Diesel Exhaust Research Articles

Evaluation of Greenhouse Gas Emission Assessment Resulting from Processing Municipal Organic Waste into Bahan Bakar Jumputan Padat for Co-firing in Power Plants; Case Study: Bagendung Landfill Cilegon City

One type of biomass that can be used as fuel for co-firing in power plants is Bahan Bakar Jumputan Padat (BBJP)/Solid Waste Fuel. BBJP is a non-hazardous waste derivative that cannot be recycled. The production process of BBJP is strictly regulated by the Indonesian national standard (SNI) 8966:2021. The definition, characteristics and specifications of BBJP are much closer to Solid Recovered Fuel (SRF) than Refuse Derived Fuel (RDF). The utilization of BBJP reflects the dedication to reducing waste in landfills with a circular economy concept approach as well as the transition of the energy mix in Indonesia. To the present day, the production capacity of BBJP at Bagendung landfill in Cilegon City, Banten Province, has successfully produced 30 tons/day of organic municipal waste with an average BBJP product yield ranging between 11-15 tons/day. This research is intended to assess the Greenhouse Gas emissions (GHG) generated from the processing of municipal waste into BBJP. There are three main processes that produce GHG emissions, namely during bio drying processing, the use of machinery that produces emissions from electricity and the transportation process that produces combustion emissions in diesel fuel. As a result, direct GHG emissions arising from all waste processing activities into BBJP consist of 10 pollutants, namely CH4, N2O, CO, NH3, CO2, NOX, SO2, NVMOC, PM2.5 and ID(1,2,3,c,d)P. CO2 emission is the largest pollutant, accounting for 96.70% of the entire BBJP process.

Experimental assessment of catalytic biofuel effect on performance and exhaust emission of diesel engine

The present experiment is to analyze the effect of blended biodiesel of chicken fat CF10 (10% chicken fat and 90% diesel), waste cooking oil WC10 (10% waste cooking oil and 90% diesel), and combined chicken fat with waste cooking oil CF&WC10 (5% chicken fat + 5% waste cooking oil and 90% diesel) on the performance of diesel engine. The experiment is conducted at a constant compression ratio of 17, mixing 50 ppm alumina alfa (Al2O3-α) catalyst nanoparticles in each blend. The performance of biodiesel is analyzed at 25%, 50%, 75%, and 100% load conditions and is compared with pure diesel. The results show that the brake torque (BT) and brake power of CF&WC10 were found to be 22.48 Nm and 3.58 kW at full load conditions. However, the indicated thermal efficiency and BTE of CF&WC10 are at full loading conditions of 52.45% and 26.78% respectively. Because the supply of A/F ratio is 18.81, at full load condition and also lowering the brake specific fuel consumption up to 0.32 kg/kWh. Therefore, optimization of both performance and exhaust emission of an engine depends on BTE and NOx as well as HC emissions. Hence, from the emissions reduction point of view, CF&WC10 has lower emissions while achieving brake thermal efficiency similar to diesel fuel. The novelty of research shows CF&WC10 leads to enhanced performance of diesel engine compared to pure diesel fuel.

Diesel exhaust particles activate macrophages and IRF5 expression in atherosclerosis

