies, including how well they meet the accepted standards for measurement validity. The authors also identify promising avenues for further research.

INTRODUCTION: The environmental impact of holding in-person academic conferences and continuing medical education (CME) programs can be significant. In-person conferences provide a unique social and professional platform to engage in networking and foster professional development; however, there is an opportunity for hybrid and virtual platforms to provide CME for broader audiences looking to improve their clinical skills and strengthen their knowledge base. This study seeks to describe the reduction in carbon emissions associated with a webinar hosted by an online dermatology-focused medical education platform. METHODS: This cross-sectional study used the location of deidentified virtual attendees of a webinar to predict the carbon emissions produced if attendees had instead traveled to the location of the most recent Integrative Dermatology Symposium (Sacramento, CA). Following collection of each virtual attendees location, the mode of transportation was predicted on the basis of each participants distance to the conference. RESULTS: The estimated carbon emissions were calculated for 576 participants. The total estimated, unadjusted carbon emissions for both attendees predicted to fly or drive was 370,100 kg CO2. The emissions produced per participant from those expected to fly to an in-person CME after adjusting for all additional passengers on every flight were 4.5 kg CO2. The emissions produced per participant from those expected to drive were 42.7 kg CO2. CONCLUSION: The use of a virtual CME webinar led to a significant reduction in travel-related carbon dioxide emissions when compared to running the same program in-person event. When accounting for all passengers traveling via plane on any flight, driving to an event produced more emissions per participant than flying.

Background NOAA’s Hazard Mapping System (HMS) smoke product comprises smoke plumes digitised from satellite imagery. Recent studies have used HMS as a proxy for surface smoke presence. Aims We compare HMS with airport observations, air quality station measurements and model estimates of near-surface smoke. Methods We quantify the agreement in numbers of smoke days and trends, regional discrepancies in levels of near-surface smoke fine particulate matter (PM2.5) within HMS polygons, and separation of total PM2.5 on smoke and non-smoke days across the contiguous US and Alaska from 2010 to 2021. Key results We find large overestimates in HMS-derived smoke days and trends if we include light smoke plumes in the HMS smoke day definition. Outside the western US and Alaska, near-surface smoke PM2.5 within areas of HMS smoke plumes is low and almost indistinguishable across density categories, likely indicating frequent smoke aloft. Conclusions Compared with airport, Environmental Protection Agency (EPA) and model-derived estimates, HMS most closely reflects surface smoke in the Pacific and Mountain regions and Alaska when smoke days are defined using only heavy plumes or both medium and heavy plumes. Implications We recommend careful consideration of biases in the HMS smoke product for air quality and public health assessments of fires.

This article presents the first practical engine system using ammonia (NH 3) as a mono-fuel. To address the low flammability and distinctive odor, the system incorporates a four-cylinder spark ignition engine with an onboard reformer applying autothermal reforming to generate hydrogen as a combustion promoter, a three-way catalyst (TWC), and selective catalytic reduction (SCR) catalyst as an NH 3 adsorbent. The system successfully reduced nitrogen-based exhaust emissions during cold starts, which was a challenge, by controlling the air-fuel ratio (λ). Nitrogen oxides were suppressed by rich combustion until the TWC became active, while NH 3 passing through the TWC was adsorbed by the SCR catalyst. After TWC activation, simultaneous purification of NH 3 and nitrogen oxides was achieved by controlling λ at 1. The adsorbed NH 3 was subsequently purified along with nitrogen oxides via the SCR reaction by lean operation, regenerating the adsorption capacity and achieving near-zero emissions. • An NH 3 mono-fueled engine system with a reformer and an adsorbent was proposed. • Successful cold start-up was achieved with suppressed NH 3 , NO x , and N 2 O emissions. • Rich combustion reduced NO x and N 2 O until a three-way catalyst is activated. • Adsorbed NH 3 was purified with NO x by lean operation using SCR reactions. • Production of N 2 O on TWC was reduced avoiding lean and low temperature conditions. [ABSTRACT FROM AUTHOR]

In the Industry 4.0 era, manufacturers commonly adopt digital technologies such as Internet of Things (IoT) and blockchain technology to improve information disclosure. In this paper, we focus on how the government can properly set an extended producer responsibility (EPR) policy (penalty or subsidy) and impose it on the manufacturer to entice the manufacturer to set the optimal pollutant emissions information disclosure (PEID) level which maximizes the social welfare. In the basic model, we build a simple consumer utility based stylized analytical model. We first derive from the government perspective the social welfare function and obtain the closed-form expression of the optimal level of PEID. Then, we explore the manufacturer's problem on PEID under the EPR policy. We show how the EPR policy can be set so that the government can entice the manufacturer to set the PEID level which maximizes the social welfare. We also uncover the factors governing the EPR policy, and show the situations under which the EPR policy is in fact a subsidy scheme (i.e., the government sponsors the manufacturer). To derive more insights and check for robustness, we extend the basic model in a number of ways, namely (i) the situation when the manufacturer is risk sensitive, (ii) the case with the extended consumer responsibility (ECR) policy, (iii) the scenario when there is a per unit PEID level dependent operating cost (i.e., a variable cost), and (iv) the case when the platform is not supported by blockchain. We find that the form of EPR policy and the qualitative insights remain valid for the cases when the manufacturer is risk sensitive and there is a PEID level dependent operating cost. Interestingly, we uncover that, unlike the EPR policy, the use of ECR policy fails to help. [ABSTRACT FROM AUTHOR]

The grate-kiln process for iron-ore pellet induration utilizes pulverized coal fired burners. In a developed infrastructure for H 2 , it might be desirable to heat the existing rotary kilns with renewably produced H 2. Technical challenges of H 2 heating of grate-kilns include high emissions of NO X and maintaining sufficient heat transfer to the pellet bed. This article examined cofiring (70% coal/30% H 2) in 130 kW experiments using two different integrated burner concepts. Compared to pure coal combustion, cofiring creates a more intense, smaller flame with earlier ignition and less fluctuations. The process temperature and heat transfer are enhanced in the beginning of the kiln. The co-fired flames emit 32% and 78% less NO X emissions compared to pure coal and H 2 combustion, respectively. We can affect the combustion behavior and NO X emissions by the burner design. H 2 /coal cofiring using integrated burners is probably an attractive solution for emission minimization in rotary kilns. [Display omitted] • Pure H 2 combustion faces obstacles replacing coal in current induration kilns. • Coal and H 2 cofiring is investigated as an alternative. • Cofiring enhances the ignition of coal particles and stabilizes the flame. • Cofiring emits less NO X emissions compared to traditional pure coal and pure H 2. • Cofiring and pure H 2 flames offer elevated heat transfer close to the burner. [ABSTRACT FROM AUTHOR]

