Search

Abstract To fill the blank on vertical profiles of carbonaceous aerosols during winter, the first in situ vertical measurements of organic and elemental carbon (OC, EC) from ground level to 620 m were conducted by means of high topographic relief in a typical valley city of Lanzhou, northwest China. The key factors (meteorology and sources) affecting the vertical distributions also were revealed by clustering technique and principal component analysis. Mean OC and EC concentrations were (16.2 ± 8.9) μg m−3 and (5.1 ± 2.1) μg m−3 during the study periods near the ground. More uniformly vertical distributions of carbonaceous aerosols during daytime than those during nighttime with OC (EC) decreasing rates of ∼1.45 (∼0.32) μg m−3 100 m−1 during nighttime and ∼0.84 (∼0.09) μg m−3 100 m−1 during daytime. Three distinct types of OC (EC) vertical profiles were determined by clustering technique. The cluster with high concentrations of OC (33.7 ± 5.7 μg m−3) and EC (10.5 ± 7.7 μg m−3) near the ground surface was induced largely by temperature inversion around the ground. The OC (EC) differences between the surface and the hilltop increased by 14.21 (2.45) μg m−3 when inversion layer depth increased by 100 m. Winter carbonaceous aerosols were more significantly affected by atmospheric stratification near the ground, while those were impacted together by vertical and horizontal dispersions at the hilltop. The primary emissions from coal combustion or biomass burning for heating at the hilltop and motor vehicles near the ground also had an important effect on OC (EC) vertical profiles. The emissions from coal burning and gasoline vehicles accounted for 60%–70% of carbonaceous aerosols in urban areas of Lanzhou. Furthermore, the contributions of gasoline vehicles during daytime near the surface (∼20%) and biomass burning at the hilltop (∼15%) were larger due to the impact of human activities. Highlights • PM 1 OC (EC) vertical profiles were revealed in urban Lanzhou for the first time. • OC (EC) decreasing rates were ∼1.45 (∼0.32) μg m−3 100 m−1 during nighttime. • Winter OC (EC) was more largely affected by stratification near the ground. • Coal burning and gasoline vehicles emissions accounts for 60%–70% of OC (EC). • Contribution of SOC to OC was large when air pollution was severe. [ABSTRACT FROM AUTHOR]

The relative importance of contributions of gasoline vehicles (GVs) and diesel vehicles (DVs), heavy-duty diesel vehicles (HDDVs) and non-HDDVs to on-road vehicle emissions remains unclear. Vehicle emission factors (EFs), including fine particulate matter (PM 2.5 ), NO-NO 2 -NO x , and carbon monoxide (CO), were measured (August 4-18, 2017) in an urban tunnel in Tianjin, northern China. The average EFs (mg km −1 veh −1 ) of the fleet were as follows: 9.21 (95% confidence interval: 1.60, 23.07) for PM 2.5 , 62.08 (21.21, 138.25) for NO, 20.42 (0.79, 45.48) for NO 2 , 83.72 (26.29, 162.87) for NO x , and 284.54 (18.22, 564.67) for CO. The fleet-average EFs exhibited diurnal variations, due to diurnal variations in the proportion of HDDVs in the fleet, though the hourly proportion of HDDVs never exceeded 10% during the study period. The reconstructed average EFs for on-road vehicle emissions of PM 2.5 , NO, NO 2 , and NO x , and CO were approximately 2.2, 1.7, 1.5, 2.0, and 1.6 times as much as those in the tunnel, respectively, due to the higher HDDV fractions in the whole city than those in the tunnel. The EFs of PM 2.5 , NO, NO 2 , and NO x , and CO from each HDDV were approximately 75, 81, 24, 65, and 33 times of those from each non-HDDV, respectively. HDDVs were responsible for approximately 81.92%, 83.02%, 59.79%, 79.79%, and 66.77% of the total PM 2.5 , NO, NO 2 , and NO x , and CO emissions from on-road vehicles in Tianjin, respectively. DVs, especially HDDVs, are major sources of on-road PM 2.5 , NO-NO 2 -NO x , and CO emissions in northern China. The contribution of HDDVs to fleet emissions calculated by the EFs from Chinese ‘on-road vehicle emission inventory guidebook’ were underestimated, as compared to our results. The EFs from on-road vehicles should be updated due to the rapid progression of vehicle technology combined with emission standards in China. The management and control of HDDV emissions have become urgent to reduction of on-road vehicle emissions. [ABSTRACT FROM AUTHOR]

Abstract Consequences of pseudoreplication or the sole use of plot averages even within one ecosystem on the reliability of laboratory remediation tests have barely been studied even though they may mask field variability. Soils from three field plots were tested separately to reveal the consequences of inadequate use of replicates. Parallel remediation experiments consisting of treatments control (non-contaminated soil), natural attenuation (gasoline-contaminated soil) and biostimulation (gasoline-contaminated and methylene urea fertilized soil) were conducted to each plot soil. Three destructive sampling days and three pseudoreplicates per treatment, per plot and per sampling day were designed. The concentrations of total and individual gasoline aromatics were followed using both within-plot pseudoreplicates and plot averages. Results showed that natural attenuation of total or individual gasoline aromatics depended on field plots and that fertilization showed enhancing, inhibiting and negligible effects, respectively, also depending on field plots. Additionally, plot averages masked within-treatment variation between field plots. Conclusively, within-plot pseudoreplication using a single field plot or interpretations based solely on plot averages cannot reveal remediation patchiness observed in practice. Due to the high soil heterogeneity, ecological between-plot replication together with the parallel analysis of each replicate is encouraged in laboratory studies aiming to design in situ remediation strategies. Highlights • Pseudoreplication or plot averages alone masked variability in soil remediation. • Remediation results of one field plot could not be generalized to other field plots. • Fertilization effect was plot dependent in altering soil remediation properties. • Plot averages led to false positives/negatives in soil remediation outcomes. [ABSTRACT FROM AUTHOR]

Ultrafine (<100 nm) particles related to traffic are of high environmental and human health concern, as they are supposed to be more toxic than larger particles. In the present study transmission electron microscopy (TEM) is applied to obtain a concrete picture on the nature, morphology and chemical composition of non-volatile ultrafine particles in the exhaust of state-of-the-art, Euro 6b, Gasoline and Diesel vehicles. The particles were collected directly on TEM grids, at the tailpipe, downstream of the after-treatment system, during the entire duration of typical driving cycles on the chassis dynamometer. Based on TEM imaging coupled with Energy Dispersive X-ray (EDX) analysis, numerous ultrafine particles could be identified, imaged and analyzed chemically. Particles <10 nm were rarely detected. The ultrafine particles can be distinguished into the following types: soot, ash-bearing soot and ash. Ash consists of Ca, P, Mg, Zn, Fe, S, and minor Sn compounds. Most elements originate from lubricating oil additives; Sn and at least part of Fe are products of engine wear; minor W ± Si-bearing nearly spherical particles in Diesel exhaust derive from catalytic coating material. Ultrafine ash particles predominate over ultrafine soot or are nearly equal in amount, in contrast to emissions of larger sizes where soot is by far the prevalent particle type. This is probably due to the low ash amount per volume fraction in the total emissions, which does not favor formation of large ash agglomerates, opposite to soot, which is abundant and thus easily forms agglomerates of sizes larger than those of the ultrafine range. No significant differences of ultrafine particle characteristics were identified among the tested Gasoline and Diesel vehicles and driving cycles. The present TEM study gives information also on the imaging and chemical composition of the solid fraction of the unregulated sub-23 nm size category particles. [ABSTRACT FROM AUTHOR]