Abstract Introduction Over 20% of global deaths related to cardiovascular disease have been attributed in part to air pollution, particularly fine particulate matter (PM2.5) (1). In highly trafficked urban areas, smaller ultrafine diesel exhaust particles (DEP) represent a significant proportion of PM2.5. DEP is associated with the progression of atherosclerosis and increased plaque susceptibility to rupture (2). We have previously shown that interferon regulatory factor 5 (IRF5) has a key role in necrotic core formation, a distinguishing feature of vulnerable atherosclerotic plaques, by rendering macrophages defective at efferocytosis (3). Pronounced elevation of IRF5 is also seen in symptomatic carotid plaques, particularly in the rupture-prone shoulder regions (4). Purpose We examined the effect of DEP on macrophage phenotype and IRF5 expression in atherosclerosis. Methods Bone marrow-derived macrophages (BMDMs) from C57BL/6 mice, differentiated with GM-CSF (to mimic inflammatory macrophages) or M-CSF (mimicking homeostatic resident macrophages) were incubated with PBS or DEP (10 µg/mL) in vitro for 18 hours. Expression of inflammatory cytokines (IL-6, IL-12α), macrophage polarisation markers CD11c (itgax, inflammatory) and CD206 (mrc1, resident anti-inflammatory) and IRF5 was quantified by real-time PCR. In addition, high fat-fed ApoE-/- mice were exposed to saline or DEP (35 µL at 1 mg/mL) twice weekly for 5 weeks by pulmonary administration. The pan-macrophage marker CD64, CD206 and IRF5 were quantified in paraffin-embedded sections of brachiocephalic artery lesions by immunohistochemistry. Results In M-CSF-differentiated murine macrophages incubated with DEP, significant fold increases in gene expression (relative to PBS control) were observed: IRF5 (1.4-fold), IL-6 (31.5-fold) and IL-12α (5.8-fold) while CD206 (0.8-fold) decreased (Figure 1a, n = 5, p<0.05, two-tailed paired t-tests). CD11c expression was unchanged. No statistically significant differences were detected in GM-CSF-differentiated macrophages. In the brachiocephalic arteries of DEP-exposed ApoE-/- mice we observed increases in CD64+ macrophages (28.2±7.4 vs 15.5±5.6) and IRF5 (16.6±3.6 vs 10.1±3.4) expression, while CD206 expression decreased (4.1±0.9 vs 11.0±1.2) in comparison to saline-exposed mice (Figure 1b mean±SD, n = 5, p<0.05, two-tailed unpaired t-tests, data expressed as % of intima area). Conclusion DEP promotes CD64+ macrophages and IRF5 expression in murine atherosclerosis, while inflammation and IRF5 is induced in vitro, but only in M-CSF-differentiated murine BMDMs. This suggests that DEP has no impact on inflammatory macrophages but could switch homeostatic resident macrophages to a more inflammatory phenotype via the activation of IRF5. Therefore, IRF5 is a promising candidate for further investigation into the initial macrophage response to inhaled particles that leads to the exacerbation of vascular disease.

Progranulin derivative attenuates lung neutrophilic infiltration from diesel exhaust particle exposure.

Air pollutants, such as diesel exhaust particles (DEPs), induce respiratory disease exacerbation with neutrophilic infiltration. Progranulin (PGRN), an epithelial cell and macrophage-derived secretory protein, is associated with neutrophilic inflammation. PGRN is digested into various derivatives at inflammatory sites and is involved in several inflammatory processes. PGRN and its derivatives likely regulate responses to DEP exposure in allergic airway inflammation. To investigate the role of PGRN and its derivatives in the regulation of responses to DEP exposure in allergic airway inflammation. A murine model of allergic airway inflammation was generated in PGRN-deficient mice, and they were simultaneously exposed to DEP followed by intranasal administration of full-length recombinant PGRN (PGRN-FL) and a PGRN-derived fragment (FBAC). Inflammatory status was evaluated by bronchoalveolar lavage fluid and histopathologic analyses. Human bronchial epithelial cells were stimulated with DEPs and house dust mites (HDMs), and the effect of FBAC treatment was evaluated by assessing various intracellular signaling molecules, autophagy markers, inflammatory cytokines, and intracellular oxidative stress. DEP exposure exaggerated neutrophilic inflammation, enhanced IL-6 and CXCL15 secretions, and increased oxidative stress in the murine model; this effect was greater in PGRN-deficient mice than in wild-type mice. The DEP-exposed mice with PGRN-FL treatment revealed no change in neutrophil infiltration and higher oxidative stress status in the lungs. On the contrary, FBAC administration inhibited neutrophilic infiltration and reduced oxidative stress. In human bronchial epithelial cells, DEP and HDM exposure increased intracellular oxidative stress and IL-6 and IL-8 secretion. Decreased nuclear factor erythroid 2-related factor 2 (Nrf2) expression and increased phosphor-p62 and LC3B expression were also observed. FBAC treatment attenuated oxidative stress from DEP and HDM exposure. FBAC reduced neutrophilic inflammation exaggerated by DEP exposure in a mouse model of allergic airway inflammation by reducing oxidative stress. PGRN and PGRN-derived proteins may be novel therapeutic agents in attenuating asthma exacerbation induced by air pollutant exposure.

