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  • 1.
    Andersson-Sköld, Yvonne
    et al.
    Melica.
    Janhäll, Sara
    IVL.
    Simulations of ozone formation from different emission sources in Sweden1995In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 85, no 4, p. 2045-2050Article in journal (Refereed)
    Abstract [en]

    An emission inventory concerning volatile organic compounds (VOC) and their emission profile linked to their sources in Sweden has been undertaken. The inventory has been used in model simulations to predict the ozone formation from different emission source categories in Sweden. The studies have been carried out using the IVL photochemical trajectory model for two types of air masses which describes clean and polluted air. In Sweden mobile sources contribute to 45 % by mass of the total national VOC emissions, 58 % of the NOx emissions and to at least 43 % of the ozone formation from national sources. In general, the ozone formation in Sweden is more dependent and sensitive to emissions of NOx rather than VOC

  • 2.
    Andersson-Sköld, Yvonne
    et al.
    COWI AB.
    Thorson, Sofia
    Göteborgs Universitet.
    Rayner, David
    Göteborgs Universitet.
    Lindberg, Fredrik
    Göteborgs Universitet.
    Janhäll, Sara
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Jonsson, Anna C
    Linköpings Universitet.
    Moback, Ulf
    Göteborgs stad.
    Bergman, Ramona
    SGI.
    Granberg, Mikael
    Karlstad Universitet.
    An integrated method for assessing climate related risks and adaptation alternatives in urban areas2015In: Climate Risk Management, E-ISSN 2212-0963, Vol. 7, p. 31-50Article in journal (Refereed)
    Abstract [en]

    The urban environment is a complex structure with interlinked social, ecological and technical structures. Global warming is expected to have a broad variety of impacts, which will add to the complexity. Climate changes will force adaptation, to reduce climate-related risks. Adaptation measures can address one aspect at the time, or aim for a holistic approach to avoid maladaptation. This paper presents a systematic, integrated approach for assessing alternatives for reducing the risks of heat waves, flooding and air pollution in urban settings, with the aim of reducing the risk of maladaptation.

    The study includes strategies covering different spatial scales, and both the current climate situation and the climate predicted under climate change scenarios. The adaptation strategies investigated included increasing vegetation; selecting density, height and colour of buildings; and retreat or resist (defend) against sea-level rise. Their effectiveness was assessed with regard to not only flooding, heat stress and air quality but also with regard to resource use, emissions to air (incl. GHG), soil and water, and people’s perceptions and vulnerability. The effectiveness of the strategies were ranked on a common scale (from −3 to 3) in an integrated assessment. Integrated assessments are recommended, as they help identify the most sustainable solutions, but to reduce the risk of maladaptation they require experts from a variety of disciplines.

    The most generally applicable recommendation, derived from the integrated assessment here, taking into account both expertise from different municipal departments, literature surveys, life cycle assessments and publics perceptions, is to increase the urban greenery, as it contributes to several positive aspects such as heat stress mitigation, air quality improvement, effective storm-water and flood-risk management, and it has several positive social impacts. The most favourable alternative was compact, mid-rise, light coloured building design with large parks/green areas and trees near buildings.

  • 3.
    Aretun, Åsa
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Mobility, actors and planning processes.
    Berg, Jessica
    Swedish National Road and Transport Research Institute, Society, environment and transport, Mobility, actors and planning processes.
    Henriksson, Malin
    Swedish National Road and Transport Research Institute, Society, environment and transport, Mobility, actors and planning processes.
    Henriksson, Per
    Swedish National Road and Transport Research Institute, Society, environment and transport, Mobility, actors and planning processes.
    Ihlström, Jonas
    Swedish National Road and Transport Research Institute, Traffic and road users, Human Factors in the Transport System.
    Janhäll, Sara
    RISE.
    Eric, Sjögren
    Cykelpoolen i Sverige AB.
    Silvander, Therese
    Energikontor Norra Småland.
    GoMate – Diversifierad elfordonspool för den förtätade staden: slutrapport2019Report (Other academic)
    Abstract [en]

    In the GoMate project, EV sharing services has been tested in two residential areas located in the central city of Jönköping; services consisting of e-bikes, e-cargo bikes and e-cars. The aim of the project has been to investigate whether and to what extent EV sharing services can contribute to reduced car use in favor of the use of more sustainable mobility solutions. The results show that a diversified EV club has the potential to reduce car use. It is mainly the e-bike that replaces car trips for everyday travel, which in the long term can reduce car holdings in favor of the use of e-car services for occasional travel.

    However, if the potential is to be realized, price and business models are required for these services that stimulate reduced car use, considered as a process that can be expected to occur gradually over time. Such a process also needs to be supported by policy instruments and measures that limit car use in central city areas.

    If the potential is to be realized, the services also need to be scaled up considerably with respect to the number of vehicles per apartment. Although there was a relatively large EV club with a total of 17 (of which 15 were bicycles) vehicles for 160 households, which were tested in the project, it only had the capacity to supply a very small proportion of the residents' total travel, and with very little effects regarding reduction in energy use and carbon emissions.

  • 4.
    Björklund, Gunilla
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Mobility, actors and planning processes.
    Forward, Sonja
    Swedish National Road and Transport Research Institute, Society, environment and transport, Mobility, actors and planning processes.
    Janhäll, Sara
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Stave, Christina
    Swedish National Road and Transport Research Institute, Traffic and road users, Driver and vehicle.
    Samspel i trafiken: formella och informella regler bland cyklister2017Report (Other academic)
    Abstract [en]

    Our understanding of cyclists’ behaviour in relation to rules and regulations are rather poor and the same applies to cyclists’ interaction with other road users. The purpose of this project was therefore to explore cyclists’ knowledge of traffic rules but also what determine their own compliance or noncompliance. Participants in the study were 612 people between 18 and 74 years from Gothenburg, Linköping and Stockholm and were recruited through a web panel. A survey was used which asked them about their background, view of themselves as cyclists, own self-compliance, view of others’ compliance, knowledge of rules and various factors that determine their intention to break the rules.

    The results from the study showed that the participants’ regular knowledge was relatively good, at least in terms of behaviours that are prohibited. The participants who thought that a certain behaviour was forbidden also replied that they did this to a lesser extent. Cyclists who stated that they would like to arrive as soon as possible tended to choose more flexible routes (e.g. bike across pedestrian crossings, pavements and roads mainly used by vehicles), whether permitted or not. To a greater extent they also stated that they did not always stop at red lights or at stop signs. Cycle crossings, junctions, pedestrian crossings and pavements were used as examples of places/situations where the rules were considered unclear. Perceived behavioural control and attitude influenced the intention to behave according to three hypothetical scenarios which described how other road users had to break or swerve in order to avoid an accident with the cyclist. This meant that those who intended to behave in the manner indicated believed that it was easy and rather harmless, but also that it was both right and good. However, the most important factor was if they had performed the behaviour in the past, which in turn may have reinforced this view, that is if nothing serious had happened.

