V. Vestreng

Norwegian Meteorological Institute, Kristiania (historical), Oslo County, Norway

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Publications (14)41.03 Total impact

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    ABSTRACT: Quinn, P.K., A. Stohl, A. Baklanov, M.G. Flanner, A. Herber, K.Kupiainen, K.S. Law, J. Schmale, S. Sharma, V. Vestreng, and K. von Salzen, The Arctic, Radiative forcing by black carbon in the Arctic in “State of the Climate in 2013”, Bull. Amer. Meteor, Soc., 95 (7) S124 – 125, 2014.
    Bulletin of the American Meteorological Society 07/2014; 95(7):S124-125. · 11.57 Impact Factor
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    ABSTRACT: Arctic temperatures have increased at almost twice the global average rate over the past 100 years. Warming in the Arctic has been accompanied by an earlier onset of spring melt, a lengthening of the melt season, changes in the mass balance of the Greenland ice sheet, and a decrease in sea ice extent. Short-lived, climate warming pollutants such as black carbon (BC) have recently gained attention as a target for immediate mitigation of Arctic warming in addition to reductions in long lived greenhouse gases. Model calculations indicate that BC increases surface temperatures within the Arctic primarily through deposition on snow and ice surfaces with a resulting decrease in surface albedo and increase in absorbed solar radiation. In 2009, the Arctic Monitoring and Assessment Program (AMAP) established an Expert Group on BC with the goal of identifying source regions and energy sectors that have the largest impact on Arctic climate. Here we present the results of this work and investigate links between mid-latitude pollutants and Arctic climate.
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    ABSTRACT: In recent decades land-based emissions of air pollutants have been substantially reduced over Europe. At the same time emissions from shipping have continued to grow globally. Emissions from international shipping in sea areas surrounding Europe now contribute about 30% of the EU27 emissions of sulphur and NOx and affect ozone levels all over Europe. Although ozone levels are expected to decrease in most parts of Europe, prognoses for 2020 levels are still above what is considered as threshold values. A growing portion of these impacts can be attributed to emissions from international shipping.This paper presents an evaluation of the impacts on ozone levels in the European mainland due to emissions from international shipping. Calculations are carried out under recent (2004) conditions and for a scenario in 2020, where further emission reductions are applied to land based emissions while the ships emissions increase according to their expected growth in transport volumes, without additional technical reduction measures. Impacts are considered with respect to the formation of ground-level ozone, presented as somo35. We investigate the effect of different shipping emission sources, in particular, international shipping inside the 12 mile zone from the coast, emissions from ships outside the 12 mile zone with EU flags and emissions from ships under other flags. It is shown that contributions from EU ships and non-EU and ships outside the 12 mile zone are about equal in magnitude. Corrected for source strength, the largest effect relative to source strength is from emissions within the 12 mile zone. Here ozone titration may cause reductions in somo35 of more than 10% in some countries, or increases of 5% or more elsewhere.
    International Journal of Remote Sensing 08/2009; 30(15-16):4099-4110. DOI:10.1080/01431160902821858 · 1.65 Impact Factor
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    ABSTRACT: European emission trends of nitrogen oxides since 1880 and up to present are presented here and are linked to the evolution of road transport emissions. Road transport has been the dominating source of NOx emissions since 1970, and contributes with 40% to the total emissions in 2005. Five trend regimes have been identified between 1880 and 2005. The first regime (1880-1950) is determined by a slow increase in fuel consumption all over Europe. The second regime (1950-1980) is characterized by a continued steep upward trend in liquid fuel use and by the introduction of the first regulations on road traffic emissions. Reduction in fuel consumption determines the emission trends in the third regime (1980-1990) that is also characterized by important differences between Eastern and Western Europe. Emissions from road traffic continue to grow in Western Europe in this period, and it is argued here that the reason for this continued NOx emission increase is related to early inefficient regulations for NOx in the transport sector. The fourth regime (1990-2000) involves a turning point for road traffic emissions, with a general decrease of emissions in Europe during that decade. It is in this period that we can identify the first emission reductions due to technological abatement in Western Europe. In the fifth regime (2000-2005), the economic recovery in Eastern Europe imposes increased emission from road traffic in this area. Western European emissions are on the other hand decoupled from the fuel consumption, and continue to decrease. The implementation of strict measures to control NOx emissions is demonstrated here to be a main reason for the continued Western European emission reductions. The results indicate that even though the effectiveness of European standards is hampered by a slow vehicle turnover, loopholes in the type-approval testing, and an increase in diesel consumption, the effect of such technical abatement measures is traceable in the evolution of European road traffic emissions over the last 15 years.