An experimental investigation on enhancing diesel engine performance and emissions with cashew nut shell oil biodiesel and hydrogen fumigation

An experimental investigation on enhancing diesel engine performance and emissions with cashew nut shell oil biodiesel and hydrogen fumigation

Applying similar modeling to study vehicle exhaust transport in a confined mining space

To scientifically and effectively manage exhaust pollution in underground confined spaces and reduce hazards from personnel exhaust exposure, a systematic study of the distribution characteristics of diesel locomotive exhaust emissions in mines is needed. Aiming at large underground coal mining operations, an experimental platform for the physical simulation of vehicle exhaust transport in restricted spaces is designed and created. The Hongliulin Coal Mine in Shaanxi Province, China, is used as a prototype, and the platform consists of a coal mining face system, ventilation system, exhaust emission system, monitoring and surveillance system, and control platform. The experimental platform with carbon dioxide simulation of diesel exhaust pollution, in the role of different wind speed, the concentration of carbon dioxide is a downward trend, the wind speed is in the low wind speed on the 0.2 m of the concentration difference of 25.75%; the experimental platform exhaust transport process presents a clear “three-zone” change rule; experimental platform carbon dioxide concentration and the field nitrogen dioxide concentration change trend is consistent. The platform functions and features can provide guidance for mine exhaust management and exhaust exposure hazard prevention and control.

Particle Size and Morphological Evaluation of Airborne Urban Dust Particles by Scanning Electron Microscopy and Bidimensional Empirical Mode Analysis

Airborne particles affect the health of the population. As particles decrease in size, they can penetrate deeper into the respiratory system, reaching the terminal bronchioles and alveoli. Particles as small as 0.1 µm in diameter may translocate into the bloodstream, potentially impacting various organs. Additionally, the smaller the particle size, the longer they remain suspended in the air, thereby increasing their deleterious damages. The aim of this work is to study the size distribution of airborne particles emitted from anthropogenic sources of air pollution, with a special emphasis on estimating the distribution of micro and nanoparticles considered the most harmful to health. The Bidimensional Empirical Mode Decomposition (BEMD) algorithm was used on micrographs of the particles obtained by Scanning Electron Microscopy (SEM). BEMD is a current empirical computational tool applied to image analysis that allows extracting non-linear heterogeneous oscillations of brightness. We studied ROFA (Residual Oil Fly Ash) from industrial sources and DEP (Diesel Exhaust Particles) from vehicular emissions as airborne particles. After collecting the particles on filters, micrographs were taken using SEM at different magnifications to which the BEMD algorithm was applied. Particle size and asymmetry distributions were obtained for each mode, allowing the identification of the most deleterious particles. The methodology employed herein is relatively simple and effective for inferring the impact of airborne particulate matter on health and the environment.

Coupling Effect of Elemental Carbon and Organic Carbon on the Changes of Optical Properties and Oxidative Potential of Soot Particles under Visible Light.

Soot particles, coming from the incomplete combustion of fossil or biomass fuels, feature a core-shell structure with inner elemental carbon (EC) and outer organic carbon (OC). Both EC and OC are known to be photoactive under solar radiation. However, research on their coupling effect during photochemical aging remains limited. This study examines how the optical properties and oxidative potential (OP) of wood, coal, and diesel soot particles with varying EC and OC levels are affected by exposure to visible light. Wood soot, which has the highest OC content, showed the most significant changes in both optical properties and OP, indicating its highest sensitivity to visible light aging. Molecular composition analysis revealed that the reduction of polycyclic aromatic hydrocarbons (PAHs) and methyl-PAHs primarily affects the optical properties, while oxygenated PAHs play a major role in OP. Combined with the results from reactive oxygen species detection, it is suggested that EC initiates photoreactions by generating superoxide anions, while OC undergoes compositional changes that result in subsequent atmospheric effects. These findings enhance our understanding of the photochemical aging process of soot particles and their implications for climate and health.