Buckwheat husks are a valuable source of carbon and show the potential to be used as an energy source. However, due to low bulk density and low susceptibility to compaction, it is beneficial to use them in the form of co-pellets. The study presents comprehensive research detailing buckwheat husks' potential for co-pelletization with oily (peanut husks) and dusty (senna leaves) agri-food wastes, whereas the effect of material parameters such as the amount of additive (10, 15, 20%) and the process parameters as the die rotational speed (170, 220, 270 rpm) on pellets' quality (kinetic durability, bulk and particle density, degree of compaction) and the energy consumption of the pelletization process were examined. Ten percent of potato pulp as a binder was added to each pelletized mixture. It was found that an increase in the senna leaf content affects positively the kinetic durability of pellets. The fatty peanut husks have a negative effect on the pellets' quality (measured by the kinetic durability and bulk density); however, both additions of senna leaves and peanut husks are lowering the energy consumption of the pelletizer. The highest quality pellets and the addition of 10% peanut husks to buckwheat husks (kinetic durability of 96%) and 20% of senna leaves to buckwheat husks (kinetic durability of 92%) obtained at 170 rpm were subjected to combustion in a fixed-bed unit, and the content of CO, CO2, NO, SO2, HCl, and O2 in the fuel gases was measured. The emission factors were higher than the Ecodesign limitations (CO > 500 mg·Nm−3, NO > 200 mg·Nm−3). The obtained results indicate that buckwheat husks can be successfully co-pelletized with other waste biomass; however, the pellets to be combusted require a boiler with improved air-supplying construction. [ABSTRACT FROM AUTHOR]

The optimization of Venturi mixers in burners is critical for enhancing combustion efficiency and minimizing emissions. In this study, we utilize the adjoint method to analyze and refine the design of a Venturi mixer. Our numerical simulations integrate the species transport equation with the eddy dissipation model (EDM) for reacting flow and the generalized k- (GEKO) model to simulate turbulence. By solving adjoint equations, we effectively compute the shape sensitivity for various observables, including pressure drop, outlet fuel variance/uniformity deviation index, air and fuel mass flow rates, and outlet CO mass fraction. The shape sensitivity analysis uncovers the interplay between the observables and the appropriate weights for multiple objective optimizations. Subsequently, we perform gradient-based optimizations to enhance the mixer's performance, employing both shape sensitivity and mesh morphing techniques. We conduct a series of case studies focusing on both cold and reacting flows. The optimization of cold flow provides an in-depth exploration of various optimization strategies, encompassing single-objective and multi-objective optimization with diverse weight combinations. Following this, the optimization under reacting flow conditions improves the fuel/air mixing, leading to the increase of combustion efficiency and hence the reduction of CO emissions. Our findings showcase the potential of an adjoint-based optimization framework in designing Venturi mixers that are efficient and emit lower levels of pollutants. [ABSTRACT FROM AUTHOR]

Climate change and CO2 emissions are critical challenges for the environment and humanity. There is extensive literature on greenhouse gas (GHG) emissions, in particular CO2 emissions. However, comprehensive analyses focusing on electric vehicles (EVs) and their impact are lacking. This study fills this gap by conducting a bibliometric analysis of 1143 peer-reviewed studies from 1989 to 2023. We aimed to identify influential contributions, understand the field's structure, and reveal research gaps. Analysis included citation networks, research impact, authorship patterns, content, and publication trends. We utilized bibliometric techniques to identify the most dominant countries, institutions, authors, journals, articles, and thematic areas related to EVs and emissions. Additionally, we overviewed publications associated with key search terms. Guided by five research dimensions (EVs, emissions, adoption, policies, and infrastructures), we framed specific research questions. This research provides valuable insights for environmentalists, policymakers, regulators, and academic researchers, facilitating access to crucial data on EVs and emissions. [ABSTRACT FROM AUTHOR]

Simple and low-cost flame curtain ("Kon-Tiki") kilns are currently the preferred biochar technology for smallholder farmers in the tropics. While gas and aerosol emissions have been documented for woody feedstocks (twigs and leaves) with varying moisture contents, there is a lack of data on emissions from other types of feedstocks. This study aims to document the gas and aerosol emissions for common non-woody feedstocks and to compare emissions from finely grained, high-lignin feedstock (coffee husk) with those from coarser, low-lignin feedstocks (maize cobs, grass, sesame stems). Throughout each pyrolysis cycle, all carbon-containing gases and NOx were monitored using hand-held sensitive instruments equipped with internal pumps. Carbon balances were used to establish emission factors in grams per kilogram of biochar. The resulting methane emissions were nearly zero (<5.5 g/kg biochar) for the pyrolysis of three dry (~10% moisture) maize cobs, grass, and a 1:1 mixture of grass and woody twigs. For sesame stems, methane was detected in only two distinct spikes during the pyrolysis cycle. Carbon monoxide (CO) and aerosol (Total Suspended Particles, TSP) emissions were recorded at levels similar to earlier data for dry twigs, while nitrogen oxide (NOx) emissions were negligible. In contrast, the pyrolysis of finely grained coffee husks generated significant methane and aerosol emissions, indicating that technologies other than flame curtain kilns are more suitable for finely grained feedstocks. The emission results from this study suggest that certification of biochar made from dry maize, sesame, and grass biomass using low-tech pyrolysis should be encouraged. Meanwhile, more advanced systems with syngas combustion are needed to sufficiently reduce CO, CH4, and aerosol emissions for the pyrolysis of finely grained biomasses such as rice, coffee, and nut husks. The reported data should aid overarching life-cycle analyses of the integration of biochar practice in climate-smart agriculture and facilitate carbon credit certification for tropical smallholders. [ABSTRACT FROM AUTHOR]

A lack of regulation around greenhouse gas (GHG) emissions has led Australian companies to employ arbitrary targets for measuring GHG emissions reduction, which are not translating to the level of emissions reduction required to meet global targets. Despite the well accepted urgency of climate change action, there is a gap in literature with no studies discussing the effectiveness of the various targets for measuring GHG emissions to meet global emission reduction goal. Using correlation and ordinary least squares (OLS) regression analysis, our study of Australian Stock Exchange listed companies shows that the targets suggested by Task Force on Climate‐related Financial Disclosure (TCFD) are the most closely associated with the required emissions reduction. The findings from this study advocate that organisations adopt TCFD recommendations for achieving optimal reduction of greenhouse gas emissions to meet the global targets. Our findings should inform policymakers and practice to align targets to the TCFD recommendations to meet the global emissions reduction commitments and mitigate the most severe impacts of climate change. [ABSTRACT FROM AUTHOR]

