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  • 51. Emmons, L. K.
    et al.
    Arnold, S. R.
    Monks, S. A.
    Huijnen, V.
    Tilmes, S.
    Law, K. S.
    Thomas, J. L.
    Raut, J. -C
    Bouarar, I.
    Turquety, S.
    Long, Y.
    Duncan, B.
    Steenrod, S.
    Strode, S.
    Flemming, J.
    Mao, J.
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Thompson, A. M.
    Tarasick, D.
    Apel, E. C.
    Blake, D. R.
    Cohen, R. C.
    Dibb, J.
    Diskin, G. S.
    Fried, A.
    Hall, S. R.
    Huey, L. G.
    Weinheimer, A. J.
    Wisthaler, A.
    Mikoviny, T.
    Nowak, J.
    Peischl, J.
    Roberts, J. M.
    Ryerson, T.
    Warneke, C.
    Helmig, D.
    The POLARCAT Model Intercomparison Project (POLMIP): overview and evaluation with observations2015In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 15, no 12, p. 6721-6744Article in journal (Refereed)
    Abstract [en]

    A model intercomparison activity was inspired by the large suite of observations of atmospheric composition made during the International Polar Year (2008) in the Arctic. Nine global and two regional chemical transport models participated in this intercomparison and performed simulations for 2008 using a common emissions inventory to assess the differences in model chemistry and transport schemes. This paper summarizes the models and compares their simulations of ozone and its precursors and presents an evaluation of the simulations using a variety of surface, balloon, aircraft and satellite observations. Each type of measurement has some limitations in spatial or temporal coverage or in composition, but together they assist in quantifying the limitations of the models in the Arctic and surrounding regions. Despite using the same emissions, large differences are seen among the models. The cloud fields and photolysis rates are shown to vary greatly among the models, indicating one source of the differences in the simulated chemical species. The largest differences among models, and between models and observations, are in NOy partitioning (PAN vs. HNO3) and in oxygenated volatile organic compounds (VOCs) such as acetaldehyde and acetone. Comparisons to surface site measurements of ethane and propane indicate that the emissions of these species are significantly underestimated. Satellite observations of NO2 from the OMI (Ozone Monitoring Instrument) have been used to evaluate the models over source regions, indicating anthropogenic emissions are underestimated in East Asia, but fire emissions are generally overestimated. The emission factors for wildfires in Canada are evaluated using the correlations of VOCs to CO in the model output in comparison to enhancement factors derived from aircraft observations, showing reasonable agreement for methanol and acetaldehyde but underestimate ethanol, propane and acetone, while overestimating ethane emission factors.

  • 52.
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    Assessing ground-level ozone (O3) impacts to crops in parts of Asia and southern Africa: The Regional Air Pollution in Developping Countries (RAPIDC) Crops Project.2010In: Air Pollution Health and Environmental Impacts, CRC Press , 2010, p. 421-446Chapter in book (Other academic)
  • 53.
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    Modelling of near-surface ozone over South Asia2008In: Journal of Atmospheric Chemistry, ISSN 0167-7764, E-ISSN 1573-0662, Vol. 59, no 1, p. 61-80Article in journal (Refereed)
    Abstract [en]

    Hourly, three-dimensional, fields of tropospheric ozone have been produced for 12 consecutive months on a domain covering South Asia, using the regional Eulerian off-line chemistry transport model MATCH. The results were compared with background observations to investigate diurnal and seasonal variations of near-surface ozone in the region. MATCH reproduced the seasonality of near-surface ozone at most locations in the area. However, the current, and previous, studies indicate that the model consequently overestimate night-time concentrations, while it occasionally underestimates the day-time, near-surface, ozone concentrations. The lowest monthly-mean concentrations of near-surface ozone are typically experienced in June-September, coincident with the rainy season in most areas. The seasonality is not identical across the domain; some locations have a completely different trend. Large areas in Northern India and Nepal show a secondary minimum during the cold winter season (December-January). High concentrations of near-surface ozone are found over the oceans, close to the Indian subcontinent, due to the less efficient dry deposition to water surfaces; over parts of Tibet due to influence of free tropospheric air and little deposition to snow covered surfaces; and along the Gangetic valley due to the large emissions of precursors in this region. Monthly-mean ozone concentrations in the densely populated northern India range from 30-45 ppb(v). The model results were also used to produce maps of AOT40. The results point towards similar levels of AOT40 in India as in Europe: large areas of India show 3-month AOT40 values above 3 ppm(v) hours.

  • 54.
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    Sulphur simulations for East Asia using the MATCH model with meteorological data from ECMWF2000Report (Other academic)
  • 55.
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    Sulphur simulations for East Asia using the match model with meteorological data from ECMWF2001In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 130, no 1-4, p. 289-294Article in journal (Refereed)
    Abstract [en]

    Sulphur transport and conversion calculations have been conducted over an East Asian domain as part of a model intercomparison exercise. We hereby describe the MATCH model, used in the study, and discuss the results achieved with different model configurations. We find that is often more critical to choose a representative gridbox value than selecting a specific parameter value from the suite available. The modelled, near-surface, atmospheric concentration of total-sulphur (SO2+sulphate) in eastern China is typically 5-10 mug S m(-3), with large areas exceeding 20 mug S m(3). In southern Japan the values range from 2-5 mug S m(-3). Atmospheric SO2 dominates over sulphate near the emission regions while sulphate concentrations are higher over e.g. the western Pacific. The sulphur deposition exceeds several g sulphur m(-2) year m(-1) in large areas of China. Southern Japan receives 0.5-1 S m(-2) year(-1).

  • 56.
    Engardt, Magnuz
    et al.
    SMHI, Research Department, Air quality.
    Alpfjord, Helene
    SMHI, Professional Services.
    Andersson, Camilla
    SMHI, Research Department, Air quality.
    PODY-beräkningar med MATCH Sverigesystemet2016Report (Other academic)
    Abstract [en]

    We have developed a set of programs that enable PODY calculations in the air quality surveillance system MATCH Sverigesystemet. This report gives a brief overview of PODY calculations in general and the MATCH implementation in particular.

    We present results for the receptors generic crops (POD3gen-CR) and generic deciduous trees (POD1gen-DT) for the years 2013-2015 and contrast these with corresponding data from the EMEP-model. The POD3gen-CR values calculated by MATCH feature large inter-annual variations and are significantly higher than the corresponding assessment by the EMEP-model. POD1gen-DT show smaller inter-annual variation and the MATCH and the EMEP-model results correspond better.

    PODY is presented together with other ozone metrics on the SMHI environmental mapping web page (www.smhi.se/klimatdata/miljo/atmosfarskemi) starting from the mapping year 2013.

  • 57.
    Engardt, Magnuz
    et al.
    SMHI, Research Department, Air quality.
    Andersson, Camilla
    SMHI, Research Department, Air quality.
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Modellering av marknära ozon: Regionala och högupplösta tillämpningar av MATCH2011Report (Other academic)
    Abstract [en]

    High concentrations of near-surface ozone in Sweden occur predominantly during spring and summer in the Southwestern part of the country. SMHI’s regional dispersion model, MATCH, complies with the Air Quality Directive on model quality for ozone in the background air of Sweden. This applies both to a European scale application with 44×44 km2 grid squares as well as a highresolution application with 5×5 km2 grid squares. High-resolution modelling marginally improves the statistical scores that describe model quality. Local contribution to ozone exceedances (in suburbs) is probably not a problem in Sweden .Although the MATCH model meets the Air Quality Directive’s demands on model quality does it occasionally miss the episodes with the highest concentrations. This is a severe shortcoming in the modelling system. More accurate information about the emissions of ozone producing substances, in particular in Eastern Europe, and improvements in the model’s description of vertical mixing and deposition is probably needed to improve the model. Two-dimensional variational data analysis could be a tool to achieve a more accurate geographical coverage of ozone-fields in Sweden. This applies, in particular, for AOT40 and number of days exceeding a threshold. MATCH results, including two-dimensional variational data analysis, can be used in combination with measurements to monitor near-surface ozone in Sweden.