Biofuel blends and nano-additives: a sustainable approach to diesel engine performance and emissions improvement

Abstract The utilization of compression ignition (CI) diesel engines has seen a substantial increase in recent years owing to their numerous advantages. However, the widespread adoption of these engines has also significantly contributed to environmental pollution issues, with diesel engines being recognized as major global contributors to exhaust emissions-related pollution. To address this issue, comprehensive research has been carried out on both emissions from diesel exhaust pollutants and advanced after-treatment technologies for emission control. This study aims to evaluate the efficiency and emissions of diesel fuel mixed with various ratios of biofuel derived from Karanja seeds (B10, B15, and B20). Among the different blends examined, B20 demonstrated superior performance in terms of brake thermal efficiency (BTE) and brake-specific fuel consumption (BSFC), along with lower levels of hydrocarbon (HC) and carbon dioxide (CO2) emissions compared to pure diesel. Further, the impact of nanoadditives, specifically titanium dioxide (TiO2), at different concentrations (80 ppm, 100 ppm, and 120 ppm), on B20 blends was evaluated. The findings indicated that B20 blended with 100 ppm of TiO2 exhibited superior performance in terms of BTE, BSFC, and lower emissions of HC, CO2, nitrogen oxides (NOx), and carbon monoxide (CO). From the results, the BTE increases from 1% to 33%, illustrating enhanced thermal efficiency under similar conditions. The average BSFC across all loads and speeds in the table is approximately 0.89 kg/kWh, while the average BTE stands at approximately 23.1%.

Impact of Nano-TiO2 Combination with Biodiesel on Diesel Engine Performance and Emissions Under Fuel Magnetism Conditioning

AbstractProblems of atomization, spray, and lower output power are due to the biodiesel’s higher viscosity. All of these aim to encourage fuel magnetism and nanoparticles addition to reduce fuel consumption. Waste cooking oil was converted to methyl ester by transesterification. To make methyl ester blend, diesel and biodiesel were mixed at volume ratio of 20%. TiO2 nanoparticles were added to biodiesel blend B20 at doses of 25 and 50 mg/L. TEM and XRD were used to characterize the nanomaterials. A magnetic coil was placed before the fuel injector to apply a magnetic field on the line of fuel. South pole of the magnetic field is located near to the fuel line, whereas the north pole is located further away. To examine the impact of these nanomaterials with fuel magnetism on engine performance and emissions using WCO biodiesel mixture, an experimental test rig was built connected to diesel engine. During testing, diesel engine operates at 1500 rpm with load variation. The average increases in BTE were 1, 1.5, 3.5, 5.5, and 6.5% but the decreases in BSFC were 1.2, 2, 4, 5, and 6% for B20 + magnet, B20 + 25 TiO2, B20 + 25 TiO2 + magnet, B20 + 50 TiO2, and B20 + 50 TiO2 + magnet, respectively, at engine load range. The average drops in CO, NOx, and HC concentrations were 16, 22, and 33%, respectively, at load range for B20 + 50 TiO2 + magnet. To improve engine performance and reduce emissions, biodiesel blend B20 from waste cooking oil with nanoTiO2 concentration of 50 ppm under magnetic field effect was recommended as a substitute fuel in diesel engine.

The Research of Diesel Engine Assembly Consistency Influence NOx Emission Based on Uniform Design Method

ABSTRACT Diesel engines need to meet the higher emission requirement according to the Euro VI emission standards, and changes in the assembly tolerance of diesel engines will affect the consistency of nitrogen oxides(NOx) emissions. To study the influence of assembly tolerance on NOx emission, a heavy diesel engine was used as the research prototype. The combustion model of the diesel engine was simulated by the Converge software and calibrated with the bench test data. Because the combustion system parameters have a significant impact on emissions, a three-factor eleven-level uniform design is arranged with three parameters, including compression ratio, fuel injection nozzle extension height and injection advance angle. The regression analysis method is used to obtain the relationship between the parameters and NOx emissions. The R2 test value of the regression equation is 0.916 and the F test value is 43.5, which shows that the results of the analysis are very effective. Then the single factor test method is applied to analyze the varying laws of compression ratio, nozzle extension height and fuel injection advance angle on NOx emissions, and the results reveal the inherent law similar to the regression equation. According to the Euro VI emission standards and the law of diesel engine emission performance consistency, the tolerance variation range of the key dimensions of the assembly parameters is obtained.