  • 5.
    Carlson, Annelie
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Janhäll, Sara
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Hammarström, Ulf
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Utvärdering PHEM-modellen: En förstudie2013Report (Other academic)
    Abstract [en]

    The Swedish Transport Administration has stated that there is a need to develop the use of micro simulation models of fuel use and emissions of traffic that are used for transport planning. The aim of the project is to perform an evaluation of PHEM model to investigate conditions, opportunities and barriers to use it in transport planning. The following aspects have been assessed: License agreements, costs, rights, property issues; User friendliness; Content and calculation capabilities; Adjustment and development possibilities; Validation. Furthermore, simulation tests have been performed where fuel consumption and emissions of nitrogen oxide, nitrogen monoxide, carbon monoxide, hydrocarbons, particulate mass and particle number has been calculated for roads with different road classes and for additional emissions and fuel use due to a vehicle stop. PHEM model is found to be relatively user-friendly, and with great opportunities to customize calculations. This makes the model complex, therefore it is recommended to start using PHEM with a short introductory course, even for used modellers. A conclusion of the evaluation is a recommendation to use PHEM for transport modelling. The database underlying the engine maps is constantly updated leading to more reliable emission calculations. The possibility to get a greater coherence in the calculations of the exhaust emissions of the different models that the Transport Administration advocate is also improved, which is a positive development. There are, also, some development possibilities that should be considered.

  • 6.
    Denby, Bruce R.
    et al.
    The Norwegian Meteorological Institute (MET).
    Ketzel, M.
    Aarhus University.
    Ellermann, T.
    Aarhus University.
    Stojiljkovic, A.
    Nordic Envicon Oy.
    Kupiainen, K.
    Nordic Envicon Oy.
    Niemi, J. V.
    Helsinki Region Environmental Services Authority (HSY).
    Norman, M.
    Environment and Health Protection Administration of the City of Stockholm.
    Johansson, C.
    Stockholm University,.
    Gustafsson, Mats
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Blomqvist, Göran
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Janhäll, Sara
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Sundvor, I.
    The Norwegian Institute for Air Research (NILU).
    Road salt emissions: A comparison of measurements and modelling using the NORTRIP road dust emission model2016In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 141, p. 508-522Article in journal (Refereed)
    Abstract [en]

    De-icing of road surfaces is necessary in many countries during winter to improve vehicle traction. Large amounts of salt, most often sodium chloride, are applied every year. Most of this salt is removed through drainage or traffic spray processes but a certain amount may be suspended, after drying of the road surface, into the air and will contribute to the concentration of particulate matter. Though some measurements of salt concentrations are available near roads, the link between road maintenance salting activities and observed concentrations of salt in ambient air is yet to be quantified.

    In this study the NORTRIP road dust emission model, which estimates the emissions of both dust and salt from the road surface, is applied at five sites in four Nordic countries for ten separate winter periods where daily mean ambient air measurements of salt concentrations are available. The model is capable of reproducing many of the salt emission episodes, both in time and intensity, but also fails on other occasions.

    The observed mean concentration of salt in PM10, over all ten datasets, is 4.2 μg/m3 and the modelled mean is 2.8 μg/m3, giving a fractional bias of −0.38. The RMSE of the mean concentrations, over all 10 datasets, is 2.9 μg/m3 with an average R2 of 0.28. The mean concentration of salt is similar to the mean exhaust contribution during the winter periods of 2.6 μg/m3. The contribution of salt to the kerbside winter mean PM10 concentration is estimated to increase by 4.1 ± 3.4 μg/m3 for every kg/m2 of salt applied on the road surface during the winter season. Additional sensitivity studies showed that the accurate logging of salt applications is a prerequisite for predicting salt emissions, as well as good quality data on precipitation. It also highlights the need for more simultaneous measurements of salt loading together with ambient air concentrations to help improve model parameterisations of salt and moisture removal processes.

  • 7.
    Gaita, Samuel M.
    et al.
    Göteborgs Universitet.
    Boman, Johan
    Göteborgs Universitet.
    Gatari, Michael J.
    University of Nairobi.
    Pettersson, Jan B.C.
    Göteborgs Universitet.
    Janhäll, Sara
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Source apportionment and seasonal variation of PM2.5 in a Sub-Sahara African city: Nairobi, Kenya2014In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 14, no 18, p. 9977-9991Article in journal (Refereed)
    Abstract [en]

    Sources of airborne particulate matter and their seasonal variation in urban areas in Sub-Saharan Africa are poorly understood due to lack of long-term measurement data. In view of this, filter samples of airborne particulate matter (particle diameter ≤2.5 μm, PM2.5) were collected between May 2008 and April 2010 at two sites (urban background site and suburban site) within the Nairobi metropolitan area. A total of 780 samples were collected and analyzed for particulate mass, black carbon (BC) and 13 trace elements.

    The average PM2.5 concentration at the urban background site was 21±9.5 μg m−3, whereas the concentration at the suburban site was 13±7.3 μg m−3. The daily PM2.5 concentrations exceeded 25 μg m−3 (the World Health Organization 24 h guideline value) on 29% of the days at the urban background site and 7% of the days at the suburban site. At both sites, BC, Fe, S and Cl accounted for approximately 80% of all detected elements. Positive matrix factorization analysis identified five source factors that contribute to PM2.5 in Nairobi, namely traffic, mineral dust, industry, combustion and a mixed factor (composed of biomass burning, secondary aerosol and aged sea salt).

    Mineral dust and traffic factors were related to approximately 74% of PM2.5. The identified source factors exhibited seasonal variation, apart from the traffic factor, which was prominently consistent throughout the sampling period. Weekly variations were observed in all factors, with weekdays having higher concentrations than weekends. The results provide information that can be exploited for policy formulation and mitigation strategies to control air pollution in Sub-Saharan African cities.

  • 8.
    Gustafsson, Mats
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Abbasi, Saeed
    KTH.
    Blomqvist, Göran
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Cha, Yingying
    KTH.
    Gudmundsson, Anders
    Lund University.
    Janhäll, Sara
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Johansson, Christer
    SLB-analys and Stockholm University.
    Norman, Michael
    SLB-analys.
    Olofsson, Ulf
    KTH.
    Particles in road and railroad tunnel air: sources, properties and abatement measures2016Report (Other academic)
    Abstract [en]

    High levels of air pollution are a common problem in both road and railroad tunnels. Sources and emission processes however differ significantly, as reflected by aerosols physical and chemical properties. As particle concentrations and properties affect exposure of and health effects for people on platforms and in vehicles, effective ways to reduce emissions and exposure are important. This study aims to improve the knowledge of the differences between PM10 in the rail and road tunnel environments, their sources and the possibilities to address problems with high particulate levels. Measurement campaigns were carried out at Arlanda Central, a railroad tunnel station below Arlanda airport and in Söderleden road tunnel, a road tunnel in central Stockholm.

    The results show large differences in concentration levels, size distributions and in composition of the particles. The railroad tunnel aerosol consisted of coarse particles with high iron content, while the properties of the coarse particles in the road tunnel were strongly influenced by whether the road surface was wet or dry. In wet conditions, concentrations were relatively low and iron and sulfur dominating elements, while silicon, potassium, calcium and iron from suspension and road wear dominated during dry conditions. The content of elemental carbon, most likely from the pantograph, were unexpectedly high in the railroad tunnel. An older type of train with a large proportion of mechanical brakes were suggested to be responsible to the main particle emissions in the railway tunnel. The report concludes with a discussion and proposals for action against particle sources in the various underground environments.