  • 58.
    Engardt, Magnuz
    et al.
    SMHI, Research Department, Air quality.
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Andersson, Camilla
    SMHI, Research Department, Air quality.
    Climate and Emission Changes Contributing to Changes in Near-surface Ozone in Europe over the Coming Decades: Results from Model Studies2009In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 38, no 8, p. 452-458Article in journal (Refereed)
    Abstract [en]

    We used an off-line, regional, model of atmospheric transport and chemistry to investigate current and future levels of near-surface ozone and accumulated ozone exposure over a threshold of 40 ppb(v) (AOT40) in Europe. To describe the current situation and enable an evaluation of the model's performance we simulated a number of years around 2000. To assess changes in ozone concentrations due to possible emission changes in Europe, the model was run with the meteorology of the early 2000s and precursor emissions from a set of Clean Air for Europe (CAFE) emissions scenarios. By extrapolation of the observed increase in near-surface O(3) at coastal locations in northwest Europe we constructed model boundaries that were used to simulate the impact of increasing hemispheric background in 2020. To assess changes in ozone concentrations due to climate change, the model was run with recent (2000) emissions but using meteorology from a regional climate model simulating a control (1961-1990) and a future (2021-2050) climate. The results indicate that climate change will have a small impact on ozone concentrations and AOT40 in the Nordic countries. Changes in hemispheric background concentrations and changes in precursor emissions in Europe will have a larger effect on ozone in Northern Europe. The situation is quite different in southern Europe, where climate change is expected to result in a very large increase in near-surface ozone concentrations.

  • 59.
    Engardt, Magnuz
    et al.
    SMHI, Research Department, Air quality.
    Foltescu, Valentin
    SMHI, Research Department, Air quality.
    Luftföroreningar i Europa under framtida klimat2007Report (Other academic)
    Abstract [en]

    In order to investigate the effects of climate change on air quality in Europe, we have utilised the regional CTM (chemistry and transport model) MATCH, forced by meteorology representing future climate conditions but keeping the emissions at their current value. The meteorology is from RCA3, the Rossby Center’s regional climate model (covering all Europe on 50 km × 50 km resolution). RCA3 is, in the current study, run under the SRES A2 emission scenario forced with corresponding climate data from ECHAM4/OPYC3 global model on its boundaries. We have applied our CTM on three different 30-year periods representing current, near- and distant future climate (1961-1990, 2021-2050 and 2071-2100, respectively). Detailed description and validation of the climate model and the CTM is given elsewhere. In the present report we report seasonally-averaged changes in near-surface ozone, secondary inorganic aerosols (SIA) and deposition of sulphur and nitrogen containing species in Europe.The seasonal-mean ozone concentrations are expected to increase considerably (1-2% per decade up to 2050) in central and southern Europe, in particular during summer. The daily maximum concentrations are expected to increase even more than the daily mean concentrations. Northernmost Europe is projected to experience lower ozone concentrations under future climate, especially during spring and autumn. The concentration of SIA will increase dramatically in continental Europe during all seasons except winter. The increase is largest around the Mediterranean during summer. The average summertime concentration of SIA will be 20% higher in 2021-2050 and 50% higher in 2071-2100 compared to current levels as a result of changing the meteorology (drier and warmer conditions in central and southern Europe). The increase in atmospheric SIA concentrations is related to the large decrease in wet deposition of sulphur- and nitrogen containing species, which will be the consequence of climate change in large parts of central and southern Europe. Large areas around the Mediterranean, France, Belgium and the Netherlands will receive 50%, or less, of current nitrogen- and sulphur deposition in 2071-2100 compared to present conditions. The Norwegian coast, on the other hand, is expected to receive more sulphur- and nitrogen deposition due to the anticipated increase in precipitation in this area.

  • 60.
    Engardt, Magnuz
    et al.
    SMHI, Research Department, Air quality.
    Holmen, K
    Model simulations of anthropogenic-CO2 transport to an Arctic monitoring station during winter1999In: Tellus. Series B, Chemical and physical meteorology, ISSN 0280-6509, E-ISSN 1600-0889, Vol. 51, no 2, p. 194-209Article in journal (Refereed)
    Abstract [en]

    We describe, and use, a limited area, 3-dimensional transport model. The model domain is located over the Arctic, but includes the majority of the anthropogenic CO2 emissions in western and eastern Europe, which together make up about 1/3 of the global CO2 emissions. The model is run for several winter periods, using anthropogenic CO2 emissions only, and the results are compared with independent CO2 measurements taken at a monitoring station on Spitsbergen in the high Arctic. We show that the initial concentrations and boundary values of the domain are not crucial for the results, and conclude that most of the measured variability above the winter baseline in CO2 at the Arctic monitoring station emanates from recent CO2 sources within the model domain. From the observed small spatial variability in the monthly mean atmospheric CO2 mixing ratio in the north Atlantic region, we assume that there is only little net exchange between the atmosphere and ocean during the studied periods. Based on the co-variation between CO2 and particulate mass,we hypothesise that most of the measured CO2 variability is due to anthropogenic fossil fuel emissions, although we can not rule out a biogenic CO2 component. Using the transport model, we compare different estimates of fossil-fuel consumption in the mid-latitudes. We find that the industrial centres and the surrounding gas-fields in the lower-Ob region (60 degrees-72 degrees N, 65 degrees-80 degrees E) occasionally have a much larger impact on the CO2 measurements at Spitsbergen than follows from a recent CO2 emission inventory. This implies that there may be an overlooked CO2 source in this region, possibly flaring of gas.

  • 61.
    Engardt, Magnuz
    et al.
    SMHI, Research Department, Air quality.
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Simulations of future sulphur and nitrogen deposition over Europe using meteorological data from three regional climate projections2013In: Tellus. Series B, Chemical and physical meteorology, ISSN 0280-6509, E-ISSN 1600-0889, Vol. 65, article id 20348Article in journal (Refereed)
    Abstract [en]

    We use a regional model of atmospheric chemistry and transport to investigate trends in sulphur and nitrogen deposition over Europe during the first half of the 21st century. To assess changes due to climate change, the model was operated with meteorology from a regional climate model simulating present and future climates. The sensitivity of the deposition calculations to uncertainties in the climate projections was explored by using output from three different climate models. Changes in anthropogenic air pollution emissions in Europe were extracted from the gridded RCP4.5 emission inventory. The modelling systems were evaluated by comparing average modelled precipitation, deposition and concentrations over a 20-year period with observations collected around the year 2000. We conclude that the deposition of sulphur and nitrogen containing species will mainly be governed by changes in European emissions of these species over the period 2000-2050. If future emissions follow the pathway of the RCP4.5 scenario, Europe can expect significantly lower deposition of sulphur and oxidised nitrogen in 2050 compared to 2000. For reduced nitrogen, large areas of western Europe will receive considerably more deposition in 2050 than in 2000, due to feedback of decreased sulphur concentrations on the atmospheric turnover time of reduced nitrogen. Domain averaged reductions of total deposition from 2000 to 2050 are 63, 41 and 0.9% for sulphur, oxidised-and reduced nitrogen, respectively. Climate change results in decreased wet deposition of sulphur and reduced nitrogen leading to increased atmospheric turnover time of these species. Climate and emission changes lead to decreased atmospheric turnover times of reduced nitrogen but increased atmospheric turnover times of sulphur and oxidised nitrogen. These relations are likely leading to altered source-receptor relations in the future.

  • 62.
    Engardt, Magnuz
    et al.
    SMHI, Research Department, Air quality.
    Leong, C P
    Regional modelling of anthropogenic sulphur in Southeast Asia2001In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 35, no 34, p. 5935-5947Article in journal (Refereed)
    Abstract [en]

    A co-operative research project between the Malaysian Meteorological Service (MMS) and the Swedish Meteorological and Hydrological Institute (SMHI) focussing on the usage of an atmospheric transport and chemistry model, has just been initiated. Here, we describe the main features of the dispersion model and discuss a first set of calculations in light of available measurements of sulphuric species in Southeast Asia. According to our results, anthropogenic sulphur concentrations and depositions are particularly high near the large cities of the region, around a metal smelter in the southern Philippines, and in a region extending from northern Vietnam into southeastern China. These areas coincide with the high-emissions regions of Southeast Asia and we tentatively conclude that regional transport of acidifying species is not as far-reaching as in the mid-latitudes. From our calculations, and from supporting measurements we conclude that most of rural Southeast Asia is not yet severely affected by anthropogenic sulphur, but given the rapid rate of economical development in this region the situation may deteriorate quickly. Areas that are particularly at risk include the large cities, northern Vietnam, most of central Thailand, most of peninsular Malaysia, eastern Sumatra and parts of Java, all of which receive total-sulphur depositions in excess of 0.5 g S m(-2) yr(-1). Our model simulates sulphate in precipitation in accordance with measurements, but it has a tendency to overestimate atmospheric SO2. It remains to be investigated whether this is a problem in the model formulation or a result of unrepresentative sampling. An immediate continuation of this study should be performed with higher spatial resolution than the currently used 100 x 100 km(2). Other imperfections in this model study, which should be addressed in future work, include parameterised vertical transport in deep convective clouds, the influence of natural emissions (primarily from volcanoes) on the concentration and deposition of sulphuric species, and the year-to-year variability of the driving meteorological conditions. (C) 2001 Elsevier Science Ltd. All rights reserved.