Effects of Water Injection in Diesel Engine Emission Treatment System—A Review in the Light of EURO 7

Water in the engine/combustion chamber is not a novel phenomenon. Even humidity has a major effect on internal combustion engine emissions and can thus be considered the first invisibly present emission technology. With modern techniques, the problematic aspects of water, such as corrosion and lubrication issues, seem to disappear, and the benefits of water’s effect in combustion may also be enhanced in the context of EURO 7. The current study examines the literature on the effects of water on diesel combustion in chronological sequence, focusing on changes over the last three decades. Then it analyzes and re-evaluates the water effect in the current technology and the forthcoming Euro 7 regulatory context, comparing the conclusions with current automotive applications and mobility trends, in order to show the possible benefits and prospective research avenues in this sector. Techniques introducing water to combustion could be a major approach in terms of the EURO 7 retrofit mandate, as well as a feasible technique for concurrent nitrogen oxides and particulate reduction.

Prediction of Performance and Emissions Diesel Engines Fueled-Biodiesel Using Artificial Neural Network (ANN) Resilient Backpropagation Algorithm (Rprop)

In order to increase energy security and improve environmental quality, the Indonesian Goverment set a target of 23% renewable energy mix in 2025, one of which is the Mandatory Bioediesel Program. A higher biodiesel blending ratio will affect the performance and emissions of diesel engines because biodiesel is chemically different from diesel oil. Research related to the prediction of diesel engine performance and emissions using Artificial Neural Network (ANN) has been conducted, but the author sees a research opportunity for the implementation of the ANN Resilient Backpropagation (Rprop) algorithm. The data used to create the ANN model prediction was secondary data from previous research. The model designed multi input and multi output (MIMO) with 4 input variables and 7 output variables. Model building done by varying the number of neurons and hidden layers. Model evaluation selected based on the largest coefficient of determination parameter R2 and the smallest RMSE or MAPE. The results showed that the ANN single layer 4-20-7 network architecture is the best model for predicting diesel engine performance and emissions with test data R2 , RMSE and MAPE of 0.962532, 6.699428 and 6.0% respectively, while for overall data testing has a performance of 0.982869, 3.908542 and 4.3%. The results also show that based on the ANN prediction results, the increasing biodiesel ratio can increase NOx emissions and decrease HC, CO and CO emissions2 . In terms of performance, the addition of biodiesel can increase BSFC and BP and decrease BTE. The results also show that the addition of ZnO concentration can reduce emissions while in terms of performance it will increase BTE and reduce BSFC and BP.

Optimization control strategy for diesel urea-selective catalytic reduction (SCR) urea injection based on the interior point method (IP) + higher order SCR model

In order to ensure that the NOx and NH3 emissions of diesel engines comply with the Euro VII emission standards, this paper optimizes the urea injection using a SCR model combined with the interior point method. First, the equations of the higher-order SCR model were simplified by the variable substitution method and the line method and solved by the backward difference formula to improve computational accuracy. The Levenberg-Marquardt algorithm was used to calibrate the chemical reaction rate parameters to optimize model performance. Second, an optimization cost function was designed to optimize the upstream NH3 concentration in combination with the interior point method and the higher-order SCR model to meet the requirements of Euro VII emission standards. Third, the model effect was verified by performing WHTC hot-start testing on an engine complying with the National VI emission standard. The results show that the average error between the measured NOx concentration and the calculated is 1.49 ppm, which verifies the high accuracy of the model. Finally, the effects of the interior point method, NSGA-II, and MOPSO algorithms in optimizing the upstream NH3 concentration were compared. The results showed that the interior point method outperformed the other algorithms in terms of optimization time and effect, with an optimization time of 149 s, a NOx conversion rate of 97.36 %, and an average downstream NH3 concentration of 4.65 ppm. This achieved a high NOx conversion rate and low NH3 slip in accordance with the requirements of the Euro VII regulation.

