On-road pollutant emission and fuel consumption characteristics of buses in Beijing

On-road emission and fuel consumption (FC) levels for Euro III and IV buses fueled on diesel and compressed natural gas (CNG) were compared, and emission and FC characteristics of buses were analyzed based on approximately 28,700 groups of instantaneous data obtained in Beijing using a portable emissions measurement system (PEMS). The experimental results revealed that NOx and PM emissions from CNG buses were decreased by 72.0% and 82.3% respectively, compared with Euro IV diesel buses. Similarly, these emissions were reduced by 75.2% and 96.3% respectively, compared with Euro III diesel buses. In addition, CO2, CO, HC, NOx, PM emissions and FC of Euro IV diesel buses were reduced by 26.4%, 75.2%, 73.6%, 11.4%, 79.1%, and 26.0%, respectively, relative to Euro III diesel buses. The CO2, CO, HC, NOx, PM emissions and FC factors all decreased with bus speed increased, while increased as bus acceleration increased. At the same time, the emission/FC rates as well as the emission/FC factors exhibited a strong positive correlation with the vehicle specific power (VSP). They all were the lowest when VSP < 0, and then rapidly increased as VSP increased. Furthermore, both the emission/FC rates and emission/FC factors were the highest at accelerations, higher at cruise speeds, and the lowest at decelerations for non-idling buses. These results can provide a base reference to further estimate bus emission and FC inventories in Beijing.     

Effects of continuously regenerating diesel particulate filters on regulated emissions and number-size distribution of particles emitted from a diesel engine

The effects of continuously regenerating diesel particulate filter (CRDPF) systems on regulated gaseous emissions, and number-size distribution and mass of particles emanated from a diesel engine have been investigated in this study. Two CRDPF units (CRDPF-1 and CRDPF-2) with di erent specifications were separately retrofitted to the engine running with European steady-state cycle (ESC). An electrical low pressure impactor (ELPI) was used for particle number-size distribution measurement and mass estimation. The conversion/reduction rate (RCR) of hydrocarbons (HC) and carbon monoxide (CO) across CRDPF-1 was 83% and 96.3%, respectively. Similarly, the RCR of HC and CO and across CRDPF-2 was 91.8% and 99.1%, respectively. The number concentration of particles and their concentration peaks; nuclei mode, accumulation mode and total particles; and particle mass were highly reduced with the CRDPF units. The nuclei mode particles at downstream of CRDPF-1 and CRDPF-2 decreased by 99.9% to 100% and 97.8% to 99.8% respectively; and the particle mass reduced by 73% to 92.2% and 35.3% to 72.4%, respectively, depending on the engine conditions. In addition, nuclei mode particles increased with the increasing of engine speed due to the heterogeneous nucleation initiated by the higher exhaust temperature, while accumulation mode particles were higher at higher loads due to the decrease in the air-to-fuel ratio (A/F) at higher loads.     

Development of zerovalent iron and titania (Fe0/TiO2) composite for oxidative degradation of dichlorophene in aqueous solution: synergistic role of peroxymonosulfate (HSO5−)

Environmental Science and Pollution Research - Binary composite of zerovalent iron and titanium dioxide (Fe0/TiO2) was synthesized for the catalytic removal of dichlorophene (DCP) in the presence...     

Molecular docking and dynamics studies of cigarette smoke carcinogens interacting with acetylcholinesterase and butyrylcholinesterase enzymes of the central nervous system

The free radicals produced by cigarette smoking are responsible for tissue damage, heart and lung diseases, and carcinogenesis. The effect of tobacco on the central nervous system (CNS) has received increased attention nowadays in research. Therefore, to explore the molecular interaction of cigarette smoke carcinogens (CSC) 4-(methylnitrosamine)-1-(3-pyridyl)-1-butanol (NNAL), 4-(methylnitrosamine)-1-(3-pyridyl)-1-butanone (NNK), and N′-nitrosonornicotine (NNN) with well-known targets of CNS-related disorders, acetylcholinesterase (AChE), and butyrylcholinesterase (BuChE) enzymes, a cascade of the computational study was conducted including molecular docking and molecular dynamics simulations (MDS). The investigated results of NNAL+AChE_complex, NNK+AChE_complex, and NNK+BuChE_complex based on intermolecular energies (?G) were found to ?8.57 kcal/mol, ?8.21 kcal/mol, and ?8.08 kcal/mol, respectively. MDS deviation and fluctuation plots of the NNAL and NNK interaction with AChE and BuChE have shown significant results. Further, Molecular Mechanics Poisson-Boltzmann Surface Area (MM‐PBSA) results shown the best total binding energy (^Binding?G) ?87.381 (+/?13.119) kJ/mol during NNK interaction with AChE. Our study suggests that CSC is well capable of altering the normal biomolecular mechanism of CNS; thus, obtained data could be useful to design extensive wet laboratory experimentation to know the effects of CSC on human CNS.