  • 63.
    Engardt, Magnuz
    et al.
    SMHI, Research Department, Air quality.
    Simpson, David
    Schwikowski, Margit
    Granat, Lennart
    Deposition of sulphur and nitrogen in Europe 1900-2050. Model calculations and comparison to historical observations2017In: Tellus. Series B, Chemical and physical meteorology, ISSN 0280-6509, E-ISSN 1600-0889, Vol. 69, article id 1328945Article in journal (Refereed)
  • 64.
    Engardt, Magnuz
    et al.
    SMHI, Research Department, Air quality.
    Siniarovina, U
    Khairul, N I
    Leong, C P
    Country to country transport of anthropogenic sulphur in Southeast Asia2005In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 39, no 28, p. 5137-5148Article in journal (Refereed)
    Abstract [en]

    The MATCH model-driven by archived meteorological data from the ECMWF-has been used to study the long-range transport of pollutants in Southeast Asia during the year 2000. We have specifically investigated the atmospheric export and import of anthropogenic sulphur between nine countries in Southeast Asia as well as the import to these countries from the boundaries of our model domain, from southern China, and from international shipping in the surrounding waters. Compared to the conditions at the mid-latitudes (Europe, North America and East Asia), we find less long-range transport in this part of the world. In all countries in the region (except those with very small area, i.e. Singapore and Brunei), did the major part of the domestic emissions (60-70%) fall down on the emitting country itself. The fraction of the countries own emissions contributing to the total, annually accumulated, national deposition varied from 10% for Laos-which is a country with small emissions neighbouring large emitters-to 80-90% in countries not surrounded by significant emitters (i.e. Thailand, Indonesia, Singapore and Brunei). Sensitivity tests were performed to explore the uncertainties in the model simulations and to investigate to what extent the current results could be used for source-receptor relationships in the future, when the magnitude and location of the emissions may be different. We found that the general feature-with relatively little long-range transport of sulphur-will not be altered, while the absolute magnitude of the deposition in areas downwind of large emitters could change considerably if certain model parameters, or the emission patterns are changed. This is particularly true in light of the seasonal variation of the deposition pathways. The atmospheric import of anthropogenic sulphur from specific countries can vary by an order of magnitude between different months. Incidentally, a decrease in import from one country during a certain period is often compensated by a roughly equal increase of the import from another country during the same time. (c) 2005 Elsevier Ltd. All rights reserved.

  • 65. Eriksson, Charlotta
    et al.
    Nilsson, Mats E.
    Willers, Saskia M.
    Gidhagen, Lars
    SMHI, Research Department, Air quality.
    Bellander, Tom
    Pershagen, Goran
    Traffic noise and cardiovascular health in Sweden: The roadside study2012In: Noise & Health, ISSN 1463-1741, E-ISSN 1998-4030, Vol. 14, no 59, p. 140-147Article in journal (Refereed)
    Abstract [en]

    Long-term exposure to traffic noise has been suggested to increase the risk of cardiovascular diseases (CVD). However, few studies have been performed in the general population and on railway noise. This study aimed to investigate the cardiovascular effects of living near noisy roads and railways. This cross-sectional study comprised 25,851 men and women, aged 18-80 years, who had resided in Sweden for at least 5 years. All subjects participated in a National Environmental Health Survey, performed in 2007, in which they reported on health, annoyance reactions and environmental factors. Questionnaire data on self-reported doctors diagnosis of hypertension and/or CVD were used as outcomes. Exposure was assessed as Traffic Load (millions of vehicle kilometres per year) within 500 m around each participants residential address. For a sub-population (n = 2498), we also assessed road traffic and railway noise in L den at the dwelling facade. Multiple logistic regression models were used to assess Prevalence Odds Ratios (POR) and 95 Confidence Intervals (CI). No statistically significant associations were found between Traffic Load and self-reported hypertension or CVD. In the sub-population, there was no association between road traffic noise and the outcomes; however, an increased risk of CVD was suggested among subjects exposed to railway noise >= 50 dB(A); POR 1.55 (95 CI 1.00-2.40). Neither Traffic Load nor road traffic noise was, in this study, associated with self-reported cardiovascular outcomes. However, there was a borderline-significant association between railway noise and CVD. The lack of association for road traffic may be due to methodological limitations.

  • 66. Fauser, P.
    et al.
    Ketzel, M.
    Becker, T.
    Plejdrup, M. S.
    Brandt, J.
    Gidhagen, Lars
    SMHI, Research Department, Air quality.
    Omstedt, Gunnar
    SMHI, Research Department, Air quality.
    Skarman, T.
    Bartonova, A.
    Schwarze, P.
    Karvosenoja, N.
    Paunu, V. -V
    Kukkonen, J.
    Karppinen, A.
    Human exposure to carcinogens in ambient air in Denmark, Finland and Sweden2017In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 167, p. 283-297Article in journal (Refereed)
  • 67. Felix, Erika
    et al.
    Gidhagen, Lars
    SMHI, Research Department, Air quality.
    Alonso, Marcelo F.
    Nahirny, Everaldo P.
    Alves, Bruno L.
    Segersson, David
    SMHI, Research Department, Air quality.
    Amorim, Jorge Humberto
    SMHI, Research Department, Air quality.
    Passive sampling as a feasible tool for mapping and model evaluation of the spatial distribution of nitrogen oxides in the city of Curitiba, Brazil2019In: Air quality, atmosphere and health, ISSN 1873-9318, E-ISSN 1873-9326, Vol. 12, no 7, p. 837-846Article in journal (Refereed)
  • 68.
    Foltescu, Valentin
    et al.
    SMHI, Research Department, Air quality.
    Gidhagen, Lars
    SMHI, Research Department, Air quality.
    Omstedt, Gunnar
    SMHI, Research Department, Air quality.
    Nomogram för uppskattning av halter av PM10 och NO2: Reviderad version (december 2004)2001Report (Other academic)
    Abstract [sv]

    Den nya förordningen om miljökvalitetsnormer för utomhusluft (SFS 2001:527) definierar normvärden och utvärderingströsklar för bl a NO2 och PM10. SMHI har av Naturvårdsverket och Vägverket fått i uppgift att ta fram en enkel metod att användas för en första ut-värdering av luftföroreningshalterna. Metoden består av s k nomogram för skattning av årsmedelvärden genererade av emissionerfrån en individuell gata eller väg. Till det lokalt genererade värdet ska läggas ett bakgrundsvärde. Empiriska relationer byggda på historiska mätserier har också tagits fram för att från medelvärdet kunna uppskatta extremvärden i form av percentiler.Utvärderingsmetodiken som beskrivs i denna rapport är avsedd att användas för en första uppskattning av föroreningshalterna på platser där mätningar saknas. Om de uppskattade halterna ligger under denedre utvärderingströsklarna, räcker nomogrammens resultat som underlag. Om de uppskattade halterna är högre, behövs en noggrannare utvärdering med hjälp av modeller och/eller mätning. Ibilaga 1 beskrivs metoden praktiskt.

