Global Vehicle Fleet Research Articles

ელექტრული ავტოტრანსპორტის განვითარების ტენდენციები მსოფლიოსა და საქართველოში

The intensive growth of the global vehicle fleet and environmental pollution caused by harmful emissions from vehicles have become one of the global environmental problems. In addition to that, oil prices are continuing to rise. A radical way to solve the problems of environmental safety and fuel efficiency of cars is to use electric current as an energy source in a car. The complete replacement of the internal combustion engine with an electric motor – in electric cars or a combination of the two – in hybrid cars completely eliminates or significantly reduces fuel consumption and harmful emissions. Electric cars are replacing cars with internal combustion engines from all dynamically developing world markets. Replacing cars with internal combustion engines with electric ones is especially important for Georgia, where almost 100% of natural gas and oil products are imported and road transport accounts for the largest share of environmental pollution, especially in cities. The country has the potential to create significant additional energy capacity for electric vehicles. Georgia aims to become a regional leader in clean energy consumption – a “green” country and ensure compatibility with the European Union's carbon neutrality goal by 2050, in which electric vehicles play an important role.

Assessing heavy metal contamination in a Brazilian metropolis: a case study with a focus on (bio)indicators.

The continuous expansion of the global vehicle fleet poses a growing threat to environmental quality through heavy metal contamination. In this scenario, monitoring to safeguard public health in urban areas is necessary. Our study involved the collection of 36 street dust and 29 moss samples from roads of a Brazilian metropolis (Recife) with varying traffic intensities as follows: natural reserve (0 vehicles per day), low (< 15,000 vehicles per day), medium (15,000-30,000 vehicles per day), and high (> 30,000 vehicles per day). ICP-AES analysis was performed to determine the concentrations of nine potentially toxic metals (Ba, Cd, Cr, Cu, Mn, Ni, Pb, V, and Zn) to assess the influence of vehicular flow on urban contamination. In the street dust samples, the mean metal concentrations (mg kg-1) exhibited the following order: Ba (503.7) > Mn (303.0) > Zn (144.4) > Cu (95.3) > Cr (56.1) > Pb (34.2) > V (28.7) > Ni (11.3) > Cd (1.5). Conversely, in the moss samples, the metal concentration order was as follows (mg kg-1): Mn (63.8) > Zn (62.5) > Ba (61.0) > Cu (17.7) > Cr (8.0) > V (7.3) > Pb (7.0) > Ni (2.9) > Cd (0.3). Roads with higher traffic volumes exhibited the highest metal enrichments in moss samples for all metals and in dust samples for Cd, Cr, Mn, Ni, and V. However, dust from low-flow roads had higher enrichments for Ba, Cu, and Zn, indicating the influential role of other traffic-related factors in metal deposition. Our findings highlight traffic flow as the predominant source of pollution in urban centers, with both street dust and moss serving as sensitive indicators of metal input attributable to vehicular traffic. These indicators offer valuable insights for urban quality monitoring and pollution control efforts.

Advanced hybrid combustion systems as a part of efforts to achieve carbon neutrality of the vehicles

Global goals, including those of the EU, are focussed on transition to the green, circular and low-carbon economy. The intention within the framework of EU is to achieve the zero level of CO2 emissions for the new cars till the year 2035. An important part of this plan is the agreement between Germany and the European Union that the new vehicles equipped with the internal combustion engines can continue to be sold only in such a case if they will use solely the climate-neutral fuel. Therefore, the future will probably belong to application of the advanced low-temperature technologies in combination with the climate-sustainable fuels (e.g. synthetic fuels, hydrogen). The presented scientific-research work introduces two new low-temperature combustion systems, which were developed and patented at the national level. At the same time, these new combustion systems are tested in cooperation with a reputable automotive producer. It is necessary to emphasize such a positive fact that the obtained results prove relevance of the innovative combustion systems as well as their possible future applicability in the real vehicles as a part of the advanced hybrid drive system.Graphical abstractHighlightsNowadays, the significant efforts are focussed on reduction of gaseous emissions generated by the transport, what is resulting in development of electromobility.CO2 neutrality in the transport sector cannot be reached by the electromobility alone. A potential solution is a combination of the sustainable fuels and advanced low-temperature combustion technologies.These two systems, which are presented in the article, were the subject of experimental research and development.DiscussionWithin the EU, there are strong efforts for a total restriction of internal combustion engines. The German Association of Automotive Industry (VDA) declares that “CO2 neutrality in the transport sector cannot be solved by the electromobility alone”. The official statement of VDA continues: “Even if, in ideal case, we had 15 million electric cars on the roads in 2030, most of the vehicles will still be equipped with combustion engines. Nowadays, 280 million cars are using combustion engines in everyday operation in the EU and there are 1.5 billion of them worldwide. Climate-neutral transport is impossible without new structure of global vehicle fleet and its decarbonisation”. According to VDA, the only solution, how to reduce emission footprint, using the current vehicle fleet, is application of the synthetic fuels. Therefore, still more resources should be invested into research and development of new sustainable fuels.