  • 9.
    Gustafsson, Mats
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Blomqvist, Göran
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Elmgren, Max
    SLB-analys.
    Janhäll, Sara
    RISE.
    Johansson, Christer
    Stockholms universitet. Institutionen för miljövetenskap och analytisk kemi.
    Järlskog, Ida
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Lundberg, Joacim
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Norman, Michael
    SLB-analys.
    Silvergren, Sanna
    SLB-analys.
    Driftåtgärder mot PM10 i Stockholm: utvärdering av vintersäsongen 2016/20172018Report (Other academic)
    Abstract [en]

    Since 2011, Stockholm City has been working to reduce the impact of road dust through improved and specific street operations to reduce particulate levels in the air. Since its inception, effects on dust load and air quality have been investigated by VTI and SLB-analys at the Environmental Management in Stockholm. Specific measures have mainly included dust binding with calcium magnesium acetate (CMA) and vacuum cleaning with a Disa-Clean sweeper. The air quality measurements show that the environmental quality standard for PM10 is maintained for the fourth year in a row in Stockholm, which is partly due to operational measures. Additional daytime dust binding could be shown to lower the daily average PM10 concentration by 6%, while blockwise CMA treatment could not be shown to have any clear effect. Road dust load, measured as DL180 (road dust less than 180 μm), tend to have increased slightly compared to the previous season, especially in between the wheel tracks. The repaving of Folkungagatan has resulted in heavily increased dust load levels, but also lower PM10 levels than previous seasons. Evaluation of the possibilities for optimizing dust binding shows that several days with exceedances in autumn are missed, while several days in January are treated with CMA without an actual need to reach the limit value. Higher precision with forecast-based measures is needed to further optimize the efforts.

  • 10.
    Gustafsson, Mats
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Blomqvist, Göran
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Janhäll, Sara
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Mätning av luftkvalitet vid TestSite E182015Report (Other academic)
    Abstract [en]

    Measurements of air quality (PM10 and NOx (NO and NO2)) were made during the period 2013-03-16 to 2014-03-26 at TestSite E18, situated along the E18 highway between Västerås and Enköping. At TestSite E18 continuous measurements of traffic (eastbound direction) and meteorology are made. On the site, optical equipment for measuring road wetness was used during the campaign. The main purpose of the surveys is to create a data base for a highway traffic environment, which can be used for modeling air quality and calculation of exposure and health effects at a later stage. The results show that the concentrations do not exceed the relevant EQS. PM10 and NO2 are highest during the spring and autumn and lower in the summer period. The correlations between PM10 and nitrogen oxides are high in spring, low in summer and moderate in autumn and winter, suggesting that the summertime sources for PM10 at TestSite E18 are essentially others than traffic. Road surface moisture reduces PM10 levels strongly during spring when road dust is a major particle source. On a daily basis nitrogen dioxide and PM10 concentrations follow traffic variation, but with a clear secondary minimum at midday for nitrogen oxides. TestSite E18 generates large amounts of traffic and meteorology data, which can be used to analyze the correlation between these factors and air pollution at the site, and provide appropriate data for input to as well as validation of emission models.

  • 11.
    Gustafsson, Mats
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Blomqvist, Göran
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Janhäll, Sara
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Johansson, Christer
    Stockholms universitet. Institutionen för miljövetenskap och analytisk kemi.
    Järlskog, Ida
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Lundberg, Joacim
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Norman, Michael
    SLB-analys.
    Silvergren, Sanna
    SLB-analys.
    Driftåtgärder mot PM10 i Stockholm: utvärdering av vintersäsongen 2015–20162017Report (Other academic)
    Abstract [en]

    Since 2011, Stockholm has made special efforts to reduce PM10 levels in the city. The efforts mainly include dust binding with CMA (calcium magnesium acetate) and vacuum suction with a powerful dry vacuum suction machine. This report summarizes effects on particulate matter and road dust storage, as the actions taken by Stockholm City during the 2015–2016 season and discusses how measures can be further improved. The limit value for the environmental quality standard was not exceeded for the 2015–2016 season for the third consecutive year, but the number of days with PM10 levels over the environmental quality standard was higher than in the previous season, which had a record low number of exceedances. The evaluation of daytime dust binding was complicated by the fact that the CMA was also used on the reference street, which caused to much uncertainties to provide quantitative analysis of its effect this season. Block-wise dust binding and vacuuming could not be evaluated due to dust contamination from a construction site. The dust load on the streets varies from a few g/m2 to about 250 g/m2 depending on the street and season and is highest during the winter (Dec–Jan). A trend towards lower dust loads is broken this season on several streets, which may be due to the damper streets in spring. Analyses made on the connection between dust load, PM10 and impacting factors, as well as a condition-based calculation method suggests that dust binding in spring is important for keeping the levels down, while dust binding in autumn and winter is more often “unnecessary” (the levels would probably not have exceeded the limit value also without dust binding).

  • 12.
    Gustafsson, Mats
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Blomqvist, Göran
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Janhäll, Sara
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Johansson, Christer
    Institutionen för tillämpad miljövetenskap (ITM), Stockholms universitet.
    Norman, Michael
    SLB-analys, Miljöförvaltningen, Stockholms stad.
    Driftåtgärder mot PM10 i Stockholm: utvärdering av vintersäsongen 2012–20132014Report (Other academic)
    Abstract [en]

    Sweden is exceeding the limit values in the EU air quality directives and an important cause is the high concentrations of inhalable particles (PM10) that occurs during winter and spring. Wear of road pavements and winter operation like sanding are important sources for these high concentrations. The city of Stockholm has the largest air quality problems due to many badly ventilated street canyons with high traffic flows. Since 2011 an intensified mitigation work is intended to reduce PM10 concentrations. In this work, some streets are used as test streets for different measures and the resulting PM10 concentrations are compared to concentrations on un-treated reference streets. The results of the season 2011–2012 showed that dust binding with CMA (calcium magnesium acetate) was the most effective measure, while cleaning with an advanced sweeper with vacuum, could not be proven to give any reducing effects on PM10. The trials have been extended with two more test sites during the season 2012–2013, presented in this report. The reason for this was to be able to evaluate a new kind of vacuum sweeper, which does not use water and therefore can be used also during sub-zero conditions. The results show that dust binding with CMA is still the most effective method to reduce high PM10 concentrations resulting from road dust suspension and that the effect can be seen also the day after treatment. Cleaning the streets with the new vacuum cleaner could not be shown to give a significant reduction of PM10 concentrations, even though samples showed that the machine actually picked up fine particles. As during the previous season, the amount of road dust has been sampled and analyzed. The road dust depot increases during winter and reaches a maximum in early spring but is very low in the beginning and at the end of the winter season. This shows the importance of pavement wear and winter operation measures for the road dust depot. The dust binding effect is reflected in higher dust amounts with finer particle size distributions on the treated streets. As CMA might give reduce friction, friction measurements were performed, but no friction problems could be detected. Road surface texture was detected and this indicate that texture is an important parameter for the size of the road dust depot and therefore also for the dust suspension potential.