  • 69.
    Foltescu, Valentin
    et al.
    SMHI, Research Department, Air quality.
    Häggmark, Lars
    SMHI, Core Services.
    Jämförelse mellan observationer och fält med griddad klimatologisk information1997Report (Other academic)
  • 70.
    Foltescu, Valentin
    et al.
    SMHI, Research Department, Air quality.
    Persson, Christer
    SMHI, Research Department, Air quality.
    Beräkning av moln- och dimdepositionen i Sverigemodellen – Resultat för 1997 och 1998: Estimation of cloud and fog deposition by use of ”Sverigemodellen” – Results for 1997 and 19982001Report (Other academic)
    Abstract [en]

    The capture of cloud and fog droplets by vegetation as a possibly important deposition mechanism has been recognised lately after reports of increased forest decline with altitude. We are concerned with interception, impaction and stickiness of polluted cloud water and fog droplets to terrestrial surfaces, including forest canopies. This deposition is mediated by low-level clouds, in which parts of the terrain can be immersed, or by the presence of orographic and radiation fog. In this study the transport of cloud and fog droplets towards terrestrial surfaces is parameterised and the “occult” deposition (mediated by both clouds and fog) is calculated by a new approach, implemented in “Sverigemodellen” (MATCH-Sverige), a 3D Eulerian transport and dispersion model employed for making environmental assessments in Sweden.The model scheme is taking into account the mesoscale analysis (MESAN) of low-cloud coverage and cloud-base height, the visibility analysis, detailed topography information, land use, modelled atmospheric concentrations and the instantaneous deposition parameters for the investigated species (acidifying air pollutants: sulphate and oxidised/reduced nitrogen).The model scheme is validated by comparing with throughfall monitoring of sulphate deposition to coniferous forests at elevated sites in the Swedish mountains. It shows a rather good fit to the measurements, generally within 25%, which is deemed as encouraging. Discrepancies exist though and are subject of discussion. The percentage of occult deposition can be up to 115% of the sum of dry and wet deposition. Therefore we cannot ignore this contribution in the assessments of deposition of acidifying pollutants. The highest fluxes of cloud deposition are assigned to mountainous regions in Northern Sweden, while the highest fog deposition is calculated at a location in Jönköpings County, on the Sydsvenska höglandet.

  • 71.
    Foltescu, Valentin
    et al.
    SMHI.
    Pryor, S C
    Bennet, Cecilia
    SMHI, Research Department, Air quality.
    Sea salt generation, dispersion and removal on the regional scale2005In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 39, no 11, p. 2123-2133Article in journal (Refereed)
    Abstract [en]

    The MATCH (Multi-scale Atmospheric Transport and Chemistry) modelling system has been used as the modelling platform for regional-scale sea salt simulations. A new model version for sea salt aerosols has been constructed and assessed. This study presents the model concept and shows that the model is capable of simulating sea salt on a regional scale. The model agrees well with observations, particularly in terms of the sea salt mass concentrations at certain locations in Northern Europe. The observed wet fluxes are generally under-predicted due in part to systematic under-prediction of precipitation by the meteorological model used to drive MATCH. (c) 2005 Elsevier Ltd. All rights reserved.

  • 72.
    Fredriksson, Ulf
    et al.
    SMHI, Core Services.
    Krieg, Roland
    SMHI, Research Department, Air quality.
    En överskalig klimatstudie för Tornby, Linköping1987Report (Other academic)
  • 73.
    Fredriksson, Ulf
    et al.
    SMHI, Core Services.
    Persson, Christer
    SMHI, Research Department, Air quality.
    NOx- och NO2-beräkningar vid Vasaterminalen i Stockholm1985Report (Other academic)
  • 74.
    Fredriksson, Ulf
    et al.
    SMHI, Core Services.
    Persson, Christer
    SMHI, Research Department, Air quality.
    Laurin, Sten
    SMHI.
    Helsingborgsluft1985Report (Other academic)
  • 75.
    Funquist, Lennart
    et al.
    SMHI, Research Department, Oceanography.
    Gidhagen, Lars
    SMHI, Research Department, Air quality.
    Svensson, Urban
    SMHI, Research Department, Oceanography.
    THE MATHEMATICAL-MODELING OF BAROCLINIC WAVES AND FRONTS IN THE OCEAN1987In: Applied Mathematical Modelling, ISSN 0307-904X, E-ISSN 1872-8480, Vol. 11, no 1, p. 11-18Article in journal (Refereed)
  • 76. Gallardo, L
    et al.
    Olivares, G
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Aarhus Andrae, Bodil
    SMHI, Core Services.
    Coastal lows and sulfur air pollution in Central Chile2002In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 36, no 23, p. 3829-3841Article in journal (Refereed)
    Abstract [en]

    Air pollutants in Santiago (33.5degreesS, 70.8degreesW, 500m a.s.l.), a city with 5 million inhabitants, located in a basin in Central Chile surrounded by the high Andes, frequently exceed air quality standards. This affects human health and it stresses vegetation. The most extreme winter and fall pollution events occur when the subsident regime of the Pacific high is further enhanced by coastal lows (CLs), which bring down the base of the subsidence inversion. Under these conditions, the air quality worsens significantly giving rise to acute air pollution episodes. We assess the ability of a regional transport/chemistry/deposition model (MATCH) coupled to a meteorological model (High Resolution Limited Area Model-HIRLAM) to simulate the evolution of oxidized sulfur (SOx) in connection with intensive CLs. We focus on SOx since it is an environmental issue of concern, and the emissions and concentrations of SOx have been regularly monitored making it easier to bracket model outputs for SOx than for other pollutants. Furthermore, the SOx emissions in the area are very large, i.e., about 0.4% of the global anthropogenic sources. Comparisons with observations indicate that the combination of HIRLAM and MATCH is a suitable tool for describing the regional patterns of dispersion associated with CLs. However, the low number and the limited geographical coverage of reliable air quality data preclude a complete evaluation of the model. Nevertheless, we show evidence of an enhanced contribution of the largest copper smelter in the area, i.e., Caletones, to the burden of SOx in the Santiago basin, especially in the form of sulfate associated to fine particles (diameters < 2.5 mum), during CLs. Further, we speculate that the Caletones plume may trigger or promote secondary aerosol formation during CLs in the Santiago basin. (C) 2002 Elsevier Science Ltd. All rights reserved.

  • 77. Galmarini, S
    et al.
    Bianconi, R
    Klug, W
    Mikkelsen, T
    Addis, R
    Andronopoulos, S
    Astrup, P
    Baklanov, A
    Bartniki, J
    Bartzis, J C
    Bellasio, R
    Bompay, F
    Buckley, R
    Bouzom, M
    Champion, H
    D'Amours, R
    Davakis, E
    Eleveld, H
    Geertsema, G T
    Glaab, H
    Kolax, Michael
    SMHI, Research Department, Climate research - Rossby Centre.
    Ilvonen, M
    Manning, A
    Pechinger, U
    Persson, Christer
    SMHI, Research Department, Air quality.
    Polreich, E
    Potemski, S
    Prodanova, M
    Saltbones, J
    Slaper, H
    Sofiev, M A
    Syrakov, D
    Sorensen, J H
    Van der Auwera, L
    Valkama, I
    Zelazny, R
    Ensemble dispersion forecasting - Part I: concept, approach and indicators2004In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 38, no 28, p. 4607-4617Article in journal (Refereed)
    Abstract [en]

    The paper presents an approach to the treatment and analysis of long-range transport and dispersion model forecasts. Long-range is intended here as the space scale of the order of few thousands of kilometers known also as continental scale. The method is called multi-model ensemble dispersion and is based on the simultaneous analysis of several model simulations by means of ad-hoc statistical treatments and parameters. The models considered in this study are operational long-range transport and dispersion models used to support decision making in various countries in case of accidental releases of harmful volatile substances, in particular radionuclides to the atmosphere. The ensemble dispersion approach and indicators provide a way to reduce several model results to few concise representations that include an estimate of the models' agreement in predicting a specific scenario. The parameters proposed are particularly suited for long-range transport and dispersion models although they can also be applied to short-range dispersion and weather fields. (C) 2004 Elsevier Ltd. All rights reserved.

  • 78. Galmarini, S.
    et al.
    Bonnardot, F.
    Jones, A.
    Potempski, S.
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Martet, M.
    Multi-model vs. EPS-based ensemble atmospheric dispersion simulations: A quantitative assessment on the ETEX-1 tracer experiment case2010In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 44, no 29, p. 3558-3567Article in journal (Refereed)
    Abstract [en]

    Several techniques have been developed over the last decade for the ensemble treatment of atmospheric dispersion model predictions. Among them two have received most of the attention, the multi-model and the ensemble prediction system (EPS) modeling. The multi-model approach relies on model simulations produced by different atmospheric dispersion models using meteorological data from potentially different weather prediction systems. The EPS-based ensemble is generated by running a single atmospheric dispersion model with the ensemble weather prediction members. In the paper we compare both approaches with the help of statistical indicators, using the simulations performed for the ETEX-1 tracer experiment. Both ensembles are also evaluated against measurement data. Among the most relevant results is that the multi-model median and the mean of EPS-based ensemble produced the best results, hence we consider a combination of multi-model and EPS-based approaches as an interesting suggestion for further research. (C) 2010 Elsevier Ltd. All rights reserved.