(Invited) Model-Predictive Design of Low Pt Loaded PEMFC Catalyst Layers

Proton exchange membrane fuel cells (PEMFCs) are a promising means to decarbonize the global vehicle fleet, but commercialization is limited by costly Pt catalysts, among other challenges. PEMFC designs with low Pt loading typically suffer anomalous performance losses. Previous studies have agreed that poor device performance is linked to complex physiochemical processes in the cathode catalyst layer (CL) [1]. More specifically, poor performance with low Pt-loading is attributed to sluggish proton and/or oxygen transport through the nano-thin Nafion ionomer in the CL. Previous studies have also identified that the properties of the Nafion thin films in the CL vary from those previously measured for thicker membranes. However, research has not yet definitively connected CL polymer properties with PEMFC limitations in low Pt-loaded cells, nor found a means to address the limitations for low cost, higher-performance PEMFCs.In this presentation, we will describe efforts to quantify structure-property relationships for thin-film Nafion and incorporate these relationships into PEMFC numerical simulations to identify advantageous PEMFC catalyst layer designs. We model nm-scale transport in thin-film Nafion to develop structure-property relationships for thin-film Nafion, based on in situ neutron reflectometry [2], and conductivity measurements [3] on thin film Nafion. These result in a model that calculates the conductivity as a function of temperature, local water uptake, film thickness, and underlying substrate (Pt or carbon). Incorporating these structure-property models into a continuum-scale PEMFC cathode half-cell model to locally resolve proton conductivity and O2 diffusion improves model fits to PEMFC data with varying Pt loading [4]. The fits provide new insights into the coupling between kinetic, mass transport, and Ohmic losses in low-Pt-loaded PEMFC cathodes and show that Ohmic losses in thin film Nafion play a key limiting role in low-Pt loaded cells. We conclude with a parametric study of PEMFC CL design parameters with low Pt loading. Incorporating multi-scale modelling of Nafion transport processes enhances the predictive model capabilities and unlocks new insights into CL design. We will present a detailed analysis of how best to manage coupled limiting phenomena in PEM fuel cells, and identify functionally graded catalyst layer designs that could significantly improve PEMFC power density with low Pt loading [4]. Weber, A. and Kusoglu, A. Mater. Chem. A. 2014. DOI: 10.1039/c4ta02952fDeCaluwe, S.C. et al. Nano Energy 2018. DOI: 10.1016/j.nanoen.2018.01.008Paul, D.K. et al. Electrochem. Soc. 2014. DOI: 10.1149/2.0571414jesRandall, C.R. and DeCaluwe, S.C., Electrochem. Soc. 2022. DOI: 10.1149/1945-7111/ac8cb4

Syntetické palivá a uhlíková neutralita

The transportation sector is a significant contributor to global greenhouse gas (GHG) emissions, accounting for approximately 14 % of all anthropogenic GHG emissions. Despite the increasing popularity of electric vehicles, internal combustion engines (ICEs) continue to dominate the global vehicle fleet, making it essential to find a way to reduce GHG emissions from this sector. One potential solution is the use of efuels, also known as synthetic fuels, which can significantly reduce GHG emissions from transportation. While there are still several challenges associated with their production and use, the benefits of efuels make them a solution worth pursuing. Continued research and development are necessary to improve the efficiency and cost-effectiveness of efuel production and to ensure that they are a sustainable and environmentally responsible solution for the future of transportation. This paper will explore efuels and their potential to decarbonize the transportation sector.