Prediction and Simulation of Biodiesel Combustion in Diesel Engines: Evaluating Physicochemical Properties, Performance, and Emissions

Environmental and energy sustainability concerns have catalyzed a global transition toward renewable biofuel alternatives. Among these, biodiesel stands out as a promising substitute for conventional diesel in compression-ignition engines, providing compatibility without requiring modifications to engine design. A comprehensive understanding of biodiesel’s physical properties is crucial for accurately modeling fuel spray, atomization, combustion, and emissions in diesel engines. This study focuses on predicting the physical properties of PODL20 and EB100, including liquid viscosity, density, vapor pressure, latent heat of vaporization, thermal conductivity, gas diffusion coefficients, and surface tension, all integrated into the CONVERGE CFD fuel library for improved combustion simulations. Subsequently, numerical simulations were conducted using the predicted properties of the biodiesels, validated by experimental in-cylinder pressure data. The prediction models demonstrated excellent alignment with the experimental results, confirming their accuracy in simulating spray dynamics, combustion processes, turbulence, ignition, and emissions. Notably, significant improvements in key combustion parameters, such as cylinder pressure and heat release rate, were recorded with the use of biodiesels. Specifically, the heat release rates for PODL20 and EB100 reached 165.74 J/CA and 140.08 J/CA, respectively, compared to 60.2 J/CA for conventional diesel fuel. Furthermore, when evaluating both soot and NOx emissions, EB100 displayed a more balanced performance, achieving a significant reduction in soot emissions of 34.21% alongside a moderate increase in NOx emissions of 45.5% compared to diesel fuel. In comparison to PODL20, reductions of 20.4% in soot emissions and 3% in NOx emissions were also noted.

EVALUATING PERFORMANCE, COMBUSTION, AND EMISSION CHARACTERISTICS OF WASTE PLASTIC OIL BLENDS IN CRDI DIESEL ENGINES USING DATA ENVELOPMENT ANALYSIS

As fossil fuels run out quickly, researchers studying engines are increasingly interested in alternative fuels. This paper covers the use of plastic paralysis oil as biodiesel in diesel engines. This was done using a four-stroke, multi-cylinder CRDI diesel engine running between 2000 and 2500 rpm. From zero loads to fifty percent load, the performance, combustion, and emission characteristics were computed for a variety of load scenarios. The analysis revealed that the blend D80WPO20 at 2000 rpm reduced hydrocarbon emissions from 0.059 g/kW to 0.045 g/kW, which is lower than that of 25% diesel at 26 kW. At high speed, the blend D80WPO20 at 2000 rpm gave the maximum BTE of 34.53%. The nitric oxide (NOx) emissions from D50WPO50 and diesel at a 26 kW load are 6.48 g/kWh and 5.37 g/kWh, respectively, according to reports. Data envelopment analysis, a multi-response linear programming optimization tool, was used to evaluate the output and emissions of DI diesel engines using waste plastic oil mixtures.

The Toxic Effects of Petroleum Diesel, Biodiesel, and Renewable Diesel Exhaust Particles on Human Alveolar Epithelial Cells.

The use of alternative diesel fuels has increased due to the demand for renewable energy sources. There is limited knowledge regarding the potential health effects caused by exhaust emissions from biodiesel- and renewable diesel-fueled engines. This study investigates the toxic effects of particulate matter (PM) emissions from a diesel engine powered by conventional petroleum diesel fuel (SD10) and two biodiesel and renewable diesel fuels in vitro. The fuels used were rapeseed methyl ester (RME), soy methyl ester (SME), and Hydrogenated Vegetable Oil (HVO), either pure or as 50% blends with SD10. Additionally, a 5% RME blend was also used. The highest concentration of polycyclic aromatic hydrocarbon emissions and elemental carbon (EC) was found in conventional diesel and the 5% RME blend. HVO PM samples also exhibited a high amount of EC. A dose-dependent genotoxic response was detected with PM from SD10, pure SME, and RME as well as their blends. Reactive oxygen species levels were several times higher in cells exposed to PM from SD10, pure HVO, and especially the 5% RME blend. Apoptotic cell death was observed in cells exposed to PM from SD10, 5% RME blend, the 50% SME blend, and HVO samples. In conclusion, all diesel PM samples, including biodiesel and renewable diesel fuels, exhibited toxicity.