    ATMOSPHERIC CHEMISTRY AND PHYSICS 02/2009; 9(4):1503-1520. DOI:10.5194/acp-9-1503-2009 · 5.30 Impact Factor
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    ABSTRACT: Air quality transcends all scales with in the atmosphere from the local to the global with handovers and feedbacks at each scale interaction. Air quality has manifold effects on health, ecosystems, heritage and climate. In this review the state of scientific understanding in relation to global and regional air quality is outlined. The review discusses air quality, in terms of emissions, processing and transport of trace gases and aerosols. New insights into the characterization of both natural and anthropogenic emissions are reviewed looking at both natural (e.g. dust and lightning) as well as plant emissions. Trends in anthropogenic emissions both by region and globally are discussed as well as biomass burning emissions. In terms of chemical processing the major air quality elements of ozone, non-methane hydrocarbons, nitrogen oxides and aerosols are covered. A number of topics are presented as a way of integrating the process view into the atmospheric context; these include the atmospheric oxidation efficiency, halogen and HOx chemistry, night time chemistry, tropical chemistry, heat waves, megacities, biomass burning and the regional hot spot of the Mediterranean. New findings with respect to the transport of pollutants across the scales are discussed, in particular the move to quantify the impact of long-range transport on regional air quality. Gaps and research questions that remain intractable are identified. The review concludes with a focus of research and policy questions for the coming decade. In particular, the policy challenges for concerted air quality and climate change policy (co-benefit) are discussed. doi:10.1016/j.atmosenv.2009.08.021.
    Atmospheric Environment 01/2009; 43(43):5268-5350. DOI:10.1016/j.atmosenv.2009.08.021 · 3.06 Impact Factor
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    ABSTRACT: European emission trends of nitrogen oxides since 1880 and up to present are presented here and are linked to the evolution of road transport emissions. Road transport has been the dominating source of NO<sub>x</sub> emissions since 1970, and contributes with 40% to the total emissions in 2005. Five trend regimes have been identified between 1880 and 2005. The first regime (1880–1950) is determined by a slow increase in fuel consumption all over Europe. The second regime (1950–1980) is characterized by a continued steep upward trend in liquid fuel use and by the introduction of the first regulations on road traffic emissions. Reduction in fuel consumption determines the emission trends in the third regime (1980–1990) that is also characterized by important differences between Eastern and Western Europe. Emissions from road traffic continue to grow in Western Europe in this period, and it is argued here that the reason for this continued NO<sub>x</sub> emission increase is related to early inefficient regulations for NO<sub>x</sub> in the transport sector. The fourth regime (1990–2000) involves a turning point for road traffic emissions, with a general decrease of emissions in Europe during that decade. It is in this period that we can identify the first emission reductions due to technological abatement in Western Europe. In the fifth regime (2000–2005), the economic recovery in Eastern Europe imposes increased emission from road traffic in this area. Western European emissions are on the other hand decoupled from the fuel consumption, and continue to decrease. The implementation of strict measures to control NO<sub>x</sub> emissions is demonstrated here to be a main reason for the continued Western European emission reductions. The results indicate that even though the effectiveness of European standards is hampered by a slow vehicle turnover, loopholes in the type-approval testing, and an increase in diesel consumption, the effect of such technical abatement measures is traceable in the evolution of European road traffic emissions over the last 15 years.