An assessment of barriers and solutions for the deployment of electric vehicles in the Brazilian market

The growing concerns about the energy and environmental crisis drive the development of a sustainable society. The electric vehicle (EV) is a potentially clean technology that can contribute to the decarbonization of the transportation sector. However, EVs face obstacles to being diffused and are not prevalent in the global vehicle fleet. Thus, this research identifies the attractiveness, barriers, and solutions for the diffusion of EVs. Semi-structured interviews were conducted with key agents of the Brazilian supply chain of this technology. Results showed that EVs have essential attractions, but there are barriers to their diffusion in the Brazilian market related to EV cost, charging infrastructure, and public policies. The main solutions to overcome these barriers and expand EV adoption involve: (i) increase of emission consumer awareness through promotional campaigns by government and industry, (ii) tax and non-tax incentives, e.g., reduction of taxation on EV purchase or parts of it, reduction of annual fees or special transit permits for EV, and (iii) technological advances, notably in terms of battery performance and availability and efficiency of charging stations. This research comprises aspects of EV diffusion in Brazil but can serve as guidance for other countries with emerging economies or regions where EV adoption is still incipient.

Antisolvent crystallization of battery grade nickel sulphate hydrate in the processing of lateritic ores

Lithium-ion batteries are a crucial part in the rapid, on-going electrification of the global vehicle fleet, which is essential in enabling a transition to a society based on renewable energy. By combining metals including lithium, nickel, cobalt, and manganese in different proportions, cathode active materials with different properties can be obtained. Nickel sulphate hexahydrate, which is of great importance to the battery industry, can be produced by hydrometallurgical processing of lateritic and sulphide ores. Antisolvent crystallization is examined as an alternative to conventional crystallization methods for the production of high-grade nickel sulphate hexahydrate in the processing of lateritic nickel ores from Turkey. The ore has been leached under atmospheric pressure followed by purification by ion exchange resulting in a solution enriched with respect to nickel together with a range of impurity metals from which NiSO4·6H2O can be obtained by antisolvent crystallization. Separate antisolvent crystallization experiments have been carried out for nickel, cobalt and iron sulphate systems, which are the main metals present in the solution, and solubility data has been determined for key conditions. Acetone and isopropanol have been evaluated as antisolvents. Antisolvent crystallization experiments have also been carried out using synthetic solutions and the effect of addition rate of antisolvent, addition of diluted antisolvent and seeding on the purity of the crystals has been investigated. Acetone gives the best product quality in terms of purity and shape. Seeding and a slow rate of addition of dilute antisolvent gives the highest purity of the NiSO4·6H2O crystals. Under optimised conditions, crystals containing 22.3% Ni with a purity of 99.8% by mass have been obtained with a crystallization yield of 63.5%.

CO2-to-Fuels Renewable Gasoline and Jet Fuel Can Soon Be Price Competitive with Fossil Fuels

Download : Download high-res image (69KB) Download : Download full-size image Rob McGinnis, PhD, is an inventor and entrepreneur. He is the founder and CEO of Prometheus, a company that is developing technology to remove carbon dioxide from the air and turn it into fuels. He previously founded Mattershift, where he developed large-scale carbon nanotube membranes. Rob was previously founder of Oasys Water, a company focused on developing forward osmosis technologies for water purification. Rob received his PhD in Engineering from Yale University.

E&amp;P Notes (April 2018)