The cookstove requires various materials for different stove components, such as the combustion chamber, stove body, insulation, and other accessories, which have a significant impact on the overall combustion performance of the stove. In the present study, two hybrid draft biomass cookstove (HDBC) models with different combustion chamber materials (stainless steel and ceramic refractory cement) were developed and tested. Both stoves in combination with three different insulation materials (perlite, vermiculite, and ceramic wool) were tested using the modified Water Boiling Test (WBT-4.2.3) and Durability Test protocol to assess emissions, efficiency, and stove durability performance. According to the ISO 19867-3:2018 voluntary performance targets, both stainless steel and ceramic combustion chamber stoves with all three insulations met the targets of Tier 5, Tier 4, Tier 3 & 2 and Tier 5 in CO emission, PM2.5 emission, efficiency, and durability performance, respectively. Although there was no significant difference in CO emission, efficiency, modified combustion efficiency (MCE) and durability performance between the two stoves, the ceramic combustion chamber stove emits more PM2.5 than the stainless-steel combustion chamber stove. The combination of stainless-steel combustion chamber and perlite insulation performs overall better than the other combinations. [ABSTRACT FROM AUTHOR]

In Germany, wood pellets must fulfill high quality standards to be utilized in small-scale furnaces. According to current legislation, i.e., the 1st BImSchV, only ENplus A1–certified pellets may be used. Despite these strict requirements, physical fuel parameters can vary within the permissible range and variation usually increases due to fuel transport and storage. Fluctuations in physical fuel parameters may have a strong influence on combustion, especially in pellet stoves with a low degree of automation regarding fuel control and air supply. During this study, pellet length, moisture content, and the content of fines of spruce wood pellets were varied artificially at three levels for each parameter. All pellets were analyzed according to international standards for solid biofuels. Fuels were combusted in a 6 kW pellet stove and selected assortments in a 15 kW pellet boiler. For the pellet stove, pellet length had a significant influence on gaseous but not on total particulate matter (TPM) emissions. Both, rather short (10.3 mm) and long (17 mm) pellets caused an increase in emissions. In contrast, for the boiler, no significant effect of pellet length on gaseous and TPM emissions was observed. A low moisture content (3 w-%) led to increased CO, organic gaseous carbon (OGC), and TPM emissions in the pellet stove. This could be especially relevant for furnaces with very simple or no heat output control as it is common in most pellet stoves. High content of fines (3 to 10 w-%) led to a significant increase in gaseous emissions (CO up to fivefold, OGC up to tenfold) and TPM emissions (up to 1.4-fold) in the pellet stove most likely due to elevated particle entrainment. Overall, the state-of-the-art pellet stove showed larger sensitivity towards variable pellet qualities compared to the automatically stoked pellet boiler; thus, improvements in fuel design and stove technology are recommended. Overall, this study has provided important insights into the influence of pellet length, fines content, and moisture content on emissions from pellet stoves and pellet boilers, which can help drive future technical development in the areas of fuel flexibility and emission reduction. [ABSTRACT FROM AUTHOR]

This paper presents a novel model for co-modal emission calculation and inventory methodology combining the various modes of public transport. A number of available emission calculation models have been reviewed and the proposed methodology has been derived so as to cover all modes effectively in a homogenised manner. Due to the large number of different vehicle types and engine technologies involved, the current approach focuses on characteristics of each country in order to reflect country specific situation in the best possible way. Two case studies are presented. The first one compares two alternative co-modal routes based on their environmental performance, but also on other parameters such as time, distance and cost. The calculated emission factors are used in the second case study for the development of an emission inventory for the public transport sector in Greece. For this inventory, actual activity data from real life were collected from all transport operators in Greece, instead of using statistical data. The calculated results are compared against top-down approaches which use statistical data; this comparison shows that the proposed bottom-up methodology and final calculated data can serve as a basis and baseline scenario for future emission inventories. [ABSTRACT FROM AUTHOR]

Methanol, as a carbon-neutral resource, exhibits significant potential in the automotive sector. The objectives of this study are to investigate the fuel economy, emission characteristics, and combustion properties of methanol in compression-ignition engines. The research findings indicated that the combustion duration of methanol significantly extended with increasing speed and load. In comparison to diesel, methanol exhibited a relatively lower peak heat release rate under various operating conditions. With an increase in injection pressure or an advancement in injection timing, the brake specific fuel consumption (BSFC) decreased initially and then increased. The optimal injection pressure for methanol was lower than that for diesel, while the optimal injection timing was advanced. As the EGR rate increased, BSFC gradually decreased at each speed. When comparing optimized methanol with diesel, the brake thermal efficiency (BTE) of methanol was 37.54%, slightly lower than that of diesel. Methanol's NOx, soot, and CO emissions were significantly lower than diesel, while methanol and formaldehyde emissions were higher, especially with a methanol emission of 0.83 g/kW.h. Overall, applying pure methanol as fuel in compression-ignition engines can significantly reduce emissions while maintaining the BTE as compared with that of diesel fuel, but the methanol emissions in the exhaust increase significantly. [ABSTRACT FROM AUTHOR]

The concerns for global warming have pushed very harsh regulations on conventional propulsion systems based on the use of fossil fuels. New technologies are being promoted, but their current technological status needs further research and development to become a competitive substitute for the ever-present internal combustion engine. Transition technologies like hybrid-electric platforms are the preferred solution, but their dependence on the internal combustion engine demands continued developing and improving this technology. Advanced combustion modes like dual-mode dual-fuel combustion are attractive solutions with room for improvement. This work evaluates the specifics of the hydrocarbon composition emitted during the operation of a medium-duty dual-mode dual-fuel engine, analyzing the specific requirements of a diesel oxidation catalyst for this application. Also, the modeling approach of this after-treatment component is revised for this type of application, proposing a new approach and evaluating numerically the performance of a conventional diesel oxidation catalyst. The results show that the new modeling approach brings better accuracy when modeling the transient operation of the engine. [ABSTRACT FROM AUTHOR]

Ammonia, as a zero-carbon fuel, has the potential to serve as a medium for the production, transportation, and utilization of clean energy. The scaling up of green ammonia production also necessitates broader utilization channels for ammonia. Applying ammonia as a fuel in engines is an effective way to reduce carbon emissions. This paper employs dual direct injection technology of ammonia and diesel in a novel ammonia-fueled engine to implement various control strategies and investigates their effects on combustion and emission performance. The results indicate that when the ammonia injection timing is advanced from −40°CA ATDC to −60°CA ATDC, the flash boiling of liquid ammonia decreases the indicated thermal efficiency (ITE) below 39% and increases unburned gas emissions. Globally, injecting ammonia during the intake stroke could receive better performance. Split injection strategies of diesel significantly improve the ITE, especially under a higher pilot-injection ratio of 75%. Additionally, increasing the load benefits the ammonia combustion process. Raising the IMEP to 12 bar improves ammonia combustion efficiency to over 95%, with an ITE reaching 49%. [Display omitted] • Lifecycle zero carbon emission is achieved through green ammonia combustion. • Zero-carbon fuel ammonia is directly injected into a heavy-duty engine. • The influence of flashing boiling of ammonia in the cylinder is talked about. • Flexible control strategies are tested for lower unburned emissions and higher ITE. [ABSTRACT FROM AUTHOR]