  • 13.
    Gustafsson, Mats
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Blomqvist, Göran
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Janhäll, Sara
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Johansson, Christer
    SLB-analys.
    Norman, Michael
    SLB-analys.
    Driftåtgärder mot PM10 i Stockholm: utvärdering av vintersäsongen 2013–20142015Report (Other academic)
    Abstract [en]

    Since 2011, intensified efforts are made to reduce levels of PM10 in Stockholm, where the problems are extensive. This report includes the results and evaluation of the measures taken during the winter season 2013–2014. The lowest PM10 levels since records began in Stockholm, were measured during the season and the limit values for the environmental quality standard is managed by a wide margin, which at least partially can be attributed to the intensified measures. The winter was unusually mild and snow-free and this has probably contributed to that, the typically large quantities of road dust that accumulates on the road surface in winter were able to leave the system through suspension, cleaning and drainage without high particulate levels resulting. During dry periods, frequent dust binding has helped to suppress high PM10 levels. The usually sharp PM10 peak in spring did not appear to the same extent as previous years. The block-wise CMA (calcium magnesium acetate) treatment was shown to provide additional reducing effect on PM10 levels, while the CMA + KF (potassium formate) treatment did not appear to have any impact. The measurements of the road dust load show the same seasonal fluctuations as in previous years, with large amounts during winter and early spring and lower in fall and late spring. All streets, except Hornsgatan, show a gradual decrease of road dust load over the three seasons with available data. The proportion of particles smaller than 10 microns in the dust increases from autumn to winter and decreases again in the spring. The organic proportion varies between 10 and 20 per cent by weight of DL180 (dust load less than 180 μm)and also exhibit a seasonal variation, where the proportion is higher in autumn and lowest in early spring. In a specific evaluation of the cleaning machine, a reduction of the road dust load could be observed.

  • 14.
    Gustafsson, Mats
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Blomqvist, Göran
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Janhäll, Sara
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Norman, Michael
    SLB-analys.
    Johansson, Christer
    Stockholms universitet. Institutionen för miljövetenskap och analytisk kemi.
    Driftåtgärder mot PM10 i Stockholm: utvärdering av vintersäsongen 2014–20152016Report (Other academic)
    Abstract [en]

    Since 2011, intensified efforts are made to reduce the levels of PM10 in Stockholm. This report presents results and evaluation of the efforts made during the winter season 2014–2015. The season has the lowest PM10 concentrations and the lowest number of exceedances of the environmental quality standard for PM10 since measurements started in Stockholm in 2000. Calculations using the NORTRIP model shows that both increased dust binding, reduced use of studded tires, lower background concentration and differences in meteorology are all factors that contributed to reduced levels from 2013 to 2015. Treatment with CMA + KF (potassium formate) did not appear to give any impact on PM10 levels, while block-wise dust binding gave an additional, but not significant, positive effect.

    The dust load on the road surface has a declining trend in all streets except Hornsgatan over the past three years and has, as in previous seasons, a seasonal variation with large amounts in winter and early spring and low in October and May. Detailed measurements showed a strong variation in the dust load across streets, with large accumulations outside the driving lane. Road surface texture is considered to play an important role in the accumulation of dust as it affects both the suspension from traffic, as well as the ability to clean off the dust. The report provides, based on the season’s results, combined with data on measures and meteorology, some suggestions for how measures can be improved and also provides examples of how additional needs or unnecessary efforts can be retrieved from the existing data.

  • 15.
    Gustafsson, Mats
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Blomqvist, Göran
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Järlskog, Ida
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Lundberg, Joacim
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Janhäll, Sara
    RISE.
    Elmgren, Max
    SLB-analys.
    Johansson, Christer
    SLB-analys.
    Norman, Michael
    SLB-analys.
    Silvergren, Sanna
    SLB-analys.
    Road dust load dynamics and influencing factors for six winter seasons in Stockholm, Sweden2019In: Atmospheric Environment: X, ISSN 2590-1621, Vol. 2, article id 100014Article in journal (Refereed)
    Abstract [en]

    Traffic related non-exhaust particulate sources and road dust are an increasingly important source for PM10 air pollution as exhaust sources are decreasing due to regulations. In the Nordic countries, the road dust problem is enhanced by use of studded tyres, causing increased road wear and winter road maintenance including gritting. Efforts to reduce road dust emissions requires knowledge on temporal and spatial road dust load dynamics. The city of Stockholm, Sweden, has therefore financed seasonal (October to May) road dust sampling to be able to optimize their winter and spring time street operation measures for reduced road dust emissions. This work describes the outcome of six seasons (2011/2012–2016/2017) of road dust sampling in five central streets using the VTI wet dust sampler (WDS).The results show that road dust load, expressed as DL180 (dust load smaller than 180 μm) has a seasonal variation with the highest loads (up to 200 g/m2) in late winter and early spring and a minimum (down to about 15 g/m2) in early autumn and late spring. The dust load varies between streets and is depending on pavement surface properties. On a smaller scale the dust load has a high variability across streets due to differences in rates of suspension from different parts of the road surface, with low amounts in wheel tracks and higher in-between and outside the tracks. Between 2 and 30% of the DL180 is smaller than 10 μm and could directly contribute to PM10 emissions. In general, higher road surface texture leads to higher dust loads, but the condition of the pavement (e.g. cracks, aggregate loss) might also have an effect. A new, wear resistant pavement accumulated markedly higher road dust amounts than a several years old pavement. This paper closes with a discussion on the complex relation between road dust load and PM10 concentrations and a discussion on the challenges and comparability of road dust sampling techniques and measures.

  • 16.
    Gustafsson, Mats
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Blomqvist, Göran
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Järlskog, Ida
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Lundberg, Joacim
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Niska, Anna
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Janhäll, Sara
    RISE.
    Norman, Michael
    SLB-analys.
    Eneroth, Kristina
    SLB-analys.
    Johansson, Christer
    Stockholms universitet. Institutionen för miljövetenskap och analytisk kemi.
    Optidrift: optimerad vinter- och barmarksdrift för bättre luftkvalitet2019Report (Other academic)
    Abstract [en]

    Operation of streets and roads, in addition to accessibility and safety, also affects environmental aspects such as air quality. Measures such as sanding and salting affect the content of inhalable particles (PM10) in the air. On the other hand, operational measures that are made to reduce the suspension of particles in the spring can have an effect on the winter operation, because the salt solutions used also act as de- and anti-icing agents. The project has investigated the possibilities of optimizing street operations from these aspects, with a focus on air quality. In various activities, views and experiences were gathered about problem images and solutions from industry, road managers and practitioners. A road dust sampler, WDS II, was developed. Evaluations of the effect of different coil and cleaning variants on the road dust load showed that a positive effect of the methods requires that there is relatively much dust on the road surface. Optimization tests showed that good forecasting of dust binding is important for a good result. A criteria-based analysis showed that no optimization of the dust binding occurred during the project period. Overall, the project's original goal of being able to propose an optimized street operation in a district in Stockholm has not been achieved, mainly due to current operating contracts and of the high priority of the environmental quality objective (PM10) and accessibility in the city. On the other hand, Optidrift has identified success factors and problems with the street operation, resulting in increased knowledge about the street operations' effects on dust load and air quality, and developed useful evaluation methods and scenario analyzes useful in continued work on improving and optimizing winter and barge operations.

  • 17.
    Janhäll, Sara
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Review on urban vegetation and particle air pollution: Deposition and dispersion2015In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 105, p. 130-137Article in journal (Refereed)
    Abstract [en]

    Urban vegetation affects air quality through influencing pollutant deposition and dispersion. Both processes are described by many existing models and experiments, on-site and in wind tunnels, focussing e.g. on urban street canyons and crossings or vegetation barriers adjacent to traffic sources. There is an urgent need for well-structured experimental data, including detailed empirical descriptions of parameters that are not the explicit focus of the study.