Communities resident in urban areas located near active volcanoes can experience volcanic ash exposures during, and following, an eruption, in addition to sustained exposures to high concentrations of anthropogenic air pollutants ( e.g., vehicle exhaust emissions). Inhalation of anthropogenic pollution is known to cause the onset of, or exacerbate, respiratory and cardiovascular diseases. It is further postulated similar exposure to volcanic ash can also affect such disease states. Understanding of the impact of combined exposure of volcanic ash and anthropogenic pollution to human health, however, remains limited. The aim of this study was to assess the biological impact of combined exposure to respirable volcanic ash (from Soufrière Hills volcano (SHV), Montserrat and Chaitén volcano (ChV), Chile; representing different magmatic compositions and eruption styles) and freshly-generated complete exhaust from a gasoline vehicle. A multicellular human lung model (an epithelial cell-layer composed of A549 alveolar type II-like cells complemented with human blood monocyte-derived macrophages and dendritic cells cultured at the air-liquid interface) was exposed to diluted exhaust (1:10) continuously for 6 h, followed by immediate exposure to the ash as a dry powder (0.54 ± 0.19 μg/cm 2 and 0.39 ± 0.09 μg/cm 2 for SHV and ChV ash, respectively). After an 18 h incubation, cells were exposed again for 6 h to diluted exhaust, and a final 18 h incubation (at 37 °C and 5% CO 2 ). Cell cultures were then assessed for cytotoxic, oxidative stress and (pro-)inflammatory responses. Results indicate that, at all tested (sub-lethal) concentrations, co-exposures with both ash samples induced no significant expression of genes associated with oxidative stress ( HMOX1, NQO1 ) or production of (pro-)inflammatory markers (IL-1β, IL-8, TNF-α) at the gene and protein levels. In summary, considering the employed experimental conditions, combined exposure of volcanic ash and gasoline vehicle exhaust has a limited short-term biological impact to an advanced lung cell in vitro model. [ABSTRACT FROM AUTHOR]

Concerns over carbon emissions have motivated motorcycle producers to explore the use of electric energy instead of gasoline. Due to battery capacity limitations, electric energy consumption should be optimized to extend the range of Electric Motorcycles (EMCs). Road curvature is an inevitable part of motorcycle travel, and this paper proposes a detailed electric motorcycle model to calculate electric energy consumption on both straight curved roads. Simulation results show that road curvature has a significant effect on energy consumption, so a Dynamic Programming (DP) optimization strategy was used to calculate EMC optimized speed over curved roads. [ABSTRACT FROM AUTHOR]

Gasoline direct injection (GDI) vehicles quickly replace traditional port-fuel injection (PFI) vehicles in Europe reaching about 50 million vehicles on roads in 2020. GDI vehicles release large numbers of soot nanoparticles similar to conventional diesel vehicles without particle filters. These exhausts will increasingly affect air quality in European cities. We hypothesized that such particles are released together with polycyclic aromatic hydrocarbons (PAHs) formed under the same combustion conditions. Emission data of a fleet of 7 GDI vehicles (1.2–1.8 L) including Euro-3,-4,-5 and -6 technologies revealed substantial particle emissions on average of 2.5 × 10 12 particles km −1 in the cold worldwide harmonized light vehicle test cycle (cWLTC), the future European legislative driving cycle. Particle emissions increased 2–3 orders of magnitude during acceleration like CO, indicating that transient driving produces fuel-rich conditions with intense particle formation. For comparison, an Euro-5 diesel vehicle (1.6 L) equipped with a particle filter released 3.9 × 10 10 particles km −1 (cWLTC), clearly within the Euro-5/6 limit value of 6.0 × 10 11 particles km −1 and 64-fold below the GDI fleet average. PAH and alkyl-PAH emissions of the GDI vehicles also exceeded those of the diesel vehicle. Mean GDI emissions of 2-, 3-, 4-, 5- and 6-ring PAHs in the cWLTC were 240, 44, 5.8, 0.5 and 0.4 μg km −1 , those of the diesel vehicle were only 8.8, 7.1, 8.6, 0.02 and 0.02 μg km −1 , respectively. Thus mean PAH emissions of the GDI fleet were 2 orders of magnitude higher than the bench mark diesel vehicle. A comparison of the toxicity equivalent concentrations (TEQ) in the cWLTC of the GDI fleet and the diesel vehicle revealed that GDI vehicles released 200–1700 ng TEQ m −3 genotoxic PAHs, being 6–40 times higher than the diesel vehicle with 45 ng TEQ km −1 . The co-release of genotoxic PAHs adsorbed on numerous soot nanoparticles is critical due to the Trojan horse effect describing the property of sub-200 nm particles being deposited in the alveoli transporting genotoxic compounds into the lung. These nanoparticles are persistent and may eventually penetrate the alveolar membrane reaching the blood circulation system. We showed that all GDI vehicles tested released large numbers of nanoparticles carrying substantial loads of genotoxic PAHs. If non-treated diesel exhaust is considered as class-1 carcinogen by the WHO inducing lung cancer in humans, these GDI vehicle exhausts may be a major health risk too for those exposed to them corroborating the progress achieved with current diesel vehicles, now equipped with efficient particle filters. [ABSTRACT FROM AUTHOR]

Gasoline vehicles are a major source of anthropogenic secondary organic aerosols (SOAs). However, current models based on known precursors fail to explain the substantial SOAs from vehicle emissions due to the inadequate understanding of the formation mechanism. To provide more information on this issue, the formation of SOAs from ozonolysis of four light-duty gasoline vehicle exhaust systems was investigated with a vacuum ultraviolet photoionization mass spectrometer (VUV-PIMS). Remarkable SOAs formation was observed and the SOAs were primarily aliphatic alkenes. PI mass spectra of the SOAs from all vehicles exhibited similar spectral patterns (a regular mass group with m/z at 98, 112, 126 …). Interestingly, most carbonyl products of aliphatic alkenes observed as major gaseous products have specific molecular weights, and the main formation pathway of SOAs can be explained well using aldol condensation reactions of these carbonyls. This is a direct observation of the aldol condensation as a dominated pathway for SOAs formation, and the first report on the composition and formation mechanism of the SOAs from the ozonolysis of gasoline vehicle exhaust is given. The study reveals that low molecular weight alkenes may play a more significant role in vehicle-induced SOAs formation than previously believed. More importantly, the PI mass spectra of SOAs from vehicles show similarities to the field aerosol sample mass spectra, suggesting the possible significance of the aldol condensation reactions in ambient aerosol formation. Since carbonyls are a major degradation product of biogenic and anthropogenic VOCs through atmospheric oxidation processes, the mechanism proposed in this study can be applied more generally to explain aerosol formation from the oxidation of atmospheric hydrocarbons. [ABSTRACT FROM AUTHOR]

Heating value has been one of the important properties of gasoline surrogate fuel being investigated for thermal conversion system inside combustion cylinder. Alternative fuel yielded from biomass is expected to have lower energy content than baseline fuel (gasoline), as several factors were analysed such as molecular structure and carbon contents. Qualifying fuel's heating value properties can serve the researchers who work on different alternative fuels to indicate the fuel suitability for spark-ignition engines according to fuel standards. This research work was conducted to study the effects of alcohol blends (methanol, ethanol and iso-butanol) at different volume percentages (0-25%) with an interval of 2.5% on the heating value of gasoline fuel. A non-linear relationship was observed for heating value of each fuel blend generated from statistical polynomial regressions with the highest order of two. Polynomial equations derived were expected to be highly accurate in estimating the properties of heating value of the fuel blends as the coefficient of determination obtained for methanol, ethanol and iso-butanol blends were 0.9445, 0.9691 and 0.692, respectively. Analysis based on the percentage error was done using average absolute error and average bias error with those blends producing lower than 2% error. The estimation model is suggested to be used as it produces highly accurate and precise results for the alcohol-gasoline blends. [ABSTRACT FROM AUTHOR]