E&amp;P Notes Alternatives No Threat to Oil, Aramco CEO Says John Donnelly, JPT Editor Alternative energy options and worries about climate change are not a threat to the oil and gas industry, which will need increased investment just to keep up with future demand, said the chief executive officer of Saudi Aramco. The idea that alternatives to hydrocarbons such as electric vehicles will displace oil and gas in the global fuel mix any time soon is a gross oversimplification, Amin Nasser, the head of Saudi Aramco, said during the annual CERAWeek conference by IHS Markit, which took place last month in Houston. “I am not losing any sleep over the idea of peak oil demand or stranded resources,” he said. IEA Sees No End to US Shale Output Surge Matt Zborowski, Technology Writer US crude production is projected to surge to 12.1 million B/D by 2023 amid “a second wave” of shale output increases, making the country the world’s largest oil producer, according to the International Energy Agency’s latest 5-year market forecast. The new wave is underpinned by higher oil prices following the pact between OPEC producers and a group of non-OPEC countries to collectively curb out-put through this year. “Everyone has benefited” from the deal, and newfound optimism has spread through the industry, said OPEC Secretary General Mohammed Barkindo during the CERAWeek conference by IHS Markit in Houston. ExxonMobil Exits Russian Ventures, Continues Success off Guyana Matt Zborowski, Technology Writer ExxonMobil marked a continued companywide transition for the world’s largest public oil and gas firm, headlined by its withdrawal from once-promising Russian joint ventures (JVs) and its announcement of a seventh oil discovery off Guyana. According to a filing with the US Securities and Exchange Commission, ExxonMobil is pulling out of its JVs with Rosneft, established earlier this decade, that involved exploration and development of Arctic, Black Sea, and shale resources. ExxonMobil’s role in those partner-ships was quashed when the US government levied sanctions on Russia in 2014 following its annexation of Crimea and expanded those measures in late 2017. ExxonMobil sued the US Department of the Treasury last year in response to a $2-million fine for violating the 2014 sanctions. BP: Robust Adoption of Electric Vehicles Would Not Stop Oil Consumption Growth Joel Parshall, JPT Features Editor Even a robust adoption of electric vehicles (EVs) over the next 2 decades would not eliminate the growth of either global oil consumption or carbon emissions, BP Chief Economist Spencer Dale said in February as the company introduced its 2018 Energy Outlook. And to meet the goals of the Paris Climate Accord, Dale said, the outlook concludes that a system of global carbon emission pricing and increased regulation to spur energy efficiency and fuel switching would probably be needed in addition to EV adoption. Projecting the future impact of EVs on oil consumption and emissions involves more than counting the number of them and their percentage share in the global vehicle fleet, he said. Another Big Gas Field Starts Production Offshore Egypt Matt Zborowski, Technology Writer The Atoll Phase One project in the East Nile Delta is flowing 350 MMcf/D of gas and 10,000 B/D of condensate to shore after starting up “7 months ahead of schedule and 33% below the initial cost estimate,” operator BP reported. The $1-billion project in the North Damietta concession provides another heavy stream of gas for domestic use in Egypt following the 2017 production launches of the Eni-operated supergiant Zohr field and the BP-operated Taurus and Libra fields of the West Nile Delta development. BP has a 10% stake in the Shorouk concession containing Zohr, which is expected to flow 1 Bcf/D by mid-year. The British supermajor operates the West Nile Delta project with an 82.75% interest in the project partnership.

Resource implications of alternative strategies for achieving zero greenhouse gas emissions from light-duty vehicles by 2060

This paper examines alternative strategies for eliminating the use of oil for passenger transportation in light duty vehicles (LDVs: cars, SUVs and light trucks) by 2060, namely, deep reductions in the energy intensity (MJ/vkm) of LDVs combined with a shift to hybrid and/or all-electric vehicles, or combined with a shift of the residual fuel requirements to C-free fuels (either renewable biofuels or hydrogen produced from C-free energy sources, and used in a fuel cell). Different combinations of these measures have dramatically different implications concerning land area requirements (for biofuels), additional electricity requirements (for electric vehicles or to produce hydrogen electrolytically), and in the demand for potentially limiting metals (Pt, Ru, Li and Nd in particular). Recent estimates of battery, fuel cell and motor sizes in advanced vehicles, and corresponding material loadings, are combined with scenarios for the growth of the global vehicle fleet and recycling potential to estimate future material requirements. For any of the alternative to fossil fuels to be sustainable over the next century, it is essential that LDV energy intensity be pushed to the lowest technically achievable potential, that significant reductions in precious metal loadings be achieved, and that 90% or better recycling efficiency be achieved. Even then, longer term sustainability is not guaranteed, which implies that the primary emphasis in urban development and redevelopment over the next century should be to create cities with little to no dependence on the private automobile for transportation.