    This review revealed that design and choice of urban vegetation is crucial when using vegetation as an ecosystem service for air quality improvements. The reduced mixing in trafficked street canyons on adding large trees increases local air pollution levels, while low vegetation close to sources can improve air quality by increasing deposition. Filtration vegetation barriers have to be dense enough to offer large deposition surface area and porous enough to allow penetration, instead of deflection of the air stream above the barrier. The choice between tall or short and dense or sparse vegetation determines the effect on air pollution from different sources and different particle sizes.

  • 18.
    Janhäll, Sara
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Vegetationens inverkan på luftmiljön2015Report (Other academic)
    Abstract [en]

    Vegetation impacts the local air quality both positively and negatively. The positive effect is that air pollution concentration can be reduced by deposition on the vegetation surface and the air filtered. The total amount of air pollution is thus reduced. The negative effect is the ability of vegetation to act as windbreaks reducing the wind speed, which reduces the dilution of local emissions and can increase the levels in the surrounding area. In dense urban environments where dilution already without vegetation may be limited, such as in narrow street canyon with traffic emissions, this is a big risk. Vegetation can also be placed as a barrier between the emission sources (often major traffic routes) and the population, so that the transport of pollution from the source to the population may be limited, and the air is filtered on its way. This report describes the research in the area at present, and is mainly based on the scientific literature. It is at present difficult to describe vegetation in a way that simply relates to its effect on air quality. An example is the vegetation density can be measured in several ways, and best describes the effect either on wind movement or on deposit. The particle size of the pollution is of major importance to the processes, while chemical effects have been omitted in the description. Vegetation-curtains and different types of street canyon are studied with references to all the studies that is reported. The recommendations, explained in detail in the report, are: • place the vegetation near the source of air pollution, where the concentrations are high, increasing the ability to filter out pollution or redirect the polluted air, • ensure that the vegetation does not reduce the dilution of pollutants, for example avoiding close planting of dense trees in narrow and busy street canyons, where pollution is not easily diluted, • use vegetation barriers between transport and population, to introduce a deposit surface and control of the air movements, but preferably low hedges if dilution is limited at the site, • wall and roof vegetation in dense urban environments increases the deposition surface and has a limited restriction of ventilation compared to free-standing vegetation, • plan the vegetation from the start in view of all the effects of vegetation that can occur in a complex urban environment, and level different environmental effects against each other.The result has also been published scientifically in Janhäll (2015) “Review on urban vegetation and particle air pollution – deposition and dispersion” in the journal Atmospheric environment, 105, 130–137.

  • 19.
    Janhäll, Sara
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Carlson, Annelie
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Möjligheter till minskade koldioxidutsläpp genom trafikledning: en förstudie2017Report (Other academic)
    Abstract [en]

    Traffic management can affect the emissions of greenhouse gases, mainly through traffic exhaust emissions, but, to some extent, also since efficient traffic management can delay or avoid new investment in transportation infrastructure by streamlining the use of the existing structure.

    This project compiles existing literature evaluating the effects of traffic managements on climate gas emissions, i.e. how the management can alter traffic flows and how road users adapt to the information and how these changed traffic flows are reflected on emissions of climate gases. Some difficulties have been revealed, and further studies are recommended.

    Quantifying and evaluating the effects of climate gas emissions is heavily dependent on the emission models and assumptions used. Some development in this area is proposed, especially in driving behavior related to congestion situations. There is also a large habituation regarding road user effort to find and use traffic information which leads to increased opportunities for activities that affect emissions. Also, changes in behavior and technological advances should be taken into account if older investigations are used for decision making.

    The authors see great opportunities for VO traffic management and traffic information to reduce climate gas emissions from traffic by a conscious climate mitigation.

  • 20.
    Janhäll, Sara
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Carlson, Annelie
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Larsson, Pontus
    Uppdatering EVA-kalkylen: nya emissionsfaktorer beräknade med PHEM2017Report (Other academic)
    Abstract [en]

    The current European emission model, HBEFA, specifies emission factors for different driving patterns and vehicle types. This model does not study the example of individual intersections. This study utilizes the same microscopic model, PHEM (www.tugraz.at), as HBEFA to calculate also intersection emissions and emissions of links without intersections. With PHEM the release of four vehicle types (cars fueled by diesel or petrol and trucks with and without trailers) calculated for several different road classes according to the division still used in the models EVA and CAPCAL. To illustrate the emissions of intersections calculations for emissions for a quick stop to rest and then the withdrawal of the original speed is also presented.

    In addition to a description of the method of how the new emissions have been calculated in the new tables also include suggestions of future updating of the model. In addition, reported the conclusion of tests and comparisons to facilitate the transition from the current basic model VETO to PHEM. The calculations show that previous assumptions about the significantly lower emissions of vehicles have not been met, and that the vehicle speed impact on emissions has changed., We suggest that more vehicle types will be included in the model at the next update.

    The model simulates the CO2, SO2, fuel consumption, HC / VOC, CO, NOx, NO2 and exhaust particles, but the report only presents fuel consumption. However, all other parameters can be obtained directly from the authors. The report first provides a brief description of the different emission models, how the calculations are done up to now and then how adaptations and updates led to the resulting emission factors.

  • 21.
    Janhäll, Sara
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Genell, Anders
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Jägerbrand, Annika
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Trafikinformation och miljöeffekter: beräkningar av omledningseffekter2013Report (Other academic)
    Abstract [en]

    This project aims at calculating the environmental impact of traffic with a new computational model. A list of possible measures to reduce environmental effects using traffic information is given, aiming at improving energy efficiency, air quality, noise, and environmental impact. The use of traffic information to control traffic is growing, especially in urban environments where congestion impacts trafficability, while alternative routes are available. In the road sector The Swedish Transport Administration usually informs the traveller directly, while in the rail sector information is directed to the train companies who then inform travellers/drivers. This affects the ability to manage traffic, and creates problems for the intermodal information. This report focuses on the urgent environmental impact of traffic, although a review of long-term effects are included. Only the change in traffic and driving style affects the calculations. Many environmental impacts are affected by traffic, such as air pollution, noise, greenhouse gas emissions, but also the barrier effects, light pollution, water pollution and soil disturbance in sensitive areas. Calculations with the model show how emissions are affected by driving mode, and how the population exposure is affected. The existing models are highly simplified and development in emission modeling, exposure, effects of exposure, and model implementation is essential.

  • 22.
    Janhäll, Sara
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Gustafsson, Mats
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Andersson, Karl
    Järlskog, Ida
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Lindström, Thomas
    Utvärdering av städmaskiners förmåga att reducera vägdammsförrådet i gatu- och tunnelmiljöer i Trondheim2016Report (Other academic)
    Abstract [en]

    To avoid exceeding the environmental air quality standards for particulate matter (PM10) Norwegian Public Roads Administration Directorate of Public Roads (Statens vegvesen Vegdirektoratet) in Trondheim, Norway, has implemented an attempt to clean a road tunnel and a stretch of road with three different cleaning machines to reduce the amount of dust of the road. A large number of other tests is presented in the main report, while the present report focuses on how large the road dust depot has been before and after cleaning with different machines in the different environments.

    The results show that two of the three different machines will reduce the road dust depot efficiently in the street environment, while the road dust depot increases of cleaning in the tunnel environment. One theory might be that this may be due to the fact that even the walls and ceiling are cleaned in the tunnel environment, which could lead to the cleaning moves particles from the ceiling and walls to the road surface. Tunnel cleaning is carried out with the cleaning solution, which gives a different chemical environment, which can dissolve way the dust further down in the texture and make it for the sampler.