To further explore the composition and distribution of secondary organic aerosol (SOA) components from the photo-oxidation of light aromatic precursors (toluene, m -xylene, and 1,3,5-trimethylbenzene (1,3,5-TMB)) and idling gasoline exhaust, a vacuum ultraviolet photoionization mass spectrometer (VUV-PIMS) was employed. Peaks of the molecular ions of the SOA components with minimum molecular fragmentation were clearly observed from the mass spectra of SOA, through the application of soft ionization methods in VUV-PIMS. The experiments comparing the exhaust-SOA and light aromatic mixture-SOA showed that the observed distributions of almost all the predominant cluster ions in the exhaust-SOA were similar to that of the mixture-SOA. Based on the characterization experiments of SOA formed from individual light aromatic precursors, the SOA components with molecular weights of 98 and 110 amu observed in the exhaust-SOA resulted from the photo-oxidation of toluene and m -xylene; the components with a molecular weight of 124 amu were derived mainly from m -xylene; and the components with molecular weights of 100, 112, 128, 138, and 156 amu were mainly derived from 1,3,5-TMB. These results suggest that C 7 -C 9 light aromatic hydrocarbons are significant SOA precursors and that major SOA components originate from gasoline exhaust. Additionally, some new light aromatic hydrocarbon-SOA components were observed for the first time using VUV-PIMS. The corresponding reaction mechanisms were also proposed in this study to enrich the knowledge base of the formation mechanisms of light aromatic hydrocarbon-SOA compounds. [ABSTRACT FROM AUTHOR]

Speed variations are considered as an alternative for reducing fuel consumption during the use phase of passenger cars. It explores vehicle engine operating zones with lower fuel consumption, thus making possible a reduction in fuel consumption when compared to constant speed operation. In this paper, we present an evaluation of two conditions of speed variations: 50–70 km/h and 90–110 km/h using numerical simulations and controlled tests. The controlled tests performed on a test track by a professional pilot show that a reduction in fuel consumption is achievable with a conventional gasoline passenger car, with no adaptations for realizing speed variations. Numerical simulations based on a backward quasi-static powertrain model are used to evaluate the potential of speed variations for reducing fuel consumption in other speed variation conditions. When deceleration is performed with gear in neutral position, simulations show that speed variations are always correlated to a lower fuel consumption. This was suspected through previous numerical tests or evaluation on test bench but not in controlled tests conditions. [ABSTRACT FROM AUTHOR]

In this work, a comprehensive characterisation and source apportionment of size-segregated aerosol collected using a multistage cascade impactor was performed. The samples were collected during wintertime in Milan (Italy), which is located in the Po Valley, one of the main pollution hot-spot areas in Europe. For every sampling, size-segregated mass concentration, elemental and ionic composition, and levoglucosan concentration were determined. Size-segregated data were inverted using the program MICRON to identify and quantify modal contributions of all the measured components. The detailed chemical characterisation allowed the application of a three-way (3-D) receptor model (implemented using Multilinear Engine) for size-segregated source apportionment and chemical profiles identification. It is noteworthy that - as far as we know - this is the first time that three-way source apportionment is attempted using data of aerosol collected by traditional cascade impactors. Seven factors were identified: wood burning, industry, resuspended dust, regional aerosol, construction works, traffic 1, and traffic 2. Further insights into size-segregated factor profiles suggested that the traffic 1 factor can be associated to diesel vehicles and traffic 2 to gasoline vehicles. The regional aerosol factor resulted to be the main contributor (nearly 50%) to the droplet mode (accumulation sub-mode with modal diameter in the range 0.5–1 μm), whereas the overall contribution from the two factors related to traffic was the most important one in the other size modes (34–41%). The results showed that applying a 3-D receptor model to size-segregated samples allows identifying factors of local and regional origin while receptor modelling on integrated PM fractions usually singles out factors characterised by primary (e.g. industry, traffic, soil dust) and secondary (e.g. ammonium sulphate and nitrate) origin. Furthermore, the results suggested that the information on size-segregated chemical composition in different size classes was exploited by the model to relate primary emissions to rapidly-formed secondary compounds. [ABSTRACT FROM AUTHOR]

Mitigating black carbon (BC) emissions from various combustion sources has been considered an urgent policy issue to address the challenges of climate change, air pollution and health risks. Vehicles contribute considerably to total anthropogenic BC emissions and urban BC concentrations. Compared with heavy-duty diesel vehicles, there is much larger uncertainty in BC emission factors for light-duty passenger vehicles (LDPVs), in particular for gasoline LDPVs, which warrants further studies. In this study, we employed the dynamometer and the Aethalometer (AE-51) to measure second-by-second BC emissions from eight LDPVs by engine technology and driving cycle. The average BC emission factors under transient cycles (e.g., ECE-15, New European Driving Cycle, NEDC, Worldwide Harmonized Light Vehicles Test Cycle, WLTC) are 3.6–91.5 mg/km, 7.6 mg/km and 0.13–0.58 mg/km, respectively, for diesel ( N = 3 ), gasoline direct injection (GDI) ( N = 1 ) and gasoline port-fuel injection (PFI) engine categories ( N = 4 ). For gasoline PFI LDPVs, the instantaneous emission profiles show a strong association of peak BC emissions with cold-start and high-speed aggressive driving. Such impacts lead to considerable BC emission contributions in cold-start periods (e.g., the first 47 s–94 s) over the entire cycle (e.g., 18–76% of the NEDC and 13–36% of the WLTC) and increased BC emission factors by 80–440% under the WLTC compared to the NEDC. For diesel BC emissions, the size distribution exhibits a typical unimodal pattern with one single peak appearing approximately from 120 to 150 nm, which is largely consistent with previous studies. Nevertheless, the average mass ratios of BC to particle mass (PM) range from 0.38 to 0.54 for three diesel samples, representing substantial impacts from both driving and engine conditions. The significant discrepancy between gasoline BC emission factors obtained from tailpipe exhaust versus ambient conditions suggest that more comparative measurements and fine-grained simulations should be designed and implemented to address this discrepancy. [ABSTRACT FROM AUTHOR]

HONO plays a key role in atmospheric chemistry, and while its importance is well-known, the sources of HONO are still not completely understood. As a component of ambient HONO sources, direct emission from vehicles is an area that should be extensively studied. In this study, we determined the HONO emission index for typical gasoline vehicles in the car population of China through a chassis dynamometer with different types of engines (PFI/GDI), starting conditions (cold/warm) and running styles (Beijing cycle). Emission ratios of HONO to nitrogen oxide (NO X ) for the Chinese gasoline cars are determined to be in the range of (0.03–0.42) % and an averaged value is about 0.18%, which are comparable to those reported in the few studies available in Europe, the United States and Japan for gasoline cars while smaller for those of the diesel cars. The atmospheric impact of the direct HONO emission from gasoline cars was analyzed for a typical urban site in Beijing, significant contributions of the direct emission toward the HONO budget were found during morning rush hours or twilight conditions to be 8–12%. [ABSTRACT FROM AUTHOR]