Outlook Points to Peak Transport Demand for Oil

Transportation is the linchpin of oil consumption, responsible for more than 50% of the oil that the world uses every day and almost 70% of that consumed daily in the United States. Forecasters all agree that the global vehicle fleet, the dominant factor in transportation demand for oil-based fuels and the major source of transport-sector growth, will expand greatly in the next 20 to 30 years. Thus, it is notable that BP in its 2017 Energy Outlook forecasts, as a base case, that by the mid-2030s, transport demand growth for oil will slow to a trickle, while demand for noncombusted oil use—particularly in the petrochemicals industry—will become the chief driver of oil demand growth. Specifically, over the outlook period of 2017–2035, the growth in transport demand will decelerate from 1 million B/D per year to 0.4 million B/D per year and level off, while the demand for noncombusted oil use will increase by 6 million B/D. Not every forecast agrees with this. The International Energy Agency and ExxonMobil, for example, believe that transport demand will continue to drive oil consumption growth for substantially longer. On the other hand, Shell Chief Executive Officer Ben van Beurden recently said that oil demand as a whole could peak in the early 2030s and possibly sooner with higher biofuel use. There are forecasts from outside the industry that show oil demand peaking and starting to decline sooner rather than later. Implications for Industry The point is not that one forecast or the other is correct, but rather to start thinking about the implications of a transport demand for oil that no longer increases. It is bound to happen at some point, even if the more robust demand forecasts prove correct. What will the industry begin to look like when transport no longer delivers market growth? But first, what is the case for anticipating a slowing and leveling in transport demand by approximately 2035? “It’s largely the significant improvement in the fuel efficiency of the world’s vehicle fleet,” said Mark Finley, general manager of global energy markets and US economics at BP, who was on the team that produced the latest Energy Outlook.

Murine precision-cut lung slices exhibit acute responses following exposure to gasoline direct injection engine emissions

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.

E25 stratified torch ignition engine emissions and combustion analysis

Vehicular emissions significantly increase atmospheric air pollution and greenhouse gases (GHG). This fact associated with fast global vehicle fleet growth calls for prompt scientific community technological solutions in order to promote a significant reduction in vehicle fuel consumption and emissions, especially of fossil fuels to comply with future legislation. To meet this goal, a prototype stratified torch ignition (STI) engine was built from a commercial existing baseline engine. In this system, combustion starts in a pre-combustion chamber, where the pressure increase pushes the combustion jet flames through calibrated nozzles to be precisely targeted into the main chamber. These combustion jet flames are endowed with high thermal and kinetic energy, being able to generate a stable lean combustion process. The high kinetic and thermal energy of the combustion jet flame results from the load stratification. This is carried out through direct fuel injection in the pre-combustion chamber by means of a prototype gasoline direct injector (GDI) developed for a very low fuel flow rate. In this work the engine out-emissions of CO, NOx, HC and CO2 of the STI engine are presented and a detailed analysis supported by the combustion parameters is conducted. The results obtained in this work show a significant decrease in the specific emissions of CO, NOx and CO2 of the STI engine in comparison with the baseline engine. On the other hand, HC specific emission increased due to wall wetting from the fuel hitting in the pre-combustion chamber wall.

EV Market Development Pathways – An Application of System Dynamics for Policy Simulation

The transport sector, in particular road transport, is a major consumer of energy and a major source of greenhouse gas (GHG) emissions, contributing to climate change. There is increasing pressure to reduce CO2 emissions from passenger cars (e.g. in the EU, the Regulation (EC) No 443/2009 sets the limit of CO2 emissions of new passenger cars to 95 g of CO2 from 2020 [1]). Today, the global vehicle stock has more than 1 billion units and relies almost entirely on oil-based energy. According to various projections, the global vehicle fleet could double or even triple by 2050. The energy and environmental implications of such increase would not be negligible. In this context, it is argued that the electrification of the global vehicle fleet emerges as a desirable goal. Electric vehicles (EVs) are expected to help meet key energy and environmental goals, leading to a decrease in oil imports, an increase in energy independency and to a decrease in CO2 emissions. This paper focuses on the EV market penetration in key OECD countries as well as in China and India, considering various vehicle technologies for passenger light-duty vehicles (PLDVs). In particular, the paper investigates the impacts of EVs on oil demand and CO2 emissions in the countries of interest under various scenarios until 2050. For this purpose, a System Dynamics (SD) model is developed and the results of various simulations assessed. The output of the model includes possible future market shares of EVs as well as their specific energy and environmental impacts. Our results show to what extent EVs can potentially contribute to reduce oil dependency and CO2 emissions in the countries analysed beyond 2030.