This study suggests a combustion strategy and introduces a new geometry for the combustor of a micro gas turbine fed by ammonia as fuel. Ammonia is essential for making the energy supply chain more eco-friendly because it is seen as an excellent way to transport green hydrogen and as a renewable, carbon-free fuel. This study has considered different cases with a wide range of overall and primary equivalence ratios to find the optimum geometry regarding lower NO X emission, lower unburned NH 3 , lower unburned H 2 , and temperature distribution. A comprehensive case study of CFD simulation was conducted considering earlier research that showed the NO reduction level in an NH 3 -air swirl burner is dependent on the equivalence ratio of the primary combustion zone. The CFD simulation's boundary conditions were set by running a one-dimensional cycle simulation of the micro gas turbine at various loads. Results indicate that by modifying the geometry to include a staged rich-lean strategy with a primary equivalence ratio of 1.07, the NO mole fraction in the combustor can be reduced to one-third of its original level despite the significantly higher Combustor Inlet Temperature (CIT) compared to previous studies. The study found that the unburnt NH 3 and H 2 levels are low enough in the modified design, which shows the fuel is completely consumed and the overall combustion efficiency is optimized. Also, the analysis of the fluid dynamic behavior of the combustor shows that streamlines are uniform, leading to improved heat transfer and better overall system performance. These findings highlight the staged rich-lean strategy's potential by tuning the combustion stages' equivalence ratio as a promising approach to mitigate NO X emissions in ammonia combustion systems while maintaining high energy efficiency. • Study of ammonia combustion in a 3 kWe MGT's combustor. • Proposing a novel design approach for the combustor. • Higher combustor inlet temperature investigation in smaller combustor. • Implementation of a staged rich-lean combustion strategy to reduce NOx emissions by one-third. • Investigation of various primary ERs and identification of the optimal value at 1.07. [ABSTRACT FROM AUTHOR]

Background Methods Results Conclusion Operating rooms generate 1.8 million tons of waste annually, or 20%‒30% of the total healthcare waste in the United States. Our objective was to perform a life cycle assessment (LCA) for endoscopic sinus surgeries (ESSs) in order to analyze its environmental impact.A comprehensive LCA of ESS was performed considering energy, climate, and water use impacts associated with the materials and processes used. It focuses on the ESS performed at a large tertiary academic hospital and then extends the impacts to consider annual US surgeries. The assessment considers end‐of‐life waste management at both landfills and incinerators.Single‐use instrument production constitutes 89%‒96% of the total impacts throughout the life cycle of an ESS. Waste‐to‐energy incineration is shown to be a preferred end‐of‐life destination, as it recovers much of the input production energy of plastic items, ultimately reducing the input to 36%, although this is done at the expense of higher greenhouse gas emissions. For multi‐use items, decontamination dominates environmental impact (>99% of totals), but consideration of reusable items reduces overall energy consumption and global warming potential (GWP) by 25%‒33%.Single‐use items dominate the total environmental impact of ESS. While multi‐use items require additional decontamination over their lifetimes, results show that their incorporation reduces energy consumption and GWP by 25%‒33%, demonstrating the clear environmental benefit. [ABSTRACT FROM AUTHOR]

The current generation portfolio is obligated to incorporate zero-emissions energy sources, predominantly wind and solar, due to the depletion of fossil fuels and the alarming rate of global warming. In the current scenario, power engineers must devise a compromised solution that not only advocates for the adoption of renewable energy sources (RES) but also efficiently schedules all conventional power generation units to balance the increasing load demand while simultaneously minimizing fuel costs and harmful emissions that are currently addressed by Unit Commitment (UC) and Combined Economic Emission Dispatch (CEED) problem solutions. However, the integration of renewable energy resources (RES) further complicates the UC-CEED problem due to their intermittent nature. Recently, metaheuristic algorithms are acquiring momentum in resolving constrained UC-CEED problems due to their improved global solution ability, adaptability, and derivative-free construction. In this research, a computationally efficient binary hybrid version of crow search algorithm and improvised grey wolf optimization is proposed, namely Crow Search Improved Binary Grey Wolf Optimization Algorithm (CS-BIGWO) by inclusion of nonlinear control parameter, weight-based position updating, and mutation approach. Statistical results on standard mathematical functions prove the supremacy of the proposed algorithm over conventional algorithms. Further, a novel optimization strategy is devised by integrating enhanced lambda iteration with the CS-BIGWO algorithm (CS-BIGWO- λ ) to solve a day-ahead UC-CEED problem of the hybrid energy system incorporating cost functions of RES. For the model, a day-ahead forecast of wind power and solar photovoltaic power is obtained by using the Levy-Flight Chaotic Whale Optimization Algorithm optimized Extreme Learning Machines(LCWOA-ELM). The proposed algorithm is tested for the UC-CEED solution of an IEEE-39 bus system with two distinct cases: (1) without RES integration and (2) with RES integration. Several independent trial runs are executed, and the performance of the algorithms is assessed based on optimal UC schedules, fuel cost, emission quantization, convergence curve, and computational time. For case 1, the proposed algorithm resulted in a percentage reduction of 0.1021% in fuel cost and 0.7995% in emission. In contrast, for test case 2, it resulted in a percentage reduction of 0.12896% in fuel cost and 0.772% in emission with the proposed algorithm. The results validate the dominance of the proposed methodology over existing methods in terms of lower fuel costs and emissions. [ABSTRACT FROM AUTHOR]

Emissions of pollutants and their consequences for the atmosphere have received special attention from international organizations in recent years due to the climate crisis predicted in the next decades. In this regard, the Carbon Dioxide (CO2) produced in industrial sectors is one of the most concerning compounds because of its impact on global warming and climate change. This study developed a systematic review of Carbon Dioxide Emissions from manufacturing industries considering one decade of research documents focused on addressing this problem. For this, different assessments such as the trend of published articles, top-cited studies, the network evaluation of journals, and keywords network evaluation were conducted. After a careful data-driven analysis, research trends were identified. Findings revealed the increased urgency of finding and assessing information regarding the climate crisis due to CO2 emissions as well as revealing which main sectors and research areas have been involved in its investigation. Furthermore, the most influential contributions and clusters of words obtained demonstrate interrelationships among research trends that are focused on finding new paths to generate more sustainable processes in every manufacturing industry. This study aims to generate valuable insights into the role played by manufacturing industries in the context of the environmental situation, revealing trends and key points among the scientific community. [ABSTRACT FROM AUTHOR]