  • 23.
    Janhäll, Sara
    et al.
    Göteborgs Universitet.
    Hallquist, M.
    Göteborgs Universitet.
    Pettersson, J. B. C.
    Göteborgs Universitet.
    Samuelsson, M.
    Göteborgs Universitet.
    Svane, M.
    Göteborgs Universitet.
    Surface ionization detection of particles as an indicator for marine air2004In: Journal of Aerosol Science, ISSN 0021-8502, E-ISSN 1879-1964, Vol. 35, no SUPPL. 2, p. 1003-1004Article in journal (Refereed)
  • 24.
    Janhäll, Sara
    et al.
    Göteborgs Universitet.
    Hallquist, Mattias
    Göteborgs Universitet.
    A novel method for determination of size-resolved, submicrometer particle traffic emission factors2005In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 39, no 19, p. 7609-7615Article in journal (Refereed)
    Abstract [en]

    A novel approach to determine size-segregated particle number emission factors for traffic is presented. It was proven that using limited data sets (800-2000 samples) statistically significant emission factors from road traffic can be extracted. In this study, data from four sites were used for calculating emission factors (rural and urban roadside, urban rooftop, and urban background). The measurements were performed using SMPS/DMPS (scanning or differential particle sizers) from TSI and commercial gas analyzers. Describing the particle concentration as a ratio to an exhaust trace gas, e.g. NOx, the dilution effect will be minimized.

    This ratio is easily compared among different studies. By knowledge of the emission factor of the chosen trace gas the emission ratio can be converted to an emission factor for particle numbers of defined particle sizes. For the presented method only one measurement site is needed, where the difference between high and low (background) traffic exposure is used. To define high and low traffic exposure, the best result was obtained using high ratio of [NO] to [NO2] and low [NOx], respectively. Emission ratios for 10-100-nm particles at two road sites, one high-speed 90-kmph rural case and one urban, slower, and more congested situation, were determined to (35±15) × 1014 and (24±8) × 1014 particles per mole NOx, respectively.

  • 25.
    Janhäll, Sara
    et al.
    Göteborgs Universitet.
    Jonsson, Åsa M
    Göteborgs Universitet.
    Molnár, Peter
    Göteborgs Universitet.
    Svensson, Erik A
    Göteborgs Universitet.
    Hallquist, Mattias
    Göteborgs Universitet.
    Size resolved traffic emission factors of submicrometer particles2004In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 38, no 26, p. 4331-4340Article in journal (Refereed)
    Abstract [en]

    Size resolved emission factors for submicrometer particles related to trace gases have been obtained from measurement data at a suburban road side, with a traffic intensity of 18,000 vehicles per day. Number of particles with diameter 10-368 nm, trace gases (NO, NOx,O3 and SO2), traffic and meteorology parameters were measured outside of Göteborg, Sweden.

    Size distributions of small particles at the site are presented and their relation to meteorological and traffic related variables was evaluated. Wind speed correlated negatively with 10-368 nm particles and temperature correlated negatively with the smaller particles (10-60 nm). Nitric oxide was shown to be a better tracer for traffic related ultrafine particles, than traffic intensity itself.

    The calculated emission factor, with errors at 95% confidence level, for particles in the range 10-368 nm is presented in relation to nitrogen oxides. The emission factors were 268±60 and 176±37 particles cm-3 per ppb NO and NOx, respectively. The particle emission factors for 10-100, 10-50, 50-170 and 170-368 nm were 260±70, 228±52, 41±11 and <1 particle cm-3 per ppb NO, respectively. The size distribution of the emissions is given by number of particles normalised by the width of the size bin, i.e. in units of dNdlogDp-1 ppb-1. The maximum normalised emission factor was 450 cm-3 per ppb NO for 20 nm particles. The shape of the size distribution of emissions revealed one sharp peak at 20 nm, with a small shoulder at 70 nm.

  • 26.
    Janhäll, Sara
    et al.
    Chalmers Tekniska Högskola.
    Molnár, Peter
    Chalmers Tekniska Högskola.
    Hallquist, Mattias
    Chalmers Tekniska Högskola.
    Vertical distribution of air pollutants at the Gustavii Cathedral in Göteborg, Sweden2003In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 37, no 2, p. 209-217Article in journal (Refereed)
    Abstract [en]

    Atmospheric trace gases and particles were measured at two heights at the Gustavii Cathedral in Göteborg, Sweden, during 7 weeks in September and October 1999. The Gustavii Cathedral is situated in the city centre of Göteborg, which is near the harbour area and encircled by heavy traffic some hundred metres away. The main body of the church is as high as the surrounding buildings, while the tower extends well above. The sampling points were placed on the west wall of the tower at 10 and 32 meter height, i.e. well below and above the roof top level of surrounding buildings, respectively.

    Sulphur dioxide and nitric acid were sampled using the denuder technique and analysed by Ion Chromatography, IC. Total suspended particulates (TSP) were sampled using filter cups and subsequently analysed by energy dispersive X-ray fluorescence spectroscopy (EDXRF). In addition to the diurnal sampling of species, nitrogen oxides were measured using chemiluminescence detectors. Additional data from the Environmental Office in Göteborg was used in the analysis.

    Differences between the concentrations measured at the upper and lower levels were calculated and their variation and dependence on meteorological factors were evaluated. On the average larger concentrations were found at the lower level for soil derived elements and TSP, while nitric acid and nitric oxide showed larger concentrations at the upper level. Sulphur dioxide and nitrogen dioxide, as well as many of the elements in the TSP, showed equal concentrations at the two levels. However, depending on wind direction the measured differences of nitrogen oxides could be both positive and negative.

  • 27.
    Järlskog, Ida
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Blomqvist, Göran
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Gustafsson, Mats
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Janhäll, Sara
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Utvärdering av städmaskiners förmåga  att reducera vägdammsförrådet  i gatu- och tunnelmiljöer: En fältstudie i Trondheim 20162017Report (Other academic)
    Abstract [en]

    In May 2016, VTI conducted a field study in Strindheim tunnel and on Haakon VII street on behalf of the Norwegian Road Administration in Trondheim aiming at comparing and evaluating the ability of cleaning techniques to reduce the road dust depot in street and tunnel environments. 

    The result showed that after a first cleaning effort in the tunnel with the BEAM rotorclean (roadway only), a larger dust load was detected than before cleaning. This is believed to be due to the flushing of dust from the edge of the road or the removal of dust cemented in the road surface texture. After a second cleaning effort, where the walls and ceilings are cleaned and the road is cleaned again, a reduction in dust load could be distinguished, but only in the roadway, not near the edge.

    On Haakon VII street, two different cleaning machines, Disa Clean and Val’Air rotor cleaner were used, the former being a dry vacuum sweeper and the latter using rotary high pressure washing combined with vacuum. Sampling was conducted in six fields. The result showed that greatest effect was achieved with Disa Clean in combination with high pressure rinsing as well as with Val’Air rotor cleaner at a driving speed of 3 kilometer per hour. In both cases there were significant differences in dust storage before and after cleaning.