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    ABSTRACT: The regional EMEP chemical transport model has been run for the 1920–2003 period and the simulations compared to the long-term seasonally resolved trends of major inorganic aerosols (sulfate and ammonium) derived from ice cores extracted at Col du Dôme (CDD, 4250 m above sea level, French Alps). Source-receptor calculations have been performed in order to allocate the sources of air pollution arriving over the Alps. Spain, Italy, France, and Germany are found to be the main contributors at CDD in summer, accounting for 50% of sulfate and 75% of ammonium. In winter more European wide and trans-Atlantic contributions are found. The relative impact of these sources remains similar over the whole Alpine massif although transport from US and emissions from Spain contribute less as we move eastward from CDD, toward other alpine ice core drill sites like Colle Gnifetti (CG) in the Swiss Alps. For sulfate, the CDD ice core records and the simulated trends match very well. For ammonium, the trend simulated by the model and the summer ice core record are in reasonable agreement, both showing greater changes in ammonium concentrations than would be suggested by historical ammonia emissions. Motivated by a such good agreement between simulations of past atmospheric concentrations and ice core records for inorganic aerosol species, we also use the model to simulate trends in elemental carbon for which less information on past emission inventories are available.
    Journal of Geophysical Research Atmospheres 09/2007; 112(D23). DOI:10.1029/2006JD008044 · 3.44 Impact Factor
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    ABSTRACT: Abundance of sulphate in Europe has decreased substantially during the last two decades. In this paper, we investigate these recent trends in sulphate concentrations by applying the OsloCTM2 model using three different sets of SO2 emission inventories. We perform time slice model simulations with emissions for the years 1985, 1995 and 2000 and compare our results with observations to investigate if there is consistency between measured and modelled sulphate trends. Overall the model reproduces the levels of sulphur and the decreasing sulphate trends reasonably well, although some discrepancies exist. The model shows a strong reduction in the surface concentration of sulphate similar to the observations, although a slightly smaller decrease. Continental and Eastern Europe experience the largest decrease in sulphate from 1985 to 2000; observations give 65 and 63% decrease, respectively, while modelled decreases are from 42 to 58% depending on the inventory. We have also studied to what extent our model results are sensitive and robust. Based on our model simulations we find that the EMEP emissions of the three sets of emission inventories are best to reproduce the trends in sulphate observations.
    Tellus B 08/2007; 59(4):773 - 786. DOI:10.1111/j.1600-0889.2007.00289.x · 3.76 Impact Factor
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    ABSTRACT: During the last twenty-five years European emission data have been compiled and reported under the Cooperative Programme for Monitoring and Evaluation of the Long-range Transmission of Air Pollutants in Europe (EMEP) as part of the work under the UNECE Convention on Long-range Transboundary Air Pollution (LRTAP). This paper presents emission trends of SO2 reported to EMEP and validated within the programme for the period 1980–2004. These European anthropogenic sulphur emissions have been steadily decreasing over the last twenty-five years, amounting from about 55 Tg SO2 in 1980 to 15 Tg SO2 in 2004. The uncertainty in sulphur emission estimates for individual countries and years are documented to range between 3% and 25%. The relative contribution of European emissions to global anthropogenic sulphur emissions has been halved during this period. Based on annual emission reports from European countries, three emission reduction regimes have been identified. The period 1980–1989 is characterized by low annual emission reductions (below 5% reduction per year and 20% for the whole period) and is dominated by emission reductions in Western Europe. The period 1990–1999 is characterised by high annual emission reductions (up to 11% reduction per year and 54% for the whole period), most pronounced in Central and Eastern Europe. The annual emission reductions in the period 2000–2004 are medium to low (below 6% reduction per year and 17% for the whole period) and reflect the unified Europe, with equally large reductions in both East and West. The sulphur emission reduction has been largest in the sector Combustion in energy and transformation industries, but substantial decreases are also seen in the Non-industrial combustion plants together with the sectors Industrial combustion and Industrial production processes. The majority of European countries have reduced their emissions by more than 60% between 1990 and 2004, and one quarter have already achieved sulphur emission reductions higher than 80%. At European level, the total sulphur target for 2010 set in the Gothenburg Protocol (16 Tg) has apparently already been met by 2004. However, still half of the Parties to the Gothenburg Protocol have to reduce further their sulphur emissions in order to attain their individual country total emission targets for 2010. It is also noteworthy that, contrasting the Gothenburg Protocol requirements, a growing number of countries have recently been reporting increasing sulphur emissions, while others report only minor further decreases. The emission trends presented here are supported by different studies of air concentrations and depositions carried out within and outside the framework of the LRTAP Convention.