Inland waters are important sources of the greenhouse gases carbon dioxide (CO2) and methane (CH4). Ponds have amongst the highest CO2 and CH4 fluxes of all aquatic ecosystems, yet seasonal variation in fluxes remain poorly characterized, creating challenges for accurately estimating annual emissions. Further, ponds can exhibit a range of mixing regimes, yet the impact of mixing regimes on gas emissions remains unclear. Here, we assessed annual dynamics of CO2 and CH4 in four temperate ponds (Minnesota, USA) that varied in mixing regimes. The ponds ranged from annual sinks to sources of CO2 (−1 to 15 mol m−2 yr−1) and were all significant sources of CH4 (4.3–8.2 mol m−2 yr−1), with annual fluxes in CO2 equivalents of 1.8–4.1 kg CO2-eq. m−2 yr−1. Mixing regimes impacted CO2 and CH4 dynamics, as stratified periods were associated with more anoxia, greater accumulation of gases in the bottom waters, higher emissions of CH4, and lower fluxes of CO2. Ponds with stronger summer stratification also had increased CO2 and CH4 fluxes associated with fall turnover. Overall, the two ponds with the strongest stratification had higher annual fluxes (2.6, 4.1 kg CO2-eq. m−2 yr−1) compared to the two ponds that more frequently mixed (1.8, 2.2 kg CO2-eq. m−2 yr−1). [ABSTRACT FROM AUTHOR]

The influence of carbonization on emission characteristics of rice husk briquettes in a fixed-bed reactor were investigated in this study. Rice husk briquettes were combusted in a fixed bed operated under counterflow mode of flame propagation. Emissions levels for NOx, SOx, unburnt hydrocarbons (CxHy), CO and CO2 were measured under varying biochar and air-mass flow rate conditions. Biochar in the fuel samples were varied uniformly between 25 and 100% while air mass flux was varied uniformly between 0.02 and 0.6 kg/m2.s. It was established that carbonization increases emissions of NOx, SOx, CO2 and decreases emissions of CxHy. Briquettes with high amount of carbonized rice husks emitted high amount of NOx and SOx contrary to the amount of N and S present in these fuels indicating a stronger contribution from higher combustion temperatures. On the other hand, all emissions except CO were directly proportional to air mass flux up to stoichiometric condition which was approximately at 0.31 kg/m2.s. These findings underscore the potential of carbonized rice husk briquettes as a cleaner alternative for biomass combustion. [ABSTRACT FROM AUTHOR]

The present work proposes the application of CH 4 and H 2 synergy to improve the performance of the Wankel rotary engine (WRE). The whole work was experimentally conducted at 1500 r/min. The results indicate that CH 4 WRE can achieve similar power and significantly higher thermal efficiency than gasoline WRE based on quantitative control, with a maximum absolute efficiency improvement of 11.4%. At the same time, it also can achieve 64% and 77% maximum reduction of CO and NO emissions, respectively. CH 4 –H 2 synergy can further improve the performance of CH 4 -fueled WRE, which can broaden the lean flammability limits and make qualitative control application possible. Compared with CH 4 WRE with quantitative control, qualitative control hybrid fuel WRE can achieve a maximum relative improvement of 6.54% in brake thermal efficiency and significantly reduced NO and CO emissions. However, the extent of qualitative control is limited by cyclic variation. Overall, CH 4 –H 2 synergy can be a potential alternative to elevate the performance of WRE, the key to which is the reasonable match of synergy level and qualitative control extent. • Comparison of performances between CH4 and gasoline Wankel rotary engines. • CH4 has significant advantages in efficiency, CO and NO emission than gasoline. • CH4–H2 synergy can further improve the performance of the CH4 Wankel rotary engine. • Blending H2 coupling qualitative control is a good load control model in CH4 WRE. [ABSTRACT FROM AUTHOR]

Energy management is essential for the efficient operation of microgrids with reduced energy costs and minimized emissions. Energy management of PV/battery/fuel cell/diesel generator-based microgrid to minimize the operations cost considering battery degradation and emissions for a fully functional microgrid existing in the campus of Sultan Qaboos University, Oman, is presented in this work. A microgrid with a state-of-the-art hydroplus fuel cell without the necessity for hydrogen storage is presented in this study with experimentally obtained parameters. Also, a comparison of operations cost with microgrids using two different technologies of PEM fuel cells, one with hydroplus fuel cell and the second with the methanol fuel cell which requires provision for hydrogen storage is performed with three different cases; the scheduled, grid-tied, and islanded with different scenarios under grid-tied mode. The analysis proved that using a hydroplus fuel cell instead of a methanol fuel cell with hydrogen storage reduces the cost of the daily operation by 6.9% in the scheduled mode and 18.2% in the islanded mode. In the grid-tied mode three different grid limits, 20 kW, 15 kW, and 10 kW are considered. The analysis showed no reduction, 1.3% and 5.9% reduction in the operations cost respectively. The results obtained are highly promising to be applied in microgrids where conventional fuel cells are currently employed. The new technology of fuel cells introduced in this study, possesses the advantages of near zero emissions and reduced operations costs besides avoiding the perilousness of hydrogen storage. [Display omitted] • Energy management strategy to minimize the operations cost of microgrid is proposed. • Mathematical modelling is performed with experimentally obtained parameters. • Comparison of operations costs with two technologies of PEM fuel cells is performed. • Significant reduction in daily operations costs with hydroplus fuel cell. • Near-zero emissions in hydroplus fuel cell. [ABSTRACT FROM AUTHOR]

According to city road tests conducted during peak vehicle traffic hours, vehicle idle times constitute about 30-38% of the total running time. Therefore, when it comes to urban transportation, the fuel consumption and resulting exhaust emissions from passenger cars powered by internal combustion engines and constitute a large portion of the number of vehicles, become significant while idling. This study investigates the effects of using acetylene as fuel on the idling performance of a gasoline engine. Experiments conducted on a four-stroke, four-cylinder, water-cooled, spark-ignition automobile engine showed that using gasoline-acetylene mixtures and 100% acetylene instead of gasoline alone resulted in a decrease in carbon monoxide and hydrocarbon emissions and an increase in nitrogen oxide emission. Carbon monoxide emissions, which were 2.2% in gasoline operation, decreased to 1.1% and 0.7% with the addition of acetylene to gasoline at 100 and 150 g/h flow rates, respectively, while HC emissions, which were 895 ppm, became 576 ppm and 520 ppm. In experiments using 100% acetylene in the test engine, it was observed that there was a 96% reduction in carbon monoxide and hydrocarbon emissions and a 650% increase in nitrogen oxide emissions compared to running on gasoline. It was found that there was a 20.5% decrease in the energy flow to the engine. [ABSTRACT FROM AUTHOR]