  • 79. Geels, Camilla
    et al.
    Andersson, Camilla
    SMHI, Research Department, Air quality.
    Hanninen, Otto
    Lanso, Anne Sofie
    Schwarze, Per E.
    Skjoth, Carsten Ambelas
    Brandt, Jorgen
    Future Premature Mortality Due to O-3, Secondary Inorganic Aerosols and Primary PM in Europe - Sensitivity to Changes in Climate, Anthropogenic Emissions, Population and Building Stock2015In: International Journal of Environmental Research and Public Health, ISSN 1661-7827, E-ISSN 1660-4601, Vol. 12, no 3, p. 2837-2869Article in journal (Refereed)
    Abstract [en]

    Air pollution is an important environmental factor associated with health impacts in Europe and considerable resources are used to reduce exposure to air pollution through emission reductions. These reductions will have non-linear effects on exposure due, e.g., to interactions between climate and atmospheric chemistry. By using an integrated assessment model, we quantify the effect of changes in climate, emissions and population demography on exposure and health impacts in Europe. The sensitivity to the changes is assessed by investigating the differences between the decades 2000-2009, 2050-2059 and 2080-2089. We focus on the number of premature deaths related to atmospheric ozone, Secondary Inorganic Aerosols and primary PM. For the Nordic region we furthermore include a projection on how population exposure might develop due to changes in building stock with increased energy efficiency. Reductions in emissions cause a large significant decrease in mortality, while climate effects on chemistry and emissions only affects premature mortality by a few percent. Changes in population demography lead to a larger relative increase in chronic mortality than the relative increase in population. Finally, the projected changes in building stock and infiltration rates in the Nordic indicate that this factor may be very important for assessments of population exposure in the future.

  • 80. Genberg, J.
    et al.
    Hyder, M.
    Stenstrom, K.
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Simpson, D.
    Fors, E. O.
    Jonsson, J. A.
    Swietlicki, E.
    Source apportionment of carbonaceous aerosol in southern Sweden2011In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 11, no 22, p. 11387-11400Article in journal (Refereed)
    Abstract [en]

    A one-year study was performed at the Vavihill background station in southern Sweden to estimate the anthropogenic contribution to the carbonaceous aerosol. Weekly samples of the particulate matter PM10 were collected on quartz filters, and the amounts of organic carbon, elemental carbon, radiocarbon (C-14) and levoglucosan were measured. This approach enabled source apportionment of the total carbon in the PM10 fraction using the concentration ratios of the sources. The sources considered in this study were emissions from the combustion of fossil fuels and biomass, as well as biogenic sources. During the summer, the carbonaceous aerosol mass was dominated by compounds of biogenic origin (80 %), which are associated with biogenic primary and secondary organic aerosols. During the winter months, biomass combustion (32 %) and fossil fuel combustion (28 %) were the main contributors to the carbonaceous aerosol. Elemental carbon concentrations in winter were about twice as large as during summer, and can be attributed to biomass combustion, probably from domestic wood burning. The contribution of fossil fuels to elemental carbon was stable throughout the year, although the fossil contribution to organic carbon increased during the winter. Thus, the organic aerosol originated mainly from natural sources during the summer and from anthropogenic sources during the winter. The result of this source apportionment was compared with results from the EMEP MSC-W chemical transport model. The model and measurements were generally consistent for total atmospheric organic carbon, however, the contribution of the sources varied substantially. E.g. the biomass burning contributions of OC were underestimated by the model by a factor of 2.2 compared to the measurements.

  • 81. Genberg, J.
    et al.
    van der Gon, H. A. C. Denier
    Simpson, D.
    Swietlicki, E.
    Areskoug, H.
    Beddows, D.
    Ceburnis, D.
    Fiebig, M.
    Hansson, H. C.
    Harrison, R. M.
    Jennings, S. G.
    Saarikoski, S.
    Spindler, G.
    Visschedijk, A. J. H.
    Wiedensohler, A.
    Yttri, K. E.
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Light-absorbing carbon in Europe - measurement and modelling, with a focus on residential wood combustion emissions2013In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 13, no 17, p. 8719-8738Article in journal (Refereed)
    Abstract [en]

    The atmospheric concentration of elemental carbon (EC) in Europe during the six-year period 2005-2010 has been simulated with the EMEP MSC-W model. The model bias compared to EC measurements was less than 20% for most of the examined sites. The model results suggest that fossil fuel combustion is the dominant source of EC in most of Europe but that there are important contributions also from residential wood burning during the cold seasons and, during certain episodes, also from open biomass burning (wildfires and agricultural fires). The modelled contributions from open biomass fires to ground level concentrations of EC were small at the sites included in the present study, <3% of the long-term average of EC in PM10. The modelling of this EC source is subject to many uncertainties, and it was likely underestimated for some episodes. EC measurements and modelled EC were also compared to optical measurements of black carbon (BC). The relationships between EC and BC (as given by mass absorption cross section, MAC, values) differed widely between the sites, and the correlation between observed EC and BC is sometimes poor, making it difficult to compare results using the two techniques and limiting the comparability of BC measurements to model EC results. A new bottom-up emission inventory for carbonaceous aerosol from residential wood combustion has been applied. For some countries the new inventory has substantially different EC emissions compared to earlier estimates. For northern Europe the most significant changes are much lower emissions in Norway and higher emissions in neighbouring Sweden and Finland. For Norway and Sweden, comparisons to source-apportionment data from winter campaigns indicate that the new inventory may improve model-calculated EC from wood burning. Finally, three different model setups were tested with variable atmospheric lifetimes of EC in order to evaluate the model sensitivity to the assumptions regarding hygroscopicity and atmospheric ageing of EC. The standard ageing scheme leads to a rapid transformation of the emitted hydrophobic EC to hygroscopic particles, and generates similar results when assuming that all EC is aged at the point of emission. Assuming hydrophobic emissions and no ageing leads to higher EC concentrations. For the more remote sites, the observed EC concentration was in between the modelled EC using standard ageing and the scenario treating EC as hydrophobic. This could indicate too-rapid EC ageing in the model in relatively clean parts of the atmosphere.

  • 82.
    Gidhagen, Lars
    SMHI, Research Department, Air quality.
    COASTAL UPWELLING IN THE BALTIC SEA - SATELLITE AND INSITU MEASUREMENTS OF SEA-SURFACE TEMPERATURES INDICATING COASTAL UPWELLING1987In: Estuarine, Coastal and Shelf Science, ISSN 0272-7714, E-ISSN 1096-0015, Vol. 24, no 4, p. 449-462Article in journal (Refereed)
  • 83.
    Gidhagen, Lars
    et al.
    SMHI, Research Department, Air quality.
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    Lovenheim, Boel
    Johansson, Christer
    Modeling Effects of Climate Change on Air Quality and Population Exposure in Urban Planning Scenarios2012In: Advances in Meteorology, ISSN 1687-9309, E-ISSN 1687-9317, article id 240894Article in journal (Refereed)
    Abstract [en]

    We employ a nested system of global and regional climate models, linked to regional and urban air quality chemical transport models utilizing detailed inventories of present and future emissions, to study the relative impact of climate change and changing air pollutant emissions on air quality and population exposure in Stockholm, Sweden. We show that climate change only marginally affects air quality over the 20-year period studied. An exposure assessment reveals that the population of Stockholm can expect considerably lower NO2 exposure in the future, mainly due to reduced local NOx emissions. Ozone exposure will decrease only slightly, due to a combination of increased concentrations in the city centre and decreasing concentrations in the suburban areas. The increase in ozone concentration is a consequence of decreased local NOx emissions, which reduces the titration of the long-range transported ozone. Finally, we evaluate the consequences of a planned road transit project on future air quality in Stockholm. The construction of a very large bypass road (including one of the largest motorway road tunnels in Europe) will only marginally influence total population exposure, this since the improved air quality in the city centre will be complemented by deteriorated air quality in suburban, residential areas.