    ATMOSPHERIC CHEMISTRY AND PHYSICS 04/2007; 7:3663-3681. DOI:10.5194/acpd-7-5099-2007 · 5.30 Impact Factor
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    E Marmer, B Langmann, H Fagerli, V Vestreng
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    ABSTRACT: Based on historical simulations of the atmospheric distribution of sulfate aerosol over Europe, we have estimated the evolution of the direct shortwave radiative forcing due to sulfate aerosol from 1900 to the present day. Following the trend of atmospheric sulfate burden, the radiative forcing reaches its peak in the 1980s. Since then, environ-mental policies regulating SO x emissions successfully reduced the atmospheric load. On average, the forcing of the year 2000, representing present day, equals that of the 1950s. Spatially, the forcing maxima experienced a shift from the northwest to the southeast during the century. The ship emissions of sulfur keep increasing since the 1980s, hence their relative contribution to the sulfate load and radiative forcing constantly increased -from 3% in the 1980s to over 10% in the year 2000. Forcing is strongest during sum-mertime, with a seasonal mean of –2.7 Wm −2 in the 1980s and –1.2 Wm −2 in summer 2000. The mean forcing efficiency is slightly reduced from –246 W(g sulfate) −1 in the 1900s to –230 W(g sulfate) −1 in the year 2000, it declines with changed geographical distribution of sulfur emissions.
    Journal of Geophysical Research Atmospheres 01/2007; 112(D23). DOI:10.1029/2006JD008037 · 3.44 Impact Factor
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    ABSTRACT: Accurate and complete information on the emissions of persistent organic pollutants (POPs) are essential for interpreting historical, current and future contamination levels in remote areas. However, this information is also crucial for decision makers aiming at further reduction of the environmental loading of these substances on a regional scale. In this study, we identify and discuss specific POP emission inventory features that are deemed essential to understand, predict and control the behaviour of such substances on a European scale. It is shown that the scientific value of official emission data is limited (e.g. for deriving source–receptor relationships on a European scale), as there is insufficient information on spatial, temporal and compound coverage. Likewise, we argue that non-official emission data (i.e. research-driven emission inventories), which are based on aggregated statistics, may be of limited value for the identification of further emission control strategies. It is thus argued that future emission inventories should be developed in a format that is suitable to serve both policy- and research-oriented applications. Further improvement of official emission data with respect to research-driven features seems to be the most sensible way to proceed. Finally, the empirical basis of current emission inventories remains weak, and further research on emission identification and characterisation seem needed (a) to gain confidence in predicted source–receptor relationship as well as (b) for the development of sound control strategies.