The car market in Mexico has undergone substantial change over the last twenty years, as sales have increased dramatically and as policy measures have been introduced to improve fuel economy so that decarbonization targets can be achieved. The argument presented in this paper is that overall fuel economy is driven by vehicle sales and the fuel economy standards imposed. In addition, this picture is complicated by the purchasing preferences of buyers, and this might reduce the effectiveness of the policy measures introduced. A case study approach allows analysis of the shifts in transport policy (2003–2020) to be undertaken by linking the fuel consumption of cars (L/100 km) to the purchasing patterns of consumers, and from this estimate the levels of CO2 emissions. From the empirical analysis, it is found that, although there have been fuel economy gains every year, this is countered by (a) increasing sales of SUVs, and (b) a car market that is increasingly being dominated by larger cars. The current fuel standards are not sufficient to control the continued growth in fuel consumption, and levels of carbon emissions are continuing to increase. In conclusion, tighter emissions standards are needed, together with stronger governance structures and a range of further policy measures to improve car efficiencies and limit growth of the use of larger vehicles. [ABSTRACT FROM AUTHOR]

Fighting climate change has become a major task worldwide. One of the key energy sectors to emit greenhouse gases is transportation. Therefore, long term strategies all over the world have been set up to reduce on-road combustion emissions. In this context, the road freight sector faces significant challenges in decarbonization, driven by its limited availability of low-emission fuels and commercialized zero-emission vehicles compared with its high energy demand. In this work, we develop the Mobility and Energy Transportation Analysis (META) Model, a python-based optimization model to quantify the impact of transportation projected policies on freight transport by projecting conventional and alternative fuel technologies market acceptance as well as greenhouse gas (GHG) emissions. Along with introducing e-fuels as an alternative refueling option for conventional vehicles, META investigates the market opportunities of Mobile Carbon Capture (MCC) until 2050. To accurately assess this technology, a techno-economic analysis is essential to compare MCC abatement cost to alternative decarbonization technologies such as electric trucks. The novelty of this work comes from the detailed cost categories taken into consideration in the analysis, including intangible costs associated with heavy-duty technologies, such as recharging/refueling time, cargo capacity limitations, and consumer acceptance towards emerging technologies across different regions. Based on the study results, the competitive total cost of ownership (TCO) and marginal abatement cost (MAC) values of MCC make it an economically promising alternative option to decarbonize the freight transport sector. Both in the KSA and EU, MCC options could reach greater than 50% market shares of all ICE vehicle sales, equivalent to a combined 35% of all new sales shares by 2035. [ABSTRACT FROM AUTHOR]

With the increasing global demand for renewable energy, biodiesel has become a promising alternative to fossil fuels with significant environmental benefits. This article systematically reviews the latest advances in predictive modeling techniques for estimating the characteristics of biodiesel and its impact on diesel engine performance. Various methods for predicting the key performance of biodiesel and the performance and emissions of diesel engines have been summarized. According to the categories of parameters, research cases in recent years have been listed and discussed separately. This review provides a comprehensive overview and serves as a reference for future research and development of biodiesel. [ABSTRACT FROM AUTHOR]

The growth in population increases greenhouse gas (GHG) emissions into the environment. High GHG emissions are attributed to meat production, due to its high energy demand. The largest carbon footprint in the production of poultry meat is generated by combustion. This paper deals with the problem of greenhouse gas emissions (total dust, CO, CO2, NOx, SOx and benzo(a)pyrene) resulting from the generation of energy for heating broiler houses located in different locations in Europe. The study includes continuous measurements of selected microclimate parameters: temperature and relative humidity inside and outside the building, floor temperature, wind speed and direction, and solar radiation intensity. Validation and calibration of the model, emission calculations, and analysis of the obtained results were conducted. Eighteen design variants were assumed, differentiated by the heating fuel used (hard coal, fuel oil, gaseous fuels), material and construction solutions for the floor and the location of the facility. The analysis showed that CO2 emissions for a facility located in northern Europe are 123,153 kg higher compared to the same building located in southern Europe. In addition, increasing the floor's thermal resistance by 3.69 m2·K·W−1 reduced harmful gas emissions by an average of 5.7% for each of the locations analysed. [ABSTRACT FROM AUTHOR]

Malaysia has been struggling to effectively manage waste which accounts for a substantial amount of greenhouse gases. Thus, the objective of this study was to identify whether renewable energy from combustible renewable and waste could significantly reduce the total greenhouse gas emissions in both the short and long run in Malaysia. This study applies time series estimation techniques which cover 47 years of Malaysia's data from the year 1971–2018. The model fits VECM estimation which examines the renewable energy effect on greenhouse gas emissions in the short and long run. The empirical analysis significantly establishes that the renewable energy reduced the total greenhouse gas emissions in the long run. Statistically, a 1% increase in combustible renewable and waste (CRW) reduced the total greenhouse gas emissions by nearly 0.14% in the long run. Furthermore, arable land, methane emissions potentially reduced greenhouse gas emissions between 1971–2018. However, economic growth and carbon dioxide emissions from manufacturing industries and construction significantly increased total greenhouse gas emissions in the long run. The study concludes empirically that waste generation could be utilized to produce renewable energy through combustible renewable and waste which could slowly reduce greenhouse gas emissions. [ABSTRACT FROM AUTHOR]

Although precombustion chambers, or prechambers, have long been employed for improving large-bore two-stroke natural gas engine ignition and combustion stability, their design predates modern analysis techniques. Employing the latest computational fluid dynamics (CFD) modeling techniques, this study investigates the importance of temperature and chemistry for ignition of the main chamber, with an emphasis on eliminating unburned methane. The sensitivity of the ignition and complete combustion to main chamber air/fuel mixture homogeneity was also explored. This study compares the effect of purely thermal ignition, purely chemical ignition, and how their interplay can influence the complete combustion of methane in typical mixtures and in homogeneous distributions of fuel in the combustion chamber. The CFD results demonstrated that temperature and chemistry are equally important in the ignition mechanism, and combining the two phenomena is effective at igniting the main chamber. Reduction of residual methane in the main combustion chamber (MCC) is most effective when chemical intermediates and thermal ignition are combined. A rudimentary analysis of the effect of fuel/air stratification was also conducted, and it demonstrated that a dramatic reduction in methane emissions is observed for homogeneous mixtures. The flow field in the main combustion chamber was shown to create detrimental stratification of the fuel/air mixture, which inhibited complete combustion of the methane in the main chamber. By contrast, in the extreme case of a perfectly homogeneous distribution of both chemical intermediates and fuel in the combustion chamber, it is possible to completely eliminate unburned methane in the main combustion chamber. [ABSTRACT FROM AUTHOR]