  • 28.
    Lundberg, Joacim
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment. KTH.
    Blomqvist, Göran
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Gustafsson, Mats
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Janhäll, Sara
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Texture influence on road dust load2017In: Proceedings of the 22nd International Transportation and Air Pollution Conferens, 2017, p. 14-Conference paper (Refereed)
    Abstract [en]

    The objective of this study was to investigate the connection between pavement texture and the maximum dust load retention at a low speed. One of the main sources of PM (Particulate Matter) in the urban environment is the traffic. Traffic contributes not only to exhaust emissions, but also to direct emission from abrasion wear of pavements, tyres and brakes as well as emission from suspension of available road dust on the road surface. This dust is partially stored in the road surface macro texture. Dust accumulate on the surface due to several different mechanisms and transport phenomena’s. Examples of transport mechanisms affecting the road dust load and thus the storage in the texture include precipitation, evaporation, turbulence from traffic, wetting of the road surface binding particles to it, sanding and crushing of the sand etc.

  • 29.
    Lundberg, Joacim
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Blomqvist, Göran
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Gustafsson, Mats
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Janhäll, Sara
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Järlskog, Ida
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Wet Dust Sampler: a Sampling Method for Road Dust Quantification and Analyses2019In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 230, no 8, article id 180Article in journal (Refereed)
    Abstract [en]

    In northern countries, the climate, and consequently the use of studded tyres and winter traction sanding, causes accumulation of road dust over winter and spring, resulting in high PM10 concentrations during springtime dusting events. To quantify the dust at the road surface, a method—the wet dust sampler (WDS)—was developed allowing repeatable sampling also under wet and snowy conditions. The principle of operation is flushing high-pressurised water over a defined surface area and transferring the dust laden water into a container for further analyses. The WDS has been used for some time and is presented in detail to the international scientific community as reported by Jonsson et al. (2008) and Gustafsson et al. (2019), and in this paper, the latest version is presented together with an evaluation of its performance. To evaluate the WDS, the ejected water amount was measured, as well as water losses in different parts of the sampling system, together with indicative dust measurement using turbidity as a proxy for dust concentration. The results show that the WDS, when accounting for all losses, have a predictable and repeatable water performance, with no impact on performance based on the variety of asphalt surface types included in this study, given undamaged surfaces. The largest loss was found to be water retained on the surface, and the dust measurements imply that this might not have as large impact on the sampled dust as could be expected. A theoretical particle mass balance shows small particle losses, while field measurements show higher losses. Several tests are suggested to validate and improve on the mass balances. Finally, the WDS is found to perform well and is able to contribute to further knowledge regarding road dust implications for air pollution.

  • 30.
    Lundberg, Joacim
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment. KTH.
    Janhäll, Sara
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Gustafsson, Mats
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. KTH.
    Calibration of the Swedish Studdded Tyre Abrasion Wear Prediction Model and the Implication for the NORTRIP Road Dust Emission Model2018In: Transportation Research Board 97th annual meeting, Washington, D.C., 2018Conference paper (Refereed)
    Abstract [en]

    An experimentally based prediction model of rut development due to studded tyres is available in Sweden and which had been found to work well. However, since it has not been validated since 2007, during which traffic as well as road and tyre design have developed, the question has arisen regarding the model’s current validity. Also, since the prediction model is used in the NORTRIP (NOn-exhaust Road Traffic Induced Particle emission) emission model, a natural question is how a change in the wear model will affect the emission model. In this paper, two versions of the abrasion model are compared to measurements at several recently constructed roads in Sweden to investigate the validity, while also proposing changes to allow for continued use. In addition, the impact on NORTRIP is briefly investigated. The paper first describes the abrasion models and their calibration, as well as the test sections for calibration. Both versions of the model, as expected, overestimated the wear and an update was suggested. It was also found that NORTRIP is indicatively affected by overestimating the contribution of pavement wear to the emissions.

  • 31.
    Lundberg, Joacim
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Janhäll, Sara
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Gustafsson, Mats
    Swedish National Road and Transport Research Institute, Society, environment and transport, Enviroment and traffic analysis.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Calibration of the Swedish studded tyre abrasion wear prediction model with implication for the NORTRIP road dust emission model2019In: The international journal of pavement engineering, ISSN 1029-8436, E-ISSN 1477-268XArticle in journal (Refereed)
    Abstract [en]

    An experimentally based prediction model of road abrasion wear due to studded tyres is available in Sweden and has been found to work well. However, it has not been validated since 2007, and since then road surfaces and tyre design have developed, and the question has arisen regarding the model’s current validity. The abrasion wear model is used in the NORTRIP emission model (NOn-exhaust Road Traffic Induced Particle emission modelling), and the effect of a recalibrated abrasion wear model on the emission model is shown. In this paper, the abrasion wear model is compared to full-scale field measurements at several recently constructed roads in Sweden to investigate its validity, while also proposing changes to allow for continued use. It is concluded that the model overestimates the wear and an update is suggested. In addition, the impact on NORTRIP emission predictions is briefly investigated. There were also indications that NORTRIP is affected by the abrasion model overestimating the contribution of pavement wear to the particle emissions.

  • 32.
    Molnár, Peter
    et al.
    Chalmers Tekniska Högskola.
    Janhäll, Sara
    Chalmers Tekniska Högskola.
    Hallquist, Mattias
    Chalmers Tekniska Högskola.
    Roadside measurements of fine and ultrafine particles at a major road north of Gothenburg2002In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 36, no 25, p. 4115-4123Article in journal (Refereed)
    Abstract [en]

    Particle measurements were conducted at a road site 15km north of the city of Gothenburg for 3 weeks in June 2000. The size distribution between 10 and 368nm was measured continuously by using a differential mobility particle sizer (DMPS) system. PM2.5 was sampled on a daily basis with subsequent elemental analysis using EDXRF-spectroscopy. The road is a straight four-lane road with a speed limit of 90kph. The road passing the site is flat with no elevations where the vehicles run on a steady workload and with constant speed. The traffic intensity is about 20,000 cars per workday and 13,000 vehicles per day during weekends. The diesel fuel used in Sweden is low in sulphur content (<10ppm) and therefore the diesel vehicles passing the site contribute less to particle emissions in comparison with other studies. A correlation between PM2.5 and accumulation mode particles (100-368nm) was observed. However, no significant correlation was found between number concentrations of ultrafine particles (10-100nm) and PM2.5 or the accumulation mode number concentration. The particle distribution between 10 and 368nm showed great dependency on wind speed and wind direction, where the wind speed was the dominant factor for ultrafine (10-100nm) particle concentrations. The difference in traffic intensity between workday and weekend together with wind data made it possible to single out the traffic contribution to particle emissions and measure the size distribution. The results presented in combination with previous studies show that both PM2.5 and the mass of accumulation mode particles are bad estimates for ultrafine particles.

  • 33.
    Nerhagen, Lena
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics, TEK.
    Janhäll, Sara
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Exhaust emissions and environmental classifications of cars: what indicators are relevant according to external cost calculations?2015Report (Other academic)
    Abstract [en]

    This study is based on the questions raised by Folksam on how well the criteria currently used reflect the total environmental impact of exhaust emissions. One of the questions is whether diesel cars, being more fuel efficient, are preferable to gasoline cars given the differences in for example particle and NO2 emissions. In this paper we give an overview of the method used to calculate the external costs related to the exhaust emissions of cars, the Impact Pathway Approach (IPA). This type of assessment has previously been used to compare the environmental performance of gasoline versus diesel cars in a report by the former Swedish national road administration and in a recent paper on the taxation of cars in Belgium. We also provide an overview of recent research on the inputs used in these calculations. Based on information on emission tests of VW cars and information from the Swedish Transport Administration, we illustrate how different aspects influence the outcome of these calculations regarding exhaust emissions from cars. Regarding the specific question raised in this study about indicators for sustainable cars, we find that the indicators currently used, CO2 emissions, do not reflect the full environmental impact. Different types of vehicle technologies result in different combinations of emissions. With the large variety of car models, and with important differences between type approval and ”real driving” emissions, we conclude that apart from CO2 emissions, vehicle technology should be accounted for in the classification of cars. Concerning the difference between gasoline and diesel vehicles, important aspects to consider are: • differences in emissions of particulates where particle size or number and composition may be important to consider in addition to, or maybe even rather than, mass, • the difference in the ratio between NOx and NO2, as it affects local NO2 and ozone concentrations.