On-road exhaust emissions of a Euro 5 factory bi-fuel CNG/gasoline light-duty vehicle equipped with the TWC were assessed considering the Real Driving Emissions (RDE) guidelines. The vehicle was equipped with a Portable Emission Measurement System (PEMS) that enabled the measurement of THC, CO, NO x , CO 2, and CH 4 . With respect to the characteristics of the vehicle, the appropriate Worldwide Harmonized Light-Duty Vehicle Test Cycles (WLTC) were selected and based on the requirements of the RDE legislation a suitable route was conceived. In addition to the moderate RDE-based route, an extended RDE-based route was also determined. The vehicle was driven along each defined route twice, once with each individual fuel option and with a fully warm vehicle. RDE routes feature a multitude of new driving patterns that are significantly different to those encountered in the NEDC. However, as these driving patterns can greatly influence the cumulative emissions an insight in to local time trace phenomena is crucial to understand, reason and to possibly reduce the cumulative emissions. Original contributions of this paper comprise analyses of the RDE-LDV local time resolved driving emissions phenomena of a CNG-powered vehicle that are benchmarked against the ones measured under the use of gasoline in the same vehicle and under similar operating conditions to reason emission trends through driving patterns and powertrain parameters and exposing the strong cold-start independent interference of CO and N 2 O infrared absorption bands in the non-dispersive infrared (NDIR) analyzer. The paper provides experimental evidence on this interference, which significantly influences on the readings of CO emissions. The paper further provides hypotheses why CO and N 2 O interference is more pronounced when using CNG in LDVs and supports these hypotheses by PEMS tests. The study reveals that the vehicle's NO x real-world emission values of both conceived RDE-based routes when using both fuels are within Euro 5 and type-approval limits. Additionally, the THC and the NMHC emissions of both RDE-based routes using both fuels are within the Euro 5 limits indicating reasonable CH 4 emissions. Notable increases above the type-approval and Euro 5 limits appeared in the CO emissions profile when using gasoline, while the CO 2 emissions profile expectedly also exceeded the type-approval specifications. [ABSTRACT FROM AUTHOR]

The purpose of this study is to investigate possible improvements in ICEVs by implementing fuzzy logic-based parallel hard-type power hybrid systems. Two types of conventional ICEVs (gasoline and diesel) and two types of HEVs (gasoline-electric, diesel electric) were generated using vehicle and powertrain simulation tools and a Matlab-Simulink application programming interface. For gasoline and gasoline-electric HEV vehicles, the prediction accuracy for four types of LDV models was validated by conducting comparative analysis with the chassis dynamometer and OBD test data. The predicted results show strong correlation with the test data. The operating points of internal combustion engines and electric motors are well controlled in the high efficiency region and battery SOC was well controlled within ± 1.6%. However, for diesel vehicles, we generated virtual diesel-electric HEV vehicle because there is no available vehicles with similar engine and vehicle specifications with ICE vehicle. Using a fuzzy logic-based parallel hybrid system in conventional ICEVs demonstrated that HEVs showed superior performance in terms of fuel consumption and CO 2 emission in most driving modes. [ABSTRACT FROM AUTHOR]

Understanding the fuel economy of vehicles in actual use has important implications for fuel economy, greenhouse gas emission and consumer information policies. This study explores how fuel economy varies with intensity of daily vehicle use, cumulative mileage, and ambient temperature. Using a unique longitudinal database, we quantify variations in fuel economy (miles per gallon or MPG) over time for the same vehicle. The database consists of more than 600,000 odometer and fuel purchase records, obtained from the “My MPG” section of the http://fueleconom y.g ov website. Over 10,000 drivers reported their fuel purchases and vehicle usage, with an average of 36 fill-ups per vehicle. Multilevel models are used to analyze and compare relationships for conventional gasoline and hybrid vehicles. For gasoline vehicles, within-vehicle variation accounts for 23% total variation of fuel economy and 77% is between-vehicle variation. For hybrids, the equivalent proportions are 19% and 81%. On-road fuel economy increases nonlinearly with cumulative mileage, with nearly all of the increase occurring within the first few thousand miles. The estimated trend for hybrid vehicles is very different from that of conventional gasoline vehicles. Hybrids were found to have higher daily miles of use than conventional gasoline vehicles. Cold temperatures appear to have a greater effect on the fuel economy of hybrids than conventional gasoline vehicles. [ABSTRACT FROM AUTHOR]

Highly-loaded and well-dispersed Fe 5 C 2 nanoparticles within ordered mesoporous carbon CMK-3 (Fe 5 C 2 @CMK-3) were prepared via a simple melt infiltration method. They were successfully applied to high-temperature Fischer-Tropsch synthesis, and showed high CO conversion (91%) and activity (5.1 × 10 −4 mol co g Fe −1 s −1 ) as well as good selectivity (38 wt%) for gasoline-range hydrocarbons (C 5 –C 12 ). The catalytic property of Fe 5 C 2 @CMK-3 was newly interpreted, based on theoretical data obtained by computational simulations. [ABSTRACT FROM AUTHOR]

Greenhouse experiments were carried out to determine the phytotoxic effects on the plant Ludwigia octovalvis in order to assess its applicability for phytoremediation gasoline-contaminated soils. Using plants to degrade hydrocarbons is a challenging task. In this study, different spiked concentrations of hydrocarbons in soil (1, 2, and 3 g/kg) were tested. The results showed that the mean efficiency of total petroleum hydrocarbon (TPH) removal over a 72-day culture period was rather high. The maximum removal of 79.8 % occurred for the 2 g/kg concentration, while the removal rate by the corresponding unplanted controls was only (48.6 %). The impact of gasoline on plants included visual symptoms of stress, yellowing, growth reduction, and perturbations in the developmental parameters. The dry weight and wet weight of the plant slightly increased upon exposure to gasoline until day 42. Scanning electron microscopy (SEM) indicated change to the root and stem structure in plant tissue due to the direct attachment with gasoline contaminated compared to the control sample. The population of living microorganisms in the contaminated soil was found to be able to adapt to different gasoline concentrations. The results showed that L. octovalvis and rhizobacteria in gasoline-contaminated soil have the potential to degrade organic pollutants. [ABSTRACT FROM AUTHOR]

The effect of fuel ethanol content (10, 85 and 100 %) on primary emissions and on subsequent secondary aerosol formation was investigated for a Euro 5 flex-fuel gasoline vehicle. Emissions were characterized during a New European Driving Cycle (NEDC) using a comprehensive setup of high time-resolution instruments. A detailed chemical composition of the exhaust particulate matter (PM) was studied using a soot particle aerosol mass spectrometer (SPAMS), and secondary aerosol formation was studied using a potential aerosol mass (PAM) chamber. For the primary gaseous compounds, an increase in total hydrocarbon emissions and a decrease in aromatic BTEX (benzene, toluene, ethylbenzene and xylenes) compounds was observed when the amount of ethanol in the fuel increased. In regard to particles, the largest primary particulate matter concentrations and potential for secondary particle formation was measured for the E10 fuel (10% ethanol). As the ethanol content of the fuel increased, a significant decrease in the average primary particulate matter concentrations over the NEDC was found. The PM emissions were 0.45, 0.25 and 0.15 mg m-3 for E10, E85 and E100, respectively. Similarly, a clear decrease in secondary aerosol formation potential was observed with a larger contribution of ethanol in the fuel. The secondary-toprimary PM ratios were 13.4 and 1.5 for E10 and E85, respectively. For E100, a slight decrease in PM mass was observed after the PAM chamber, indicating that the PM produced by secondary aerosol formation was less than the PM lost through wall losses or the degradation of the primary organic aerosol (POA) in the chamber. For all fuel blends, the formed secondary aerosol consisted mostly of organic compounds. For E10, the contribution of organic compounds containing oxygen increased from 35 %, measured for primary organics, to 62% after the PAM chamber. For E85, the contribution of organic compounds containing oxygen increased from 42% (primary) to 57% (after the PAM chamber), whereas for E100 the amount of oxidized organics remained the same (approximately 62 %) with the PAM chamber when compared to the primary emissions. [ABSTRACT FROM AUTHOR]