The isotopic record of Northern Hemisphere atmospheric carbon monoxide since 1950: implications for the CO budget

Abstract. We present a 60-year record of the stable isotopes of atmospheric carbon monoxide (CO) from firn air samples collected under the framework of the North Greenland Eemian Ice Drilling (NEEM) project. CO concentration, δ13C, and δ18O of CO were measured by gas chromatography/isotope ratio mass spectrometry (gc-IRMS) from trapped gases in the firn. We applied LGGE-GIPSA firn air models (Witrant et al., 2011) to correlate gas age with firn air depth and then reconstructed the trend of atmospheric CO and its stable isotopic composition at high northern latitudes since 1950. The most probable firn air model scenarios show that δ13C decreased slightly from −25.8‰ in 1950 to −26.4‰ in 2000, then decreased more significantly to −27.2‰ in 2008. δ18O decreased more regularly from 9.8‰ in 1950 to 7.1‰ in 2008. Those same scenarios show CO concentration increased gradually from 1950 and peaked in the late 1970s, followed by a gradual decrease to present day values (Petrenko et al., 2012). Results from an isotope mass balance model indicate that a slight increase, followed by a large reduction, in CO derived from fossil fuel combustion has occurred since 1950. The reduction of CO emission from fossil fuel combustion after the mid-1970s is the most plausible mechanism for the drop of CO concentration during this time. Fossil fuel CO emissions decreased as a result of the implementation of catalytic converters and the relative growth of diesel engines, in spite of the global vehicle fleet size having grown several fold over the same time period.

Methane emissions from vehicles.

Methane (CH4) is an important greenhouse gas emitted by vehicles. We report results of a laboratory study of methane emissions using a standard driving cycle for 30 different cars and trucks (1995-1999 model years) from four different manufacturers. We recommend the use of an average emission factor for the U.S. on-road vehicle fleet of (g of CH/g of CO2) = (15 +/- 4) x 10(-5) and estimate that the global vehicle fleet emits 0.45 +/- 0.12 Tg of CH4 yr(-1) (0.34 +/- 0.09 Tg of C yr(-1)), which represents < 0.2% of anthropogenic CH4 emissions. This estimate includes the effects of vehicle aging, cold start, and hot running emissions. The contribution of CH4 emissions from vehicles to radiative forcing of climate change is 0.3-0.4% of that of CO2 emissions from vehicles. The environmental impact of CH4 emissions from vehicles is negligible and is likely to remain so for the foreseeable future.

Contribution of vehicle exhaust to the global N2O budget

Assessment of the impact of vehicle emissions on the global environment requires accurate data concerning nitrous oxide (N2O) emissions. We report herein `real world' N2O emissions from road vehicles in a tunnel in Wuppertal, Germany, together with `laboratory' emission measurements conducted at the Ford Motor Company using a chassis dynamometer with a standard driving cycle for 26 different cars and trucks. Consistent results were obtained from both approaches suggesting that a good approximation of the average emission factor (g N2O/g CO2)=(4±2)×10−5. This corresponds to an emission rate of 11-5 mg N2O/km for vehicles with fuel economies of 12-6 l/100 km (20–40 miles/US gallon). N2O emissions from vehicles have a global warming impact, which is 1–2% of that of the CO2 emissions from vehicles. We estimate an annual emission of (0.12±0.06) Tg yr−1 of N2O (0.08±0.04 Tg N yr−1) from the global vehicle fleet which represents 1–4% of the atmospheric growth rate of this species. These results update and supercede our previous study of N2O emissions from vehicles (Becker, K.H., Lörzer, J.C., Kurtenbach, R., Wiesen, P., Jensen, T., Wallington, T.J., 1999. Nitrous oxide (N2O) emissions from vehicles. Environ. Sci. Technol., 33, 4134–4139).

Nitrous Oxide (N2O) Emissions from Vehicles

Assessment of the impact of vehicle emissions on the global environment requires accurate data concerning nitrous oxide, N2O, emissions. We report herein “real-world” N2O emissions from road vehicles in a tunnel in Wuppertal, Germany, together with “laboratory” emission measurements conducted at the Ford Motor Company using a chassis dynamometer with a standard driving cycle for 22 different cars and trucks. Consistent results were obtained from both approaches, suggesting that a good approximation of the average emission factor (g of N2O/g of CO2) = (6 ± 2) × 10-5. This corresponds to an emission rate of 16−8 mg of N2O/km for vehicles with fuel economies of 12−6 L/100 km (20−40 mi/U.S. gal). N2O emissions from vehicles have a global warming impact, which is 1−3% of that of the CO2 emissions from vehicles. We estimate that the global vehicle fleet emits 0.18 ± 0.06 Tg of N2O yr-1 (0.11 ± 0.04 Tg of N yr-1), which represents 2−6% of the atmospheric growth rate of this species. In addition to N2O, laboratory vehicle emission measurements of NH3, HONO, and HCN are reported.