  • 84.
    Gidhagen, Lars
    et al.
    SMHI, Research Department, Air quality.
    Funquist, Lennart
    SMHI, Research Department, Oceanography.
    Murthy, Ray
    SMHI.
    Calculations of horizontal exchange coefficients using Eulerian time series current meter data from the Baltic Sea1986Report (Other academic)
  • 85.
    Gidhagen, Lars
    et al.
    SMHI, Research Department, Air quality.
    Johansson, C
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Foltescu, Valter
    SMHI.
    Urban scale modeling of particle number concentration in Stockholm2005In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 39, no 9, p. 1711-1725Article in journal (Refereed)
    Abstract [en]

    A three-dimensional dispersion model has been implemented over the urban area of Stockholm (35 x 35 km) to assess the spatial distribution of number concentrations of particles in the diameter range 3-400 nm. Typical number concentrations in the urban background of Stockholm is 10 000 cm(-3), while they are three times higher close to a major highway outside the city and seven times higher within a densely trafficked street canyon site in the city center. The model, which includes an aerosol module for calculating the particle number losses due to coagulation and dry deposition, has been run for a 10-day period. Model results compare well with measured data, both in levels and in temporal variability. Coagulation was found to be of little importance in terms of time averaged concentrations, contributing to losses of only a few percent as compared to inert particles, while dry deposition yield particle number losses of up to 25% in certain locations. Episodic losses of up to 10% due to coagulation and 50% due to deposition, are found some kilometers downwind of major roads, rising in connection with low wind speed and suppressed turbulent mixing. Removal due to coagulation and deposition will thus be more significant for the simulation of extreme particle number concentrations during peak episodes. The study shows that dispersion models with proper aerosol dynamics included may be used to assess particle number concentrations in Stockholm, where ultrafine particles principally originate from traffic emissions. Emission factors may be determined from roadside measurements, but ambient temperature must be considered, as it has a strong influence on particle number emissions from vehicles. (c) 2005 Elsevier Ltd. All rights reserved.

  • 86.
    Gidhagen, Lars
    et al.
    SMHI, Research Department, Air quality.
    Johansson, C
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Olivares, G
    Simulation of NOx and ultrafine particles in a street canyon in Stockholm, Sweden2004In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 38, no 14, p. 2029-2044Article in journal (Refereed)
    Abstract [en]

    A computational fluid dynamic (CFD) model has been used to assess the concentrations of NO, and particle number in a street canyon in Stockholm with a high traffic volume. Comparisons of a simulated 11-week long time series of NOx with measurements (both sides of the street, urban background excluded) show good agreement, especially if emissions are distributed to be three times higher along the side of the street where the traffic is uphill, as compared to the downhill side. The simulation of number concentrations of inert particles indicates a similar asymmetry in emissions. A month-long measurement of particle size distribution (7-450 nm) at street level indicates that the ratio of nucleation size mode particle (7-20 nm) to total particle number (7-450 nm) is decreasing for increased particle surface area. Given the strong dominance of the locally generated particles over the urban background, this is interpreted as a local change in the size distribution. The results of a monodisperse aerosol dynamic model, coupled to the CFD model that simulates also the turbulence generated by vehicle movements, show that coagulation and deposition may reduce total particle inside the canyon with approximately 30% during low wind speeds. Most of the removal occurs shortly after emission, before the particles reach the leeward curb-side. Losses between the leeward curb-side and other locations in the street, e.g. roof levels, is estimated to be smaller, less than 10%. Coagulation is the dominating removal process under low wind speed conditions and deposition for higher wind speeds, the summed removal being smaller for high wind velocities. Deposition is enhanced over the road surface due to the velocities generated by vehicle movements. Although coagulation and deposition removal is most effective on the smallest ultrafine particles, this effect is not sufficient to explain the observed change in size distribution. It is suggested that also the formation of particles in the exhaust plumes is influenced by a larger particle surface area in the ambient air. (C) 2004 Elsevier Ltd. All rights reserved.

  • 87.
    Gidhagen, Lars
    et al.
    SMHI, Research Department, Air quality.
    Johansson, C
    Omstedt, Gunnar
    SMHI, Research Department, Air quality.
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Olivares, G
    Model simulations of NOx and ultrafine particles close to a Swedish highway2004In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 38, no 24, p. 6730-6740Article in journal (Refereed)
    Abstract [en]

    Based on the results from a 6-week monitoring campaign in an area close to a major highway north of Stockholm, Sweden, NOx emission factors representative for vehicle speeds of 100-120 km per h were determined to 0.61 g/veh-km for light duty and to 7.1 g/veh,km for heavy duty vehicles. The corresponding factors for particle number were 1.4 x 10(14) and 52 x 10(14) particles/veh,km, determined for an ambient temperature interval of +7 to +17 degreesC. The removal effects of coagulation and dry deposition on total number concentrations were assessed by numerical model simulations. Velocity and turbulence fields, including those produced by the vehicles, were simulated in a Computational Fluid Dynamics (CFD) model. Coagulation was found to be of little importance over the first 100 m downwind of the highway. The high friction velocities over the road surface created by vehicle movements enhanced deposition locally, contributing to the removal of approximately 10% of the particles originally emitted. Beyond a point 10 m downwind of the highway the removal rate was low and the ultrafine particles were almost inert while being advected over the next hundred meters. As a consequence, it seems reasonable to use monitored data from stations close to highways to estimate emission factors for particle number, assuming that the particles are inert. Those "effective" emission factors should be applicable for urban models with a larger spatial resolution.

  • 88.
    Gidhagen, Lars
    et al.
    SMHI, Research Department, Air quality.
    Johansson, C
    Strom, J
    Kristensson, A
    Swietlicki, E
    Pirjola, L
    Hansson, H C
    Model simulation of ultrafine particles inside a road tunnel2003In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 37, no 15, p. 2023-2036Article in journal (Refereed)
    Abstract [en]

    A monodispersive aerosol dynamic model, coupled to a 3D hydrodynamical grid model, has been used to study the dynamics of ultrafine particles inside a road tunnel in Stockholm, Sweden. The model results were compared to measured data of particle number concentrations, traffic intensity and tunnel ventilation rate. Coagulation and depositional losses to the tunnel walls were shown to be important processes during traffic peak hours, together contributing to losses of 77% of the particles smaller than 10nm and 41% of the particles of size 10-29nm. Particle growth due to water uptake or the presence of a micron-sized, resuspended particle fraction did not have any significant effect on the number of particles lost due to coagulation. Model simulation of particle number concentration response to temporal variations in traffic flow showed that constant emission factors could be used to reproduce the concentration variations of the particles larger than 29nm, while vehicle-speed-dependent factors are suggested to reproduce the variation of the smallest fractions. The emission factors for particle number concentrations estimated from the model simulation are in general higher and show a larger contribution from light-duty vehicles than what has been reported from a tunnel in California. The model study shows that combined measurements and model simulations in road tunnels can be used to improve the determinations of vehicle emission factors for ultrafine particles under realistic driving conditions. (C) 2003 Elsevier Science Ltd. All rights reserved.

  • 89.
    Gidhagen, Lars
    et al.
    SMHI, Research Department, Air quality.
    Johansson, Christer
    Institutionen för tillämpad miljövetenskap (ITM), Stockholms universitet.
    Törnquist, L.
    NORDIC - A database for evaluation of dispersion models on the local, urban and regional scale2004Report (Other academic)
  • 90.
    Gidhagen, Lars
    et al.
    SMHI, Research Department, Air quality.
    Johansson, H.
    Omstedt, Gunnar
    SMHI, Research Department, Air quality.
    SIMAIR-Evaluation tool for meeting the EU directive on air pollution limits2009In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 43, no 5, p. 1029-1036Article in journal (Refereed)
    Abstract [en]

    Almost all Swedish cities need to determine air pollution levels especially PM10-close to major streets. SIMAIR is an internet tool that can be used by all Swedish municipalities to assess PM10, NO(2), CO and benzene levels and how they compare to the EU directive. SIMAIR is delivered to the municipalities with all required input data pre-loaded and is meant to be used prior to decisions if and where, monitoring campaigns are required. The system includes a road and vehicle database with emission factors and a model to calculate non tailpipe PM10 emissions. Regional and urban background contributions are pre-calculated and stored as hourly values oil a 1 x 1 km(2) grid. The local contribution is calculated by the user, selecting either an open road or a street canyon environment. A comparison between measured and simulated concentrations in four street locations shows that SIMAIR is able to Calculate statistics of yearly mean values, 90-percentile and 98-percentile daily mean values and the number of days exceeding the limit value that are well within +/- 50% that EU requires for model estimates of yearly mean values. In comparison, all Values except one are within +/- 25% which is the quality objective for fixed measurements according to the EU directive. The SIMAIR model system is also able to separate the percentual contribution of the long-range transport from Outside the city, the city contribution and the local contribution from the traffic of an individual street. (C) 2008 Elsevier Ltd. All rights reserved.