Purpose: Bioethanol is not currently produced in Chile. However, mixtures of bioethanol-gasoline at 2 and 5 % have been authorized. The production and use of the bioethanol-gasoline blend 'E5' has been assessed using life cycle assessment (LCA) with the aim to compare the environmental profiles of bioethanol produced from Eucalyptus globulus with gasoline in Chile and to determine the potential of this biofuel-replacing gasoline in the transport sector. Methods: The standard framework of LCA described by ISO was selected to assess the ecological burdens derived from the biofuel production using the SimaPro v7.8 software. The system boundaries included eucalyptus cultivation, bioethanol production, E5 blend production, and final use of E5. The inventory data for Eucalyptus cultivation were previously collected through surveys with forest managers. Inventory data for bioethanol production were obtained by process simulation models using Aspen Plus v7.1, and for non-simulated or modeled information, secondary information (scientific articles and reports) was used. Conventional gasoline, produced and used in Chile, was used as base scenario for comparison with E5 scenario. Results and discussion: The environmental results showed reduction of the environmental impacts in most of the assessed categories when E5 blend is assessed and compared with gasoline. Reduction was evident for climate change, photochemical oxidation formation, terrestrial acidification, marine eutrophication, terrestrial ecotoxicity, marine ecotoxicity, depletion of water, and fossil resources. However, there was an increase in other impact categories, such as ozone layer depletion, human toxicity, terrestrial ecotoxicity, and marine eutrophication. The hotspots for E5 blend were the blending production and the combustion in the engine, whereas in the production process, the electricity production was the major contributor to most of the impact categories. When increasing the bioethanol content from E5 to E10 blend, the environmental impact increases in most of the evaluated categories except in the CC, WD, and FD categories. However, compared with other studies related to wood-based E10, the values for the environmental impacts obtained were lower than the reported. Conclusions: The use of E5 blend can help to reduce the environmental impact in 8 of the 12 categories analyzed. Environmental impacts obtained are lower compared with other studies reported for E10 blend production from wood resources. [ABSTRACT FROM AUTHOR]

Volatile organic compound (VOCs) emissions from sources often need to be compressed or “lumped” into species classes for use in emissions inventories intended for air quality modeling. This needs to be done to ensure computational efficiency. The lumped profiles are usually reported for one value of ambient temperature. However, temperature-specific detailed profiles have been constructed in the recent past - the current study investigates how the lumping of species from those profiles into different atmospheric chemistry mechanisms is affected by temperature, considering three temperatures (−18 °C, −7 °C and 24 °C). The mechanisms considered differed on the assumptions used for lumping: CB05 (carbon bond type), SAPRC (ozone formation potential) and RACM2 (molecular surrogate and reactivity weighting). In this space, four sub-mechanisms for SAPRC were considered. Scaling factors were developed for each lumped model species and mechanism in terms of moles of lumped species per unit mass. Species which showed a direct one-to-one mapping (SAPRC/RACM2) reported scaling factors that were unchanged across mechanisms. However, CB05 showed different trends since one compound often is mapped onto multiple model species, out of which the paraffinic double bond (PAR) is predominant. Temperature-dependent parameterizations for emission factors pertaining to each lumped species class and mechanism were developed as part of the study. Here, the same kind of model species showed varying lumping parameters across the different mechanisms. These differences could be attributed to differing approaches in lumping. The scaling factors and temperature-dependent parameterizations could be used to update emissions inventories such as MOVES or SMOKE for use in chemical transport modeling. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are contaminants widespread in the environment and vehicular emissions have long been recognized as the most important anthropogenic sources of PAHs in urban air Polycyclic aromatic hydrocarbons (PAHs) emitted in the exhaust gases of diesel and petrol engines using different fuels were quantified. Size fractionated chemical analysis of particles in vehicle emissions were carried out by sampling with an electrical low pressure multi-stage impactor ELPI. The mean concentrations of total PAHs adsorbed onto the particulate matter in the rage of 0.03-0.25 μm emitted from the exhaust gases were 48.3, 128.2 and 83.0 ng·m-3, respectively from three kinds of diesel fuels. Results indicated that PAHs present in the last two fraction (0.17-0.25 μm) have the highest contribution in the total content of these compounds. In the collected fractions of particulate matter emitted in gasoline engine exhaust 12 compounds were identified in the 0.25 μm fraction and 9 PAHs in the 0.17 μm fraction. [ABSTRACT FROM AUTHOR]

Life cycle assessments (LCAs) have become a common tool for measuring the environmental performance of various products and processes. This study reviewed the life cycle of lignocellulosic biomass feedstock-based (pine, eucalyptus, and switchgrass) ethanol biofuels and compared the results to gasoline. Uncertainty analysis of the cradle-to-wheel results was conducted using a pedigree matrix method to address uncertainty of life cycle inventory items. A tool called stochastic multi-attribute analysis for life cycle impact assessment (SMAA-LCIA) was used to interpret the results generated from the LCA. The normalized results showed that gasoline had high environmental impacts in categories such as carcinogenics and global warming, followed by switchgrass. But the use of a single-score metric indicated that all bio-based feedstocks had similar environmental performance, all significantly better than gasoline. The SMAA-LCIA results showed that when all impacts were weighted equally, the preference from highest to lowest was for loblolly pine, eucalyptus, gasoline, and switchgrass. This rank order switched when differing weighting schemes of Producer, User, and LCA Expert were used. Overall, this method highlights the trade-offs associated with the selection of different feedstocks and improves the comparison of overall results amongst fuel sources, which can then be more clearly presented to a decision-maker. © 2016 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

Adaptation planning of energy systems to climatic change is highly complicated due to complex interactions among various adaptation responses, and among energy-related activities. These complexities may be further compounded as a result of the presence of interval-format uncertainty associated with energy systems management and climate change adaptation responses. This study is to develop an inexact community-scale energy system adaptation model (ICEAM) for supporting adaptation planning of community-scale energy systems under uncertainty. The objective entails the tasks including: (1) investigation of adaptation responses of the energy sector to climate change, (2) uncertainty analysis, and (3) development of ICEAM and apply it to the City of Waterloo, Canada. The results indicate that, to adapt to a changing climate by the City of Waterloo, more electricity and gasoline and less natural gas would be imported. The results also suggest that the ICEAM has an advantage of the planning adaptation response of energy activities, but also addressing the uncertainty existing in energy management systems and regional climate prediction. [ABSTRACT FROM AUTHOR]

The article provides information on the consumption and production of greenhouse gas emission for Nova Scotia and its associate trade flows, during the production process of final good and services. Topics discussed includes Investment in greenhouse gas emission, Trade flow from Nova Scotia to Ontario and Motor Gasoline.