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Use,exposure, and environmental impacts of pesticides in Pakistan: a critical review

Environmental Science and Pollution Research - The excessive use of pesticides is posing major threats to humans and the environment. However, the environmental exposure and impact of pesticides in...     

Manganese oxide as an effective electrode material for energy storage: a review

Environmental Chemistry Letters - Efficient materials for energy storage, in particular for supercapacitors and batteries, are urgently needed in the context of the rapid development of...     

Biochemical profiling of lead-intoxicated impaired lipid metabolism and its amelioration using plant-based bioactive compound

The aim of this study was to investigate the lead (Pb)-induced lipid metabolism impairment and its amelioration using plant-based therapeutic interventions. Pb-induced hepatotoxicity can disturb the normal levels of natural antioxidant enzymes including glutathione (GSH) and superoxide dismutase (SOD) exerting a crucial impact on membrane unsaturated fatty acids (FA), hence leading to lipid peroxidation. Furthermore, Pb toxicity can also alter the regulation of various hormones involved in the synthesis of 3-hydroxy-methyl glutaryl CoA (HMG-CoA reductase), leading to an impairment in normal levels of serum cholesterol and other associated conjugated lipid molecules such HDL-cholesterol, LDL-cholesterol and VLDL-cholesterol. In this study, the lipoprotein fractions, cholesterol, triglyceride (TGs) and biomarkers of liver functions were estimated by employing respective assay kits. The levels of antioxidant enzymes, FFAs and HMG-CoA reductase were determined by employing sandwich ELISA method. The administration of PbAc in experimental rats induced a significant disturbance in lipid profile (P < 0.05) accompanying a significant reduction in natural antioxidant defence system (P < 0.05). The significant alteration in the levels of serum antioxidant enzymes can lead to membrane lipid peroxidation that is reflected by a significantly (P < 0.05) high level of serum MDA in PbAc-induced experimental rats. However, the administration of resveratrol proved therapeutically effective in the treatment of Pb toxicity. Overall, the results of this study accompanying histopathological examination had proved the ameliorating effect of resveratrol in Pb-induced lipid metabolism impairment by adopting vitamin C as a standard therapeutic intervention.

     

Ecofriendly application of coconut coir (Cocos nucifera) extract for silk dyeing

Environmental Science and Pollution Research - The worldwide resurgence of natural dyes in all fields is due to the carcinogenic effects of effluent loads shed by synthetic industries. Coconut coir...     

Asymmetric openness-environment nexus in most open OIC countries: new evidence from quantile-on-quantile (QQ) estimation

Environmental Science and Pollution Research - Trade openness continues to have the potential to influence many parts of today’s society, including religion, transportation, lifestyle,...     

Elevated ozone phytotoxicity ameliorations in mung bean {Vigna radiata (L.) Wilczek} by foliar nebulization of silicic acid and ascorbic acid

The present work provides an insight into the development of biochemical adaptations in mung beans against ozone (O₃) toxicity. The study aims to explore the O₃ stress tolerance potential of mung bean genotypes under exogenous application of growth regulators. The seeds of twelve mung bean genotypes were grown in plastic pots under controlled conditions in the glasshouse. Six treatments, control (ambient ozone level 40–45 ppb), ambient O₃ with ascorbic acid, ambient ozone with silicic acid, elevated ozone (120 ppb), elevated O₃ with ascorbic acid (10 mM), and elevated ozone with silicic acid (0.1 mM) were applied. The O₃ fumigation was carried out using an O₃ generator. The results revealed that ascorbic acid and silicic acid application decreased the number of plants with foliar O₃ injury symptoms in different degrees, i.e., zero, first, second, third, and fourth degrees; whereas 0–4 degree symptoms represent, no symptoms, symptoms occupying?<?1/4, 1/4–1/2, 1/2–3/4, and?>?3/4 of the total foliage area, respectively. Application of ascorbic acid and silicic acid also prevented the plants from the negative effects of O₃ in terms of fresh as well as dry matter production, leaf chlorophyll, carotenoids, soluble proteins and ascorbic acid, proline, and malondialdehyde (MDA) contents. Overall, silicic acid application proved more effective in reducing the negative effects of O₃ on mung bean genotypes as compared to that of the ascorbic acid. Three mung bean genotypes (NM 20–21, NM-2006, and NM-2016) were identified to have a better adaptive mechanism for O₃ toxicity tolerance and may be good candidates for future variety development programs.