  • 91.
    Gidhagen, Lars
    et al.
    SMHI, Research Department, Air quality.
    Kahelin, H
    Schmidt-Thome, P
    Johansson, C
    Anthropogenic and natural levels of arsenic in PM10 in Central and Northern Chile2002In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 36, no 23, p. 3803-3817Article in journal (Refereed)
    Abstract [en]

    A few copper and gold smelters in Chile are behind a large fraction of global arsenic emissions, raising concerns for increased concentrations of arsenic in PM10 in Central and Northern Chile. This concern is amplified by the fact that Northern Chile soils and rivers in general are characterized by a high arsenic content. A monitoring and modeling study has been performed to quantify the regional impact of the smelter emissions. Measured atmospheric arsenic concentrations from 2.4 to 30.7 ng m(-3) were found at seven rural stations, located tens to hundreds of kilometers away from the nearest smelter. Analyses of topsoil and subsoil samples taken from PM 10 monitoring stations revealed levels up to 291 mg kg(-1), the highest values found in the northern Atacama desert in Chile. An absolute principal component analysis of selected trace elements in PM10 shows that the regional impact of anthropogenic smelter emissions on airborne arsenic concentrations is more important than the effect of soil dust resuspension. The dominance of the smelter emissions is larger in Central Chile than in the northern parts. The impact of resuspended soil dust on airborne arsenic levels in rural areas was estimated not to exceed 5 ng m(-3). The model calculations support the dominant role of anthropogenic emissions and give spatial and temporal variations in atmospheric concentrations consistent with the monitored levels at five of the seven stations. At two of the northernmost stations indications were found of unidentified sources other than the smelters and the resuspended soil dust, contributing to about 5 ng m(-3) of total arsenic levels. The study confirms that a strong control or elimination of arsenic emissions from the smelters would lead to arsenic in PM10 levels in Northern and Central Chile comparable to non-polluted areas in other countries. (C) 2002 Elsevier Science Ltd. All rights reserved.

  • 92.
    Gidhagen, Lars
    et al.
    SMHI, Research Department, Air quality.
    Omstedt, Gunnar
    SMHI, Research Department, Air quality.
    Pershagen, Goran
    Willers, Saskia
    Bellander, Tom
    High-resolution modeling of residential outdoor particulate levels in Sweden2013In: Journal of Exposure Science and Environmental Epidemiology, ISSN 1559-0631, E-ISSN 1559-064X, Vol. 23, no 3, p. 306-314Article in journal (Refereed)
    Abstract [en]

    Large-scale exposure assessments that include both between- and within-city differences in air pollution levels are lacking. The objective of this study was to model long-term particle exposure for the whole of Sweden, separating long-range transport from local sources, which were further separated into combustion and road dust. Annual regional, urban and local traffic PM exposure contributions were modeled for 26,000 addresses from a national survey, using a European scale model, an urban model and a local traffic model. Total PM10 was overall dominated by the regional contribution, ranging from 3.5 mu g/m(3) (northernmost) to 13.5 mu g/m(3) (southernmost). Local traffic and urban sources contributed nationally on average to 16% of total PM10, but for urban populations this contribution was larger (for Stockholm around 30%). Generalized to the Swedish adult population, the average residential exposure contributions from regional, urban and local traffic PM10 were 10.2, 1.3 and 0.2 mu g/m(3), respectively. Corresponding exposure to PM, was 5.1, 0.5 and 0.03 mu g/m(3), respectively. Long-range transport dominates average Swedish residential PM1 and PM10 levels, but for urban populations the contributions from urban and local traffic sources are important and may even dominate for residences close to heavily trafficked roads. The study shows the importance of considering both national and city-scale gradients. The approach to exposure modeling at home addresses of a Swedish cohort includes both the regional scale and the urban and local traffic contributions to total PM exposure. With this we can resolve both between- and within-city gradients in national exposure assessments. The within-city exposure is further divided into a submicron (combustion) and a supermicron (road dust generated by studded tires) part. This gives new possibilities to study health impacts of different particles generated in Scandinavian cities. Journal of Exposure Science and Environmental Epidemiology (2013) 23, 306-314; doi:10.1038/jes.2012.122; published online 23 January 2013

  • 93. Gramsch, Ernesto
    et al.
    Gidhagen, Lars
    SMHI, Research Department, Air quality.
    Wahlin, Peter
    Oyola, Pedro
    Moreno, Francisco
    Predominance of soot-mode ultrafine particles in Santiago de Chile: Possible sources2009In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 43, no 14, p. 2260-2267Article in journal (Refereed)
    Abstract [en]

    A monitoring campaign was performed in Santiago de Chile during a winter month of 2003 and 2006 (July) using several instruments to measure the size distribution of particulate material. For the first time, the size distribution of ultrafine particles was measured in Santiago, and an estimation of its sources was done by analyzing its temporal variation. The study was performed in three sites: one of them is located in the eastern part of Santiago, a sector with low particle concentration and about 100 m from a busy street. The other site is located in the western part, which is the sector that has the highest concentration of fine and coarse particle matter during winter, also located far from a street. The third site is located within 5 in from the busiest street in Santiago. In all stations traffic is the dominating source for fine and ultrafine particles and the size distribution is peaked towards 60-100 nm (soot mode). Only in the site near the street, it is possible to see a clear peak towards smaller sizes (10-30 nm). The size distribution measurements presented here indicate that aerosol dynamics play a more important role for the Santiago case as compared to cleaner cities in Europe. Changes in the particle size during different hours of the day reflect both variations in meteorological mixing conditions as well as effects of aerosol dynamic processes such as coagulation, condensation and dry deposition. A relative increase in the number of the larger ultrafine particles (d >= 70 nm), as compared to the number of smaller particles (d < 70 nm) correlated with wind speed is an indication of pollution transport with aged particles from other parts of the city. (C) 2009 Elsevier Ltd. All rights reserved.

  • 94. Grote, Ruediger
    et al.
    Samson, Roeland
    Alonso, Rocio
    Amorim, Jorge Humberto
    SMHI, Research Department, Air quality.
    Carinanos, Paloma
    Churkina, Galina
    Fares, Silvano
    Le Thiec, Didier
    Niinemets, Ulo
    Mikkelsen, Teis Norgaard
    Paoletti, Elena
    Tiwary, Abhishek
    Calfapietra, Carlo
    Functional traits of urban trees: air pollution mitigation potential2016In: Frontiers in Ecology and the Environment, ISSN 1540-9295, E-ISSN 1540-9309, Vol. 14, no 10, p. 543-550Article in journal (Refereed)
  • 95. Haapanala, Paivi
    et al.
    Raisanen, Petri
    Kahnert, Michael
    SMHI, Research Department, Air quality.
    Nousiainen, Timo
    Sensitivity of the shortwave radiative effect of dust on particle shape: Comparison of spheres and spheroids2012In: Journal of Geophysical Research - Atmospheres, ISSN 2169-897X, E-ISSN 2169-8996, Vol. 117, article id D08201Article in journal (Refereed)
    Abstract [en]

    The sensitivity of direct shortwave radiative effects of dust (DRE) to assumed particle shape is investigated. Radiative transfer simulations are conducted using optical properties of either spheres, mass-equivalent spheroids (mass-conserving case), or (mass-equivalent) spheroids whose number concentration is modified so that they have the same midvisible optical thickness (tau(545 nm)) as spheres (tau-conserving case). The impact of particle shape on DRE is investigated for different dust particle effective radii, optical thickness of the dust cloud, solar zenith angle, and spectral surface albedo (ocean, grass, and desert). It is found that the influence of particle shape on the DRE is strongest over ocean. It also depends very strongly on the shape distribution of spheroids used, to a degree that the results for two distributions of spheroids may deviate more from each other than from those for spheres. Finally, the effects of nonsphericity largely depend on whether the mass- or tau-conserving case is considered. For example, when using a shape distribution of spheroids recommended in a recent study for approximating the single-scattering properties of dust, the DRE at the surface differs at most 5% from that from spherical particles in the mass-conserving case. This stems from compensating nonsphericity effects on optical thickness, asymmetry parameter, and single-scattering albedo. However, in the tau-conserving case, the negative DRE at the surface can be up to 15% weaker for spheroids than spheres.