Research shows that for every gallon of gasoline burnt, 12.7kg of CO 2 is released. Fuel economy improvement is almost linear with a reduction in weight of a car. Therefore, reducing vehicle weight results in less fuel consumption and a decrease in CO 2 emission which in turn has an effect on global warming. Car manufacturers are facing increasingly stringent CO 2 emission standard. In this project, an investigation was carried out on vehicle suspension system (VSS) by employing Finite Element Analysis (FEA) to analyze the fatigue life, von misses stress, factor of safety and stability of the suspension system and how the weight and size can be reduced. Solidworks14 ® was employed to analyze different materials used in the design and development of VSS; comparison amongst the various materials used was carried out to inform that there can be reduction in the size and weight of the four suspension system by using Titanium Ti-13V-11Cr-3Al Treated, which will drastically reduce the weight of the car and give better result of strength and durability, ultimately reducing CO 2 emission and its negative effect on the climate. This innovative design can be introduced as a reference for the automotive industry. [ABSTRACT FROM AUTHOR]

Gasoline direct injection (GDI) engines are increasingly prevalent in the global vehicle fleet. Particulate matter emissions from GDI engines are elevated compared to conventional gasoline engines. The pulmonary effects of these higher particulate emissions are unclear. This study investigated the pulmonary responses induced by GDI engine exhaust using an ex vivo model. The physiochemical properties of GDI engine exhaust were assessed. Precision cut lung slices were prepared using Balb/c mice to evaluate the pulmonary response induced by one-hour exposure to engine-out exhaust from a laboratory GDI engine operated at conditions equivalent to vehicle highway cruise conditions. Lung slices were exposed at an air-liquid interface using an electrostatic aerosol in vitro exposure system. Particulate and gaseous exhaust was fractionated to contrast mRNA production related to polycyclic aromatic hydrocarbon (PAH) metabolism and oxidative stress. Exposure to GDI engine exhaust upregulated genes involved in PAH metabolism, including Cyp1a1 (2.71, SE = 0.22), and Cyp1b1 (3.24, SE = 0.12) compared to HEPA filtered air ( p < 0.05). GDI engine exhaust further increased Cyp1b1 expression compared to filtered GDI engine exhaust ( i.e. , gas fraction only), suggesting this response was associated with the particulate fraction. Exhaust particulate was dominated by high molecular weight PAHs. Hmox1 , an oxidative stress marker, exhibited increased expression after exposure to GDI (1.63, SE = 0.03) and filtered GDI (1.55, SE = 0.04) engine exhaust compared to HEPA filtered air ( p < 0.05), likely attributable to a combination of the gas and particulate fractions. Exposure to GDI engine exhaust contributes to upregulation of genes related to the metabolism of PAHs and oxidative stress. [ABSTRACT FROM AUTHOR]

Impacts of gasoline pollution on the soil environment, bacterial and weed population dynamics were investigated for several months. Known amounts of gasoline were added to 2kg of soil. In the first experiment the soil was immediately sampled for microbial load and presence of weeds. In the second experiment the soil was sampled after three months for microbial load and presence of weeds. In the third experiment the soil was sampled after 6 months for microbial load and presence of weeds. The soil was sampled weekly for twelve weeks in each of the three experiments. Weeds that grew on the soil were noted and identified. Bacteria isolated were identified using 16S rRNA sequencing. The identified bacteria include Bacillus spp., Pseudomonas sp, and Ochrobactrum sp. The bacteria were further tested for their ability to grow on gasoline as the only source of carbon and their growth measured by optical density, change in pH and total viable counts. Results showed ability to utilize gasoline as the only source of carbon and energy. The emulsification activities of the isolates were greater than 50% indicating higher potential to biodegrade gasoline. It is concluded that it is possible to isolate oil degrading bacteria capable of in situ biodegradation from the Niger Delta region of Nigeria. It is suggested that the identified weeds have some roles to play in the biodegradation of gasoline by bacteria. [ABSTRACT FROM AUTHOR]

During gasoline spills complex mixtures of toxic volatile organic compounds (VOCs) are released to terrestrial environments. Gasoline VOCs exert baseline toxicity (narcosis) and may thus broadly affect soil biota. We assessed the functional resilience (i.e. resistance and recovery of microbial functions) in soil microbial communities transiently exposed to gasoline vapors by passive dosing via headspace for 40 days followed by a recovery phase of 84 days. Chemical exposure was characterized with GC-MS, whereas microbial activity was monitored as soil respiration (CO 2 release) and soil bacterial growth ([ 3 H]leucine incorporation). Microbial activity was strongly stimulated and inhibited at low and high exposure levels, respectively. Microbial growth efficiency decreased with increasing exposure, but rebounded during the recovery phase for low-dose treatments. Although benzene, toluene, ethylbenzene and xylene (BTEX) concentrations decreased by 83–97% during the recovery phase, microbial activity in high-dose treatments did not recover and numbers of viable bacteria were 3–4 orders of magnitude lower than in control soil. Re-inoculation with active soil microorganisms failed to restore microbial activity indicating residual soil toxicity, which could not be attributed to BTEX, but rather to mixture toxicity of more persistent gasoline constituents or degradation products. Our results indicate a limited potential for functional recovery of soil microbial communities after transient exposure to high, but environmentally relevant, levels of gasoline VOCs which therefore may compromise ecosystem services provided by microorganisms even after extensive soil VOC dissipation. [ABSTRACT FROM AUTHOR]

The operation of modern vehicles requires the introduction of package of fuel additives to ensure the required level of operating characteristics, some of which cannot be achieved by current oil refining methods. The use of additives allows flexibility of impact on the properties of the fuel at minimal cost, increasing the efficiency and environmental safety of vehicles. Among the wide assortment of additives available on the world market, many are surfactants. It has been shown that the introduction of some surfactants into gasoline concurrently reduces losses from gasoline evaporation, improves the mixture formation during injection of gasoline into the engine and improves detergent and anticorrosive properties. The surfactant gasoline additive that provides significant improvement in the quality of gasoline used and environmental and operating characteristics of vehicles has been developed and thoroughly investigated. The results of studies confirming the efficiency of the gasoline additive application are herein presented. [ABSTRACT FROM AUTHOR]

Motorcycles are the third most common means of transportation in the megacity of Tehran. Hence, measurements of emission factors are essential for Tehran motorcycle fleets. In this study, 60 carburetor motorcycles of various mileages and engine displacement volumes were tested in a chassis dynamometer laboratory according to cold start Euro-3 emissions certification test procedures. For almost all of the tested samples, the average carbon monoxide (CO) emission factors were about seven times higher than the limits for Euro-3 certification. No motorcycle fell within the Euro-3 certification limit on CO emissions. 125 cc engine displacement volume motorcycles, which are dominant in Tehran, have the most total unburned hydrocarbons and CO emission rates, and they have less nitrous oxides (NO X ) emission rates and fuel consumption compared to those of larger engine volume motorcycles. Calculation of fuel-based emission factors and moles of combustion products shows that about 40% of fuel consumed by 125 cc engine volume motorcycles burns to incomplete combustion products. This proportion is lower for larger engine volume motorcycles. Approximation of relative air–fuel ratio results shows very rich combustion in selected motorcycles. Using a carburetor fuel supply system, low engine compression ratio, aging, and no catalyst could be reasons for high emission rates. These reasons could possibly result in high ultrafine particles emission rates from motorcycles. Comparison of total motorcycle pollutant emissions to that of passenger cars from previous studies in Tehran shows that motorcycles contribute to pollutant much higher than their contribution to the total fleet or total travels. [ABSTRACT FROM AUTHOR]

Refined fuels have considerable share of pollution of marine ecosystems. Gasoline is one of the most consumed fuel worldwide, but its effects on marine benthic primary producers are poorly investigated. In this study, Ulva lactuca was chosen as a biological model due to its cosmopolitan nature and tolerance to high levels and wide range of xenobiotics and our goal was to evaluate the effects of gasoline on ultrastructure and metabolism of that seaweed. The experimental design consisted of in vitro exposure of U. lactuca to four concentrations of gasoline (0.001%, 0.01%, 0.1%, and 1.0%, v/v) over 30 min, 1 h, 12 h, and 24 h, followed by cytochemical, SEM, and biochemical analysis. Increase in the number of cytoplasmic granules, loss of cell turgor, cytoplasmic shrinkage, and alterations in the mucilage were some of the ultrastructural alterations observed in thalli exposed to gasoline. Decrease in carotenoid and polyphenol contents, as well as increase of soluble sugars and starch contents were associated with the time of exposure to the xenobiotic. In combination, the results revealed important morphological and biochemical alterations in the phenotype of U . lactuca upon acute exposure to gasoline. This seaweed contain certain metabolites assigned as candidates to biomarkers of the environmental stress investigated and it is thought to be a promise species for usage in coastal ecosystems perturbation monitoring system. In addition, the findings suggest that U . lactuca is able to metabolize gasoline hydrocarbons and use them as energy source, acting as bioremediator of marine waters contaminated by petroleum derivatives. [ABSTRACT FROM AUTHOR]