    Environmental Science & Policy 10/2006; 9(7-8):663-674. DOI:10.1016/j.envsci.2006.09.001 · 3.51 Impact Factor
  • D. Simpson, P. Makar, V. Vestreng
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    ABSTRACT: The formation of secondary organic aerosols (SOA) in ambient air depends on a number of factors, including: (1) emissions of primary organic carbon (OC), (2) emissions of precursor VOC (both biogenic and anthropogenic), (3) the formation of condensible compounds through atmospheric chemistry, and (4) the ensuing gas-particle partitioning of these compounds. Factors (3) and (4) are the least understood of these, although great progress has been made in smog-chamber studies at least. This study address the relative importance of all of these factors for atmospheric conditions through the application of the EMEP MSC-W regional transport model over Europe. Previous modelling of SOA over European made use of the Lagrangian EMEP model (Andersson-Sköld and Simpson, 2000) which suffers from a low horizontal resolution (150x150 km2) and, more seriously, from a one-layer formulation. This earlier work also made the assumption that activity coefficients for SOA compounds were unity; an assumption which may sometimes be acceptable (e.g. Seinfeld et al., 2002) but which is not always adequate and requires investigation for ambient modelling conditions. This study reports on the results of a new and much more detailed set of calculations. Three major improvements have been implemented. Firstly, we have made use of the new EMEP Eulerian model (Simpson et al., 2002), which has a horizontal resolution of 50x50 km2 and 20 vertical layers. Secondly, emissions of primary OC are estimated based upon available PM2.5 inventories and a new evaluation of those VOC species which are potentially important in SOA formation (Makar et al., 2003). Thirdly, the UNIFAC group-contribution method (Sandler, 1999, Makar et al., 2003) is used to estimate the activity coefficients of the aerosol components and thus provide a more rigorous treatment of the gas-particle partitioning. References Andersson-Sköld, Y., and Simpson, D., 2001, Secondary organic aerosol formation in Northern Europe: a model study. J. Geophys. Res. 106, D7 7357-7374. Makar, P.A., Moran, M.D., Scholtz, M.T., and Taylor, A., 2003, Speciation of volatile organic compound emissions for regional air quality modelling of particulate matter and ozone, J.Geophys., Res., in press. Sandler, S.I., 1999, Chemical and Engineering Thermodynamics, 3rd edition, Wiley. Seinfeld, J.H., Erdakos, G.B., Asher, W.E. and Pankow, J.F., 2001, Modeling the formation of secondary organic aerosol (SOA). 2. The predicted effects of relative humidity on aerosol formation in the apha-pinene, beta-pinene sabinene, Delta^3-carene, and cyclohexane-ozone systems, Env. Sci. Technol., 35, 1806-1817. Simpson, D., Fagerli, H., Jonson, J.E., Tsyro, S. and Wind, P., 2002, The Unified EMEP Modelling System, pp 5-13, EMEP Report 1&2/2002, Transboundary acidification, eutrophication and ground-level ozone in Europe. Norwegian Meteorological Institute, Oslo, Norway
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    ABSTRACT: The implementation of strict measures to control NO x emissions from road transport is demonstrated here to be a main reason for the continued Western European emission reductions. The results indicate that even though the effectiveness of European standards (EURO 1-4) is hampered by a slow vehicle turnover, loopholes in the type-approval testing, and an increase in diesel consumption, the effect of such technical abatement measures is traceable in the evolution of European road traffic emissions over the last 15 years. Transport emissions increase in line with the growth in economy in large parts of Eastern Europe. As a result of the recent development in road transport emissions, the emission levels in Eastern and Western Europe are now rapidly approaching each other.
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    ABSTRACT: Air quality transcends all scales with in the atmosphere from the local to the global with handovers and feedbacks at each scale interaction. Air quality has manifold effects on health, ecosystems heritage and, climate. In this review the state of scientific understanding in relation to global and regional air quality is outlined. The review discusses air quality, in terms of emissions, processing and transport of trace gases and aerosols. New insights into the characterization of both natural and anthropogenic emissions are reviewed looking at both natural (e.g. dust and lightning) as well as plant emissions. Trends in anthropogenic emissions both by region and globally are discussed as well as biomass burning emissions. In terms of chemical processing the major air quality elements of ozone, non-methane hydrocarbons, nitrogen oxides and aerosols are covered. A number of topics are presented as a way of integrating the process view into the atmospheric context; these include the atmospheric oxidation efficiency, halogen and HOx chemistry, nighttime chemistry, tropical chemistry, heat waves, megacities, biomass burning and the regional hot spot of the Mediterranean. New findings with respect to the transport of pollutants across the scales are discussed, in particular the move to quantify the impact of long-range transport on regional air quality. Gaps and research questions that remain intractable are identified. The review concludes with a focus of research and policy questions for the coming decade. In particular, the policy challenges for concerted air quality and climate change policy (co-benefit) are discussed. (C) 2009 Elsevier Ltd. All rights reserved.