Emission inventory of IVOCs from diesel engine emissions in China based on real-world measured data

Intermediate volatility organic compounds (IVOCs), recognized as significant precursors of secondary organic aerosols, play a pivotal role in environmental pollution. This study utilized measured real-world emission factors to construct an inventory of IVOC emissions from diesel engines and to analyze their spatial distribution across China in 2022. Furthermore, the emission inventory derived from this approach was compared with that obtained through the IVOC/primary organic aerosol (POA) ratio method. The following findings were observed: (1) In 2022, the total IVOC emissions from diesel engines in China amounted to approximately 430 Gg, surpassing those emitted by gasoline engines and residential solid fuel combustion. Specifically, the IVOC emissions attributed to on-road diesel vehicles, inland vessels, agricultural machinery, and non-road construction machinery were recorded at 377, 39.3, 10.4 and 3 Gg, respectively. (2) In terms of geographical distribution in 2022, IVOC emissions from diesel engines were predominantly concentrated in Eastern, Southern and Northern China; on-road diesel vehicle emissions were primarily located within logistics hubs or regions characterized by extensive national and arterial road networks; while non-road construction and agricultural machinery emissions were largely confined to Eastern and Central China. Emissions from inland vessels exhibited a more distinct regional pattern concentrated mainly within the Yangtze River Delta, Pearl River Delta, and Bohai Rim areas. (3) A comparative analysis between the inventory established using real-world measured emission factors and that derived via IVOC/POA ratios indicated that the latter methodology may have overestimated emissions associated with inland vessels and non-road construction machinery. Moving forward, reducing IVOC emissions from diesel engines is crucial for enhancing air quality and safeguarding human health-particularly concerning heavy-duty vehicles, light-duty vehicles, and inland vessels.

Investigation of the optimal timing and amount of fuel injection on the efficiency and emissions of a diesel engine through experimentation and numerical analysis

The purpose of this study is to investigate the performance, in-cylinder combustion, and emissions of the MTE660E heavy-duty diesel engine using 3D CFD simulation. The CFD simulation model based on AVL FIRE software was developed to numerically investigate the performance, in-cylinder combustion, and emissions of the MTE660E engine. The AVL model was validated against empirical data. The 6-cylinder MTE660E engine was operated under a constant excess air ratio of 1.75 and at 1600 rpm engine speed. The geometry and lattice design of the MTE660E engine were simulated to provide a computationally efficient approach. The AVL model was validated against experimental data and the error between the measured and calculated value of combustion characteristics and emissions was acceptable (R2> 90 %), error <5.6 %). Design Expert software was used to optimize the dependent variables (peak chamber temperature, brake mean effective pressure, engine torque, engine thermal efficiency and emissions of NOx) according to the studied variables (injection time and fuel injection quantity) based on response surface methodology. The results show that the recommended injecting time of 342 °C and the specific amount of fuel lead to better combustion efficiency, resulting in high engine performance and low emissions. The specific fuel consumption was highest at 2200 rpm with a 50 % load, while the lowest SFC level was observed at 1750 rpm with a 100 % load. The maximum value of NOx emissions was observed at full load. The findings show that the optimization of the injection timing and fuel injection quantity can effectively enhance the performance of the MTE660E engine. The study provides valuable insights into improving combustion efficiency, resulting in greater performance and reduced emissions without requiring expensive overhaul. It has potential applications in automotive and commercial transportation industries, thereby reducing fuel consumption and emissions.

Exposure to diesel-related particulate matter, cortisol stress responsivity, and depressive symptoms in adolescents

Exposure to air pollution is associated with higher risk for psychopathology; however, the mechanisms underlying this association are not clear. Dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis in response to stress has been implicated in depression. Here, we estimated annual exposure to particulate matter (PM) from diesel emissions in 170 9- to 15-year-old adolescents (56 % female) using their residential addresses and data from nearby monitoring sites. We obtained salivary cortisol samples from participants while they completed a social stress task and calculated area under the curve with respect to ground (AUCg) and with respect to increase (AUCi) in order to assess cortisol responsivity during stress. Participants also reported on their depressive symptoms and sleep disturbances. Greater exposure to diesel PM was associated with lower cortisol output (AUCg) during stress, which was associated with higher depressive symptoms, particularly for adolescents with more sleep disturbances. Importantly, these effects were independent of household and neighborhood socioeconomic disadvantage and exposure to early adversity. Thus, HPA-axis dysfunction may be one mechanism through which environmental pollutants affect adolescents’ mental health.