For the first time, gasoline and diesel range C6–C15 branched alkanes were directly synthesized in a high carbon yield (∼80%) by the self-condensation of acetone and subsequent hydrodeoxygenation over a dual-bed catalyst system. [ABSTRACT FROM AUTHOR]

Since the 1990s, questions have arisen as to whether the release of ethanol-blended fuel will inhibit natural attenuation of other gasoline constituents in groundwater. This study evaluated the hypothesis that ethanol affects hydrocarbon attenuation and whether the use of ethanol-blended fuel alters the applicability of monitored natural attenuation ( MNA) as an approach for managing risks at fuel-release sites. Groundwater data from California's GeoTracker database were used to compare attenuation of benzene, toluene, methyl tert-butyl ether ( MTBE), and tert-butyl alcohol ( TBA) at sites with and without detections of ethanol. Excel-based tools were developed to conduct attenuation evaluations on thousands of wells simultaneously. Ethanol was detected at least once in 4.5% of the wells and 0.6% of the samples of which it was analyzed. The distribution of Mann-Kendall concentration trend analysis results and first-order attenuation rates were essentially the same at sites with or without ethanol detections. Median plume lengths were shorter at sites where ethanol had not been detected compared to sites where ethanol was detected (36 vs. 43 m for benzene; 36 vs. 42 m for toluene; 43 vs. 52 m for MTBE; and 44 vs. 59 m for TBA). However, the distribution of plume lengths was similar irrespective of ethanol concentrations, suggesting other factors may influence plume elongation. Finally, while anaerobic ethanol degradation can result in methane generation, the distributions of methane concentrations were the same at sites with and without ethanol detections. These results suggest that the use of ethanol-blended fuel should not limit the application of MNA at most biodegrading fuel-release sites. [ABSTRACT FROM AUTHOR]

Hydrogen cyanide (HCN) is considered a marker for biomass burning emissions and is a component of vehicle exhaust. Despite its potential health impacts, vehicular HCN emissions estimates and their contribution to regional budgets are highly uncertain. In the current study, Proton Transfer Reaction-Time of Flight-Mass Spectrometry (PTR-ToF-MS) was used to measure HCN emission factors from the exhaust of individual diesel, biodiesel and gasoline vehicles. Laboratory emissions data as a function of fuel type and driving mode were combined with ambient measurement data and model predictions. The results indicate that gasoline vehicles have the highest emissions of HCN (relative to diesel fuel) and that biodiesel fuel has the potential to significantly reduce HCN emissions even at realistic 5% blend levels. The data further demonstrate that gasoline direct injection (GDI) engines emit more HCN than their port fuel injection (PFI) counterparts, suggesting that the expected full transition of vehicle fleets to GDI will increase HCN emissions. Ambient measurements of HCN in a traffic dominated area of Toronto, Canada were strongly correlated to vehicle emission markers and consistent with regional air quality model predictions of ambient air HCN, indicating that vehicle emissions of HCN are the dominant source of exposure in urban areas. The results further indicate that additional work is required to quantify HCN emissions from the modern vehicle fleet, particularly in light of continuously changing engine, fuel and after-treatment technologies. [ABSTRACT FROM AUTHOR]

Benzene is a known carcinogen, and is desired to be removed from the gasoline additive for environmental reason. A benzene removal process from the additive, reformate of catalytic reformers, is proposed utilizing an extended DWC (divided wall column). The DWC reduces the processing load of the whole process especially in extractor, which employs high boiling point solvent requiring large amount of energy and costly utility. In this study the design of the proposed process is addressed along with the evaluation of energy saving, economics and thermodynamic efficiency. The evaluation results indicate the heating duty reduction of 56.8% from the proposed process over the conventional process and 64.6% reduction of cooling duty. The economics reveals the 26% reduction of investment and 56% reduction of utility cost from the proposed process. However, no significant improvement of thermodynamic efficiency is yielded. [ABSTRACT FROM AUTHOR]

The adverse health effects of environmental exposure to gaseous and particulate components of vehicular emissions are a major concern among urban populations. A link has been established between respiratory exposure to vehicular emissions and the development of cardiovascular disease (CVD), but the mechanisms driving this interaction remain unknown. Chronic inhalation exposure to mixed vehicle emissions has been linked to CVD in animal models. This study evaluated the temporal effects of acute exposure to mixed vehicle emissions (MVE; mixed gasoline and diesel emissions) on potentially active metabolites in the serum of exposed mice. C57Bl/6 mice were exposed to a single 6-hour exposure to filtered air (FA) or MVE (100 or 300 μg/m3) by whole body inhalation. Immediately after and 18 hours after the end of the exposure period, animals were sacrificed for serum and tissue collection. Serum was analyzed for metabolites that were differentially present between treatment groups and time points. Changes in metabolite levels suggestive of increased oxidative stress (oxidized glutathione, cysteine disulfide, taurine), lipid peroxidation (13-HODE, 9-HODE), energy metabolism (lactate, glycerate, branched chain amino acid catabolites, butrylcarnitine, fatty acids), and inflammation (DiHOME, palmitoyl ethanolamide) were observed immediately after the end of exposure in the serum of animals exposed to MVE relative to those exposed to FA. By 18 hours post exposure, serum metabolite differences between animals exposed to MVE versus those exposed to FA were less pronounced. These findings highlight complex metabolomics alterations in the circulation following inhalation exposure to a common source of combustion emissions. [ABSTRACT FROM AUTHOR]

Four field campaigns were conducted between February 2014 and January 2015 to measure emissions from light-duty gasoline direct injection (GDI) vehicles (2013 Ford Focus) in an urban near-road environment in Toronto, Canada. Measurements of CO2, CO, NOx, black carbon (BC), benzene, toluene, ethylbenzene-xylenes (BTEX), and size-resolved particle number (PN) were recorded 15 m from the roadway and converted to fuel-based emission factors (EFs). Other than for NOx and CO, the GDI engine had elevated emissions compared to the Toronto fleet, with BC EFs in the 73rd percentile, BTEX EFs in the 80-90th percentile, and PN EFs in the 75th percentile during wintertime measurements. Additionally, for three campaigns, a second platform for measuring PN and CO2 was placed 1.5-3 m from the roadway to quantify changes in PN with distance from point of emission. GDI vehicle PN EFs were found to increase by up to 240% with increasing distance from the roadway, predominantly due to an increasing fraction of sub-40 nm particles. PN and BC EFs from the same engine technology were also measured in the laboratory. BC EFs agreed within 20% between the laboratory and real-world measurements; however, laboratory PN EFs were an order of magnitude lower due to exhaust conditioning. [ABSTRACT FROM AUTHOR]