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In this research, we document knowledge gaps between consumers and experts about what consumer actions most effectively help mitigate climate change. We then identify three sources for lack of consumer knowledge on greenhouse gas emissions associated with consumption: carbon emissions labeling, awareness of indirect versus direct emissions, and orders of magnitude differences in carbon intensity across behaviors. We further propose that this lack of knowledge and several cognitive and motivational biases lead consumers away from effective climate actions, including the tendency to focus on first- versus second-order effects of "green" behaviors, motivated reasoning that easier, more accessible actions are more impactful, and a focus on individual behavior versus systemic changes. We close with a research agenda designed to address the lack of knowledge and biases we identify, while acknowledging that shifting marketers and consumers to focus on systemic changes may be both most challenging and most impactful. [ABSTRACT FROM AUTHOR]

In the presented study, the effects on engine performance and emissions were experimentally examined by using different ratios of fuel blends and SOI changes in a single-cylinder diesel engine. Experiments were carried out at a constant engine load (%50 load) under a constant engine speed of 2400 rpm and a different SOI. Firstly, B20, T10, and T20 fuels were utilized in place of D100 in a diesel engine as alternative fuels. And then, T10 fuel was utilized instead of D100 fuel, and the impact of this change on emissions and engine performance was examined for various SOIs. Although there was a decrease in IMEP with B20 use, T10 and T20 increased IMEP compared to D100. In addition, although the fuels used instead of D100 significantly reduce CO, HC and smoke opacity, they create a partial increase in NOx emissions. Although there was an increase in NOx emissions with the use of alternative fuels, there was a decrease in the use of T10 and T20 fuels compared to B20. This reduction in NOx due to the use of T10 and T20 is important for the use of biodiesel in diesel engines. In the study, it was seen that the SOI change was effective on the results in the T10 fuel experiments, and the most suitable angle for SOI in the use of T10 fuel in diesel engines was 21°CA and 23°CA. T10 fuel has been shown to have a promising effect on engine performance and emissions. [ABSTRACT FROM AUTHOR]

The rapid accumulation of polymer waste presents a significant environmental challenge, necessitating innovative waste management and resource recovery strategies. This study investigates the potential of chemical recycling via pyrolysis of plastic waste, specifically polystyrene (PS) and polypropylene (PP), to produce high-quality pyrolytic oils (WPPOs) for use as alternative fuels. The physicochemical properties of these oils were analyzed, and their performance in a gas turbine engine was evaluated. The results show that WPPOs increase NOx emissions by 61% for PSO and 26% for PPO, while CO emissions rise by 25% for PSO. Exhaust gas temperatures increase by 12.2% for PSO and 8.7% for PPO. Thrust-specific fuel consumption (TSFC) decreases by 13.8% for PPO, with negligible changes for PSO. The environmental-economic analysis indicates that using WPPO results in a 68.2% increase in environmental impact for PS100 and 64% for PP100, with energy emission indexes rising by 101% for PS100 and 57.8% for PP100, compared to JET A. Although WPPO reduces fuel costs by 15%, it significantly elevates emissions of CO2, CO, and NOx. This research advances the understanding of integrating waste plastic pyrolysis into energy systems, promoting a circular economy while balancing environmental challenges. [ABSTRACT FROM AUTHOR]

Considering the dataset of information related to Chinese coal-fired thermal power plants during the 2005–2017 period, we initially investigated the orthogonalized response of the carbon emission to energy consumption and power generation by using Bayesian vector autoregressions and feedback solutions for impulse control technology. The results showed that the effects of energy consumption and power generation on carbon emissions were significant. The Chinese government has launched a program aimed at curbing carbon emission peaks and neutralizing or decreasing carbon emissions. The causal relationship concludes that China still needs further investment in emission abatement, improvement related to the level of openness to the outside world, and the strengthening of the construction of green zones for industrial transfer to mitigate carbon emissions. [ABSTRACT FROM AUTHOR]

Manufacturing of thermal barrier coatings (TBCs) with optimization is one way that can be adopted to mitigate the negative impact of the aviation sector on the natural environment in its near surroundings. TBCs derived from germinates are contenders for meeting the present market need for coatings that fulfill the severe requirements of tomorrow's gas turbines (GT) engines for industrial and commercial aircraft use age. To curb the issues related to emissions, researchers have continuously working on developing the coatings for jet engines parts so as to achieve maximum efficiency out of it. Plasma coating has been utilised in a variety of industrial and aerospace applications due to its improved high-temperature oxidation performance of coated objects. The manufacturing approach of TBCs leads to sustainable approach by lowering the emissions. The Yttria-stabilized zirconia (YSZ) based coatings were sprayed using a plasma spray technique in this work, with the metal substrates (SS-304) serving as the spray target. The purpose of this experimental investigation was to investigate the application of atmospheric plasma spray (APS) in order to coat an SS-304 substrate with a composite consisting of YSZ, Al2O3, and CeO2. It was noticed that coatings had been produced in a manner that was uniform across the surface of the substrate. The purpose of this research was to gain a better understanding of the qualities of YSZ/Al2O3/CeO2 plasma sprayed coatings by characterising the surface of the coatings. The developed coatings were compared with the existing coatings to understand the newly developed coatings. [ABSTRACT FROM AUTHOR]

Ecological and environmental problems resulting from fossil fuels are due to the harmful emissions released into the atmosphere. The rising interest in searching for alternative fuels like biodiesel is growing to solve these problems. Waste cooking oil (WCO) is transformed into methyl ester and combined with biodiesel in percentages of 25, 50, 75, and 100%. Research is done on the impacts of methyl ester blends on engine performance and emissions. Compared to diesel, the methyl ester combination showed 25% lower brake power and 24% loss in thermal efficiency at maximum load and 1500 rpm. However, diesel fuel showed 23% lower specific fuel consumption increase than biodiesel. Compared to diesel, methyl ester exhibits 15% lower air-fuel ratio and 4% volumetric efficiency. Biodiesel lowers CO, HC, and smoke concentrations by 12, 44, and 48%, respectively, compared to diesel. Biodiesel emits 23% higher NOx at 1500 rpm and 100% engine load. To predict the emissions and performance of different percentages of biodiesel at engine speed variation, an artificial neural network (ANN) model is presented. ANN modeling minimizes labor, time, and finances and uses nonlinear data. Predictions were produced about the brake output power, specific fuel consumption, thermal efficiency, air-fuel ratio, volumetric efficiency, and emissions of smoke, CO, HC, and NOx as a function of engine speed and blend ratio. All correlation coefficients (r) over 0.99 and R 2 values were beyond 0.98 for all variables. There were low values of MSE, MAPE, and MSLE with significant predictive ability. WCO’s biodiesel is a viable diesel engine replacement fuel. [ABSTRACT FROM AUTHOR]