  • 34.
    Norman, Michael
    et al.
    Environment and Health Administration of the City of Stockholm.
    Sundvor, Ingrid
    The Norwegian Institute for Air Research (NILU).
    Denby, Bruce Rolstad
    The Norwegian Meteorological Institute (MET).
    Johansson, Christer
    Stockholms Universitet.
    Gustafsson, Mats
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Blomqvist, Göran
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Janhäll, Sara
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Modelling road dust emission abatement measures using the NORTRIP model: Vehicle speed and studded tyre reduction2016In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 134, p. 96-108Article in journal (Refereed)
    Abstract [en]

    Road dust emissions in Nordic countries still remain a significant contributor to PM10 concentrations mainly due to the use of studded tyres. Measures to reduce road dust emissions include speed reductions, reductions in studded tyre use, dust binding and road cleaning. In this paper the NORTRIP road dust emission model is used to simulate real world abatement measures that have been carried out in Oslo and Stockholm.

    In Oslo both vehicle speed and studded tyre share reductions occurred over a period from 2004 to 2006 on a major arterial road, RV4. In Stockholm a studded tyre ban on Hornsgatan in 2010 saw a significant reduction in studded tyre share together with a reduction in traffic volume. The model is found to correctly simulate the impact of these measures on the PM10 concentrations when compared to available kerbside measurement data.

    Meteorology can have a significant impact on the concentrations through both surface and dispersion conditions. The first year after the implementation of the speed reduction on RV4 was much drier than the previous year, resulting in higher mean concentrations than expected. The following year was much wetter with significant rain and snow fall leading to wet or frozen road surfaces for 83 % of the four month study period. This significantly reduced the net PM10 concentrations.

    In the years following the studded tyre ban on Hornsgatan road wear production through studded tyres decreased by 72 %, due to a combination of reduced traffic volume and reduced studded tyre share. However, after accounting for exhaust contributions and the impact of meteorological conditions in the model calculations, the net mean reduction in PM10 concentrations was ~50 %. The NORTRIP model is shown to be able to reproduce the impacts of both traffic measures and meteorology on traffic induced PM10 concentrations, making it a unique and valuable tool for predicting the impact of measures for air quality management applications.

  • 35.
    Odolinski, Kristofer
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics.
    Genell, Anders
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Janhäll, Sara
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Samhällsekonomiska effekter med en kombitransport: beräkningar på järnvägsvagnen Flexiwaggon2017Report (Other academic)
    Abstract [en]

    In Sweden and the EU, there is a stated need to combine more freight transports on road with railway. The aim is to reduce emissions of climate gases, as well as noise and other external effects such as congestion, accidents and wear and tear of the road. New innovations and transport solutions can be necessary to increase the number of combined road and railway freight transports. The transport solution analyzed in this study is a new railway wagon that can transport trucks at the speed of 160 km/h. The purpose of the study is to calculate the economic effects the new railway wagon can generate if it is used on a route where rail can be a viable alternative to road transport. In this, the environment and energy effects are studied, as well as the commercial cost.

    To define the contestable market between transport modes in a certain situation can be a challenging task, as there are many – and often interacting – factors that determine the mode choice. However, the literature states that route distance and the characteristics of the goods being transported are crucial factors for mode choice, where examples of the characteristics of goods are its value, damage sensitivity, time sensitivity, and weight (these can to a large extent be captured by the type of good). Freight transport on rail are often considered to be a viable approach on distances over 300 kilometres. In this study, we use three project cases with the route distances 280, 420 and 670 kilometres. We assume that distinct groups of goods are transported, as this will have an impact on the calculations.

    The base cases (with the abbreviation JA in the study) comprises road transport carried out by trucks with a trailer. A major part of the distance in the project cases (abbreviated UA) is covered by trains on which the trucks have been loaded. There are no truck drivers on the train transport.

    The environment and energy effects (exclusive noise) are calculated using a tool provided by the Network for Transport Measures (NTM). Differences in carbon dioxide, methane, nitrous oxide, sulfur dioxide, carbon monoxide, nitrogen oxides, and particulate matter are presented, where the project cases have lower emissions than the base cases. Moreover, a lower amount of energy is consumed in the project cases compared to the base cases.

  • 36.
    Shannigrahi, Ardhendu Sekhar
    et al.
    Göteborgs Universitet.
    Pettersson, Jan B. C.
    Göteborgs Universitet.
    Langer, Sarka
    Göteborgs Universitet.
    Arrhenius, Karine
    IVL.
    Hagström, Magnus
    Göteborgs Universitet.
    Janhäll, Sara
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment. Göteborgs Universitet.
    Hallquist, Mattias
    Göteborgs Universitet.
    Pathak, Ravi Kant
    Göteborgs Universitet.
    n-Alkanoic monocarboxylic acid concentrations in urban and rural aerosols: Seasonal dependence and major sources2014In: Atmospheric research, ISSN 0169-8095, E-ISSN 1873-2895, Vol. 143, p. 228-237Article in journal (Refereed)
    Abstract [en]

    We report new data on the abundance and distribution of n-monocarboxylic acids (n-MCAs) in fine- and coarse-mode aerosols in rural and urban areas of Sweden, and determine their possible sources. Overall, C6–C16n-MCAs accounted for ~ 0.5–1.2% of the total PM10 (particulate matter ≤ 10 μm) mass. In general, the C12–C16 fraction was the most abundant (> 75%), with the exception of wintertime samples from a rural site, where C6–C11 acids accounted for 65% of the total C6–C16n-MCA mass. Positive matrix factorization analysis revealed four major sources of n-MCAs: traffic emissions, wood combustion, microbial activity, and a fourth factor that was dominated by semi-volatile n-MCAs.

    Traffic emissions were important in the urban environment in both seasons and at the rural site during winters, and were a major source of C9–C11 acids. Wood combustion was a significant source at urban sites during the winter and also to some extent at the rural site in both seasons. This is consistent with the use of wood for domestic heating but may also be related to meat cooking. Thus, during the winter, traffic, wood combustion and microbial activity were all important sources in the urban environment, while traffic was the dominant source at the rural site. During the summer, there was considerable day-to-day variation in n-MCA concentrations but microbial activity was the dominant source. The semi-volatile low molecular weight C6–C8 acids accounted for a small (~ 5–10%) fraction of the total mass of n-MCAs. This factor is unlikely to be linked to a single source and its influence instead reflects the partitioning of these compounds between the gas and particle phases. This would explain their greater contribution during the winter.

  • 37.
    Vieira, Tiago
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Lundberg, Joacim
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Genell, Anders
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Sandberg, Ulf
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Blomqvist, Göran
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Gustafsson, Mats
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Janhäll, Sara
    RISE.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. University of Iceland.
    Porous pavement for reduced tyre/road noise and improved air quality: Initial results from