This study is the third in a series of three papers aimed at characterizing the VOC emissions of vehicles in Beijing. In this study, 30 light-duty vehicles fueled with gasoline were evaluated using a portable emission measurement system (PEMS) as they were driven on a predesigned, fixed test route. All of the tested vehicles were rented from private vehicle owners and spanned regulatory compliance guidelines ranging from Pre-China I to China IV. Alkanes, alkenes, aromatics and some additional species in the exhaust were collected in Tedlar bags and analyzed using gas chromatography/mass spectrometry (GC–MS). Carbonyls were collected on 2,4-dinitrophenyhydrazine (DNPH) cartridges and analyzed using high-performance liquid chromatography (HPLC). Overall, 74 VOC species were detected from the tested vehicles, including 22 alkanes, 6 alkenes, 1 alkyne, 16 aromatics, 3 cyclanes, 10 halohydrocarbons, 12 carbonyls and 4 other compounds. Alkanes, aromatics and carbonyls were the dominant VOCs with weight percentages of approximately 36.4%, 33.1% and 17.4%, respectively. The average VOC emission factors and standard deviations of the Pre-China I, China I, China II, China III and China IV vehicles were 469.3 ± 200.1, 80.7 ± 46.1, 56.8 ± 37.4, 25.6 ± 11.7 and 14.9 ± 8.2 mg/km, respectively, which indicated that the VOC emissions significantly decreased under stricter vehicular emission standards. Driving cycles also influenced the VOC emissions from the tested vehicles. The average VOC emission factors based on the travel distances of the tested vehicles under urban driving cycles were greater than those under highway driving cycles. In addition, we calculated the ozone formation potential (OFP) using the maximum incremental reactivity (MIR) method. The results of this study will be helpful for understanding the true emission levels of light-duty gasoline vehicles and will provide information for controlling VOC emissions from vehicles in Beijing, China. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the contribution of the main emission sources of PAHs associated with PM 2.5 , in an urban area of the Rio Grande do Sul state. Source apportionment was conducted using both the US EPA Positive Matrix Factorization (PMF) model and the Chemical Mass Balance (CMB) model. The two models were compared to analyze the source contributions similarities and differences, their advantages and disadvantages. PM 2.5 samples were collected continuously over 24 h using a stacked filter unit at 3 sampling sites of the urban area of the Rio Grande do Sul state every 15 days between 2006 and 2008. Both models identified the main emission sources of PAHs in PM 2.5 : vehicle fleet (diesel and gasoline), coal combustion, wood burning, and dust. Results indicated similar source contribution amongst the sampling sites, as expected because of the proximity amongst the sampling sites, which are under the influence of the same pollutants emitting sources. Moreover, differences were observed in obtained sources contributions for the same data set of each sampling site. The PMF model attributed a slightly greater amount of PAHs to the gasoline and diesel sources, while diesel contributed more in the CMB results. The results were comparable with previous works of the region and in accordance with the characteristics of the study area. Comparison between these receptor models, which contain different physical constraints, is important for understanding better PAH emissions sources in order to reduce air pollution. [ABSTRACT FROM AUTHOR]

In a port fuel injection engine, optimized kinetic process technology is implemented to realize homogenous charge compression ignition (HCCI) combustion with dual-fuel injection. The effects of intake air temperature on HCCI combustion and emissions are investigated. The results show that dual-fuel control prolongs HCCI combustion duration and improves combustion stability. Dual-fuel HCCI combustion needs lower intake air temperature than gasoline HCCI combustion, which reduces the requirements on heat management system. As intake air temperature decreases, air charge increases and maximum pressure rising rate decreases. When intake air temperature is about 55i°C, HCCI combustion becomes worse and misfire happens. In fixed dual fuel content condition, HC and CO emission decreases as intake air temperature increases. The combination of dual-fuel injection and intake air temperature control can expand operation range of HCCI combustion. [ABSTRACT FROM AUTHOR]

The transport sector -- road transport, in particular -- accounts for more than half of world oil consumption. In the future, the transport sector's share of oil consumption will grow even more, primarily due to the increasing use of motor vehicles in developing and emerging countries. Road freight transport will also take on greater significance. And overall, gasoline -- and, increasingly, diesel -- will continue to dominate the fuel mix. A trend reversal in which road transport moves toward a more intensive use of alternative fuels such as liquefied petroleum gas (LPG) and natural gas, and alternative drive systems such as hybrid cars (HEVs) and battery electric vehicles (BEVs), still cannot be observed -- despite government support. Given that gasoline and diesel will also be dominant in the future, additional efforts should be made to reduce CO2 emissions and improve the environmental friendliness of motor vehicle traffic. Given the deleterious environmental effects of diesel fuel, its preferential tax treatment should be abolished. [ABSTRACT FROM AUTHOR]

Recent years have shown an increasing interest in ethanol blending to gasoline fuel, as well as a rapid implementation of this kind of biofuels in countries like Colombia. Taking into account the lack of studies about performance and emissions characteristics for the local engines, and the fact that new biofuels policies are emerging using studies made for non-local conditions, a study is proposed in order to verify the real changes in those characteristics into the Colombian conditions. This article presents a performance and emission analysis when different independent variables act on two engines working with gasoline-ethanol blends up to 30 % of the latter. A set of dependent variables are introduced in order to verify the real statistical influence of independent variables. Results confirm trends reported by other authors; nevertheless, these tendencies are not always statistical representative, like in the case of ethanol concentration influence on combustion duration. [ABSTRACT FROM AUTHOR]

The Worldwide Harmonized Light Duty Test Procedure (WLTP), recently issued as GTR15 by UNECE-WP29, is designed to check the pollutant emission compliance of Light Duty Vehicles (LDVs) around the world and to establish the reference vehicle fuel consumption and CO2 performance. In the course of the development of WLTP, the Joint Research Center (JRC) of the European Commission has tested gaseous emissions of twenty-one Euro 4-6 gasoline and diesel vehicles, on both the current European type approval test procedure (NEDC) and the progressive versions of the WLTP. The results, which should be regarded just as an initial and qualitative indication of the trends, demonstrated minimal average differences between CO2 emissions over the NEDC and WLTP. On the other hand, CO2 emissions measured at JRC on the NEDC were on average 9% higher than the respective type approval values, therefore suggesting that for the tested vehicles, CO2 emissions over WLTP were almost 10% higher than the respective NEDC type approval values. That difference is likely to increase with application of the full WLTP test procedure. Measured THC emissions from most vehicles stayed below the legal emission limits and in general were lower under the WLTP compared to NEDC. Moving from NEDC to WLTP did not have much impact on NOx from gasoline vehicles and CO from diesel vehicles. On the contrary, NOx from diesel vehicles and CO from low-powered gasoline vehicles were significantly higher over the more dynamic WLTP and in several cases exceeded the emission limits. Results from this study can be considered indicative of emission patterns of modern technology vehicles and useful to both policy makers and vehicle manufacturers in developing future emission policy/technology strategies. [ABSTRACT FROM AUTHOR]

Purpose: In order to understand the environmental outcomes associated with the life cycle of a product, to compare these outcomes across products, or to design more sustainable supply chains, it is often desirable to estimate results for a reference supply chain representative of the conditions for a sector in a specific region. This paper, by examining ethanol and gasoline production processes, explains how choices made in the calculation of sector-representative emission factors can have a significant effect on the emission estimates used in life cycle assessments. Methods: This study estimates reference emission factors for United States dry-grind corn ethanol production and gasoline production processes suitable for use in baseline life cycle assessment unit processes. Based on facility-specific emissions and activity rates from the United States National Emissions Inventory, the Energy Information Administration, and an ethanol industry trade publication, the average emissions per unit energy content of fuel are computed using three different approaches. The Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts (TRACI) characterization factors are used to estimate impact potentials for six environmental and three human health categories. Sector-specific direct emissions and impact potentials are compared across the three approaches and between the two sectors. The system boundary for this analysis is limited to the fuel production stage of these transportation fuel lifecycles. Results and discussion: Findings from this work suggest that average emission factors based on total emissions and total production may significantly under estimate actual process emissions due to reporting thresholds and otherwise unreported emissions. Conclusions: Because of the potential for unreported emissions in regional inventories, it is more appropriate to estimate sector reference emission factors based on matched sets of facility or process level emissions and activity rates than to use aggregated totals. This study demonstrates a method which can be used for inventory development in cases where multiple facilities producing the same product are involved. [ABSTRACT FROM AUTHOR]