In order to enhance engine combustion and emissions, inclusion of nano additives containing hydrogen is recommended due to the high viscosity, poor calorific value, atomization, and vaporization issues of biodiesel. Transesterification was used to transform sunflower oil into methyl ester. Sunflower biodiesel of 20% by volume was blended with diesel fuel, and CeO 2 nanoparticles of 100 ppm were added to blends. Hydrogen was introduced by 5 and 10 lpm from intake manifold. Diesel engine operated at 2000 rpm and loads of 15, 30, 45, and 60 N m. BSFC was decreased by 1.77%, 4.71%, and 7.19% but BTE was improved by 1.39%, 4.04%, and 7.01% when cerium oxide, 5, and 10 lpm hydrogen were added to B20, respectively. When methyl ester mixture was combined with nano additive and H 2 at 5 and 10 lpm, respectively, EGT was reduced by 2.62, 4.77, and 6.73%. B20+ CeO 2 and B20+ CeO 2 + 5 lpm, and B20+ CeO 2 + 10 lpm showed decreases of 46.51%, 56.59%, and 63.57% in CO emissions but the declines in NO x were 6.34, 13.6% and 20.71%, respectively compared to diesel oil. Inclusion of nano-doped hydrogen at 5 and 10 lpm reduced HC emissions by 12.09% and 28.57%, respectively, about diesel. Hydrogen addition of 5 and 10 lpm to CeO 2 -doped B20 improved the in-cylinder pressures by 3% and 3.52% but the maximum heat release rate increases were 3% and 3.52% respectively compared to diesel. Biodiesel from sunflower oil with 100 ppm CeO 2 with hydrogen shows reductions in emissions and combustion enhancement. [Display omitted] • Nano additive improved heat transfer and thermal conductivity capabilities. • The addition of CeO 2 shortened the ignition delay time compared to B20. • Burning fuels with H 2 content releases more energy than fuels with a much LHV. • H 2 addition enhanced ignition and combustion characteristics. • Increased gas diffusivity caused a decrease in BSFC due to the hydrogen ratio. [ABSTRACT FROM AUTHOR]

Iron emissions from human activities, such as oil combustion and smelting, affect the Earth's climate and marine ecosystems. These emissions are difficult to quantify accurately due to a lack of observations, particularly in remote ocean regions. In this study, we used long‐term, near‐source observations in areas with a dominance of anthropogenic iron emissions in various parts of the world to better estimate the total amount of anthropogenic iron emissions. We also used a statistical source apportionment method to identify the anthropogenic components and their sub‐sources from bulk aerosol observations in the United States. We find that the estimates of anthropogenic iron emissions are within a factor of 3 in most regions compared to previous inventory estimates. Under‐ or overestimation varied by region and depended on the number of sites, interannual variability, and the statistical filter choice. Smelting‐related iron emissions are overestimated by a factor of 1.5 in East Asia compared to previous estimates. More long‐term iron observations and the consideration of the influence of dust and wildfires could help reduce the uncertainty in anthropogenic iron emissions estimates. Plain Language Summary: Human activities, such as smelting and oil combustion, release smoke and particles into the atmosphere. These particles often contain iron, which not only absorbs sunlight, contributing to atmospheric warming, but also serves as a nutrient for phytoplankton in various ocean regions. However, the precise extent of human‐induced iron emissions remains uncertain due to a lack of comprehensive monitoring data. In this study, we leverage a global data set of iron observations to refine our estimates of iron emissions attributed to human activities. Additionally, we examine other co‐released substances, such as carbon and nickel, to identify specific emission sources of iron. We employ statistical techniques to distinguish human‐caused iron emissions from those originating from natural sources like dust and wildfires. Moreover, we utilize iron oxide observations to constrain emissions originating from East Asia and Norway, which are estimated to originate largely from smelting emissions. Through the analysis of long‐term data sets, we provide lower and upper bounds to human‐caused iron emissions. Furthermore, we investigate the impact of reduced observation numbers and a sparse network on the range of estimated iron emissions. Our findings highlight the critical role of observation quality in accurately assessing iron emissions from human activities. Key Points: Anthropogenic total iron emissions are constrained to a factor of 3 in most global regions using long‐term aerosol observationsThe number of sites, interannual variability, and site selection filter can affect the model‐observation comparison uncertainty by 15%–50%Smelting‐related emissions are constrained to a factor of 1.5 using iron oxide observations from East Asia [ABSTRACT FROM AUTHOR]

Urbanization affects economic production activities and energy demand, as well as lifestyle and consumption behavior, affecting carbon dioxide emissions. This study constructs the System Generalized Method of Moments (Sys-GMM) model of the impact of urbanization rate on carbon dioxide emissions based on panel data of 136 countries and regions in the world from 1990 to 2020, grounded on the extended Stochastic Impacts by Regression on Population, Affluence, and Technology (STIRPAT) model. This study found that (1) there is a negative relationship between urbanization rate and CO2 emissions from 1990 to 2020. (2) The impact of the urbanization rate on CO2 emissions is heterogeneous. An increase in urbanization rate in non-OECD countries significantly reduces CO2 emissions, while the effect is not significant in OECD countries. (3) The carbon intensity of fossil energy consumption moderates the relationship between urbanization rate and CO2 emissions, weakening the effect of urbanization rate on CO2 emissions. Based on these findings, policy recommendations such as promoting urbanization and increasing the regulation and control of fossil energy carbon intensity are proposed. [ABSTRACT FROM AUTHOR]

This study investigates the performance, combustion, and emission characteristics of a single-cylinder compression ignition engine fueled with blends of Soy methyl ester (BS100) and macauba methyl ester (BM100) biodiesels, with hydrogen addition. Biodiesel blends (BSM10 - BSM50), and hydrogen addition (2–5%) were tested at various engine loads and speeds. The optimal blend, BSM20 (80% BS100 + 20% BM100), showed up to 7.8% higher brake thermal efficiency and 6.2% lower brake-specific fuel consumption than diesel. Emissions were significantly reduced: NOx by 12.9%, HC by 22.4%, CO by 27.5%, and smoke opacity by 18.7%. Adding 5% hydrogen to BSM20 further improved performance, reducing fuel consumption by up to 3.1% and increasing thermal efficiency by 2.5%, with substantial reductions in hydrocarbon and carbon monoxide emissions. This investigation highlights the potential of sustainable biodiesel blends and hydrogen as viable alternatives to conventional diesel fuels, offering significant environmental benefits and enhanced engine performance. • Macauba-soy biodiesel studied: Performance, emissions analyzed in diesel engines. • Optimal 80-20 blend (BSM20): Enhanced efficiency, lower exhaust temperatures. • BSM20 emissions: Decreased CO, HC, NOx, smoke compared to other blends. • Improved performance: Adding 5% hydrogen to BSM20 showed benefits. • Sustainable blend: Macauba-soy biodiesel with hydrogen is a promising fuel option. [ABSTRACT FROM AUTHOR]