  • 96. Haapanala, Paivi
    et al.
    Raisanen, Petri
    McFarquhar, Greg M.
    Tiira, Jussi
    Macke, Andreas
    Kahnert, Michael
    SMHI, Research Department, Air quality.
    DeVore, John
    Nousiainen, Timo
    Disk and circumsolar radiances in the presence of ice clouds2017In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 17, no 11, p. 6865-6882Article in journal (Refereed)
  • 97. Han, Z.
    et al.
    Sakurai, T.
    Ueda, H.
    Carmichael, G. R.
    Streets, D.
    Hayami, H.
    Wang, Z.
    Holloway, T.
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    Hozumi, Y.
    Park, S. U.
    Kajino, M.
    Sartelet, K.
    Fung, C.
    Bennet, Cecilia
    SMHI, Research Department, Air quality.
    Thongboonchoo, N.
    Tang, Y.
    Chang, A.
    Matsuda, K.
    Amann, M.
    MICS-Asia II: Model intercomparison and evaluation of ozone and relevant species2008In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 42, no 15, p. 3491-3509Article in journal (Refereed)
    Abstract [en]

    Eight regional Eulerian chemical transport models (CTMs) are compared with each other and with an extensive set of observations including ground-level concentrations from EANET, ozone soundings from JMA and vertical profiles from the TRACE-P experiment to evaluate the models' abilities in simulating O(3) and relevant species (SO(2), NO, NO(2), HNO(3) and PAN) in the troposphere of East Asia and to look for similarities and differences among model performances. Statistical analysis is conducted to help estimate the consistency and discrepancy between model simulation and observation in terms of various species, seasons, locations, as well as attitude ranges. In general, all models show a good skill of simulating SO(2) for both ground level and the lower troposphere, although two of the eight models systematically overpredict SO(2) concentration. The model skills for O(3) vary largely with region and season. For ground-level O(3), model results are best correlated with observations in July 2001. Comparing with O(3) soundings measured in the afternoon reveals the best consistency among models in March 2001 and the largest disparity in O(3) magnitude in July 2001, although most models produce the best correlation in July as well. In terms of the statistics for the four flights of TRACE-P experiment, most models appear to be able to accurately capture the variability in the lower troposphere. The model performances for NO(x) are relatively poor, with lower correlation and with almost all models tending to underpredict NO(x) levels, due to larger uncertainties in either emission estimates or complex chemical mechanism represented. All models exhibit larger RMSE at altitudes < 2 km than 2-5.5 kin, mainly due to a consistent tendency of these models towards underprediction of the magnitude of intense plumes that often originate from near surface. Relatively lower correlation at altitudes 2-5.5 km may be attributed to the models' limitation in representing convection or potential chemical processes. Most of the key features in species distribution have been consistently reproduced by the participating models, such as the O(3) enhancement in the western Pacific Ocean in March and in northeast Asia in July, respectively, although the absolute model values may differ considerably from each other. Large differences are found among models in the southern parts of the domain for all the four periods, including southern China and northern parts of some Southeast Asia countries where the behaviors of chemical components and the ability of these models are still not clearly known because of a lack of observational databases. (C) 2007 Elsevier Ltd. All rights reserved.

  • 98. Hayami, Hiroshi
    et al.
    Sakurai, T.
    Han, Z.
    Ueda, H.
    Carmichael, G. R.
    Streets, D.
    Holloway, T.
    Wang, Z.
    Thongboonchoo, N.
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    Bennet, Cecilia
    SMHI, Research Department, Air quality.
    Fung, C.
    Chang, A.
    Park, S. U.
    Kajino, M.
    Sartelet, K.
    Matsuda, K.
    Amann, M.
    MICS-Asia II: Model intercomparison and evaluation of particulate sulfate, nitrate and ammonium2008In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 42, no 15, p. 3510-3527Article in journal (Refereed)
    Abstract [en]

    Eight chemical transport models participate in a model intercomparison study for East Asia, MICS-Asia II. This paper analyzes calculated results for particulate matter of sulfate, nitrate and ammonium through comparisons with each other and with monthly measurements at EANET (the acid deposition monitoring network in East Asia) and daily measurements at Fukue, Japan. To the EANET measurements, model ensemble means better agree with model individual results for sulfate and total ammonium, although total nitrate is consistently and considerably underestimated. To measurements at Fukue, the models show better agreement than for the EANET measurements. This is likely because Fukue is centered in many of the model domains, whereas the EANET stations are mostly in Southeast Asia and Russia. Moreover, it would be important that Fukue is in Northeast Asia, where the emission inventory is more reliable than Southeast Asia. The model-model comparisons are made in view of the total amount in the atmosphere, vertical profile, coefficient of variation in surface concentrations, and transformation changes with distance. All the models show reasonable tendencies in vertical profiles and composition ratios. However, total amounts in the atmosphere are discrepant among the models. The consistency of the total amount in the atmosphere would influence source-receptor analysis. It seems that model results would be consistent, if the models take into account the primitive processes like emission, advection/diffusion, chemical transformation and dry/wet deposition, no matter the processes are modeled simply or comprehensively. Through the comparison study, we learned that it would be difficult to find any problems from one comparison (model-observation comparison with one data or many but at one station or in a short period). Modelers tend to examine model performances only from model-observation comparisons. However, taking budget in a certain or whole model domain would be important, before the models are applied to source-receptor analysis. (C) 2007 Elsevier Ltd. All rights reserved.

  • 99. Hedberg, E
    et al.
    Gidhagen, Lars
    SMHI, Research Department, Air quality.
    Johansson, C
    Source contributions to PM10 and arsenic concentrations in Central Chile using positive matrix factorization2005In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 39, no 3, p. 549-561Article in journal (Refereed)
    Abstract [en]

    Sampling of particles (PM10) was conducted during a one-year period at two rural sites in Central Chile, Quillota and Linares. The samples were analyzed for elemental composition. The data sets have undergone source-recepior analyses in order to estimate the sources and their abundance's in the PM10 size fraction. by using the factor analytical method positive matrix factorization (PMF). The analysis showed that PM10 was dominated by soil resuspension at both sites during the summer months, while during winter traffic dominated the particle mass at Quillota and local wood burning dominated the particle mass at Linares. Two copper smelters impacted the Quillota station, and contributed to 10% and 16% of PM10 as an average during summer and winter. respectively. One smelter impacted Linares by 8% and 19% of PM10 in the summer and winter, respectively. For arsenic the two smelters accounted for 87% of the monitored arsenic levels at Quillota and at Linares one smelter contributed with 72% of the measured mass. In comparison with PMF, the use of a dispersion model tended to overestimate the smelter contribution to arsenic levels at both sites. The robustness of the PMF model was tested by using randomly reduced data sets, where 85%, 70%, 50% and 33% of the samples were included. In this way the ability of the model to reconstruct the sources initially found by the original data set could be tested. On average for all sources the relative standard deviation increased from 7% to 25% for the variables identifying the sources, when decreasing the data set from 85% to 33% of the samples, indicating that the solution initially found was very stable to begin with. But it was also noted that sources due to industrial or combustion processes were more sensitive for the size of the data set, compared to the natural sources as local soil and sea spray sources. (C) 2004 Elsevier Ltd. All rights reserved.

  • 100. Hiemstra, J.A.
    et al.
    Saaroni, H.
    Amorim, Jorge Humberto
    SMHI, Research Department, Air quality.
    The Urban Heat Island: Thermal Comfort and the Role of Urban Greening2017In: The Urban Forest - Cultivating Green Infrastructure for People and the Environment / [ed] D. Pearlmutter, C. Calfapietra, R. Samson, L. O'Brien, S.K. Ostoić, G. Sanesi, R.A. del Amo, Springer International Publishing , 2017, p. 7-19Chapter in book (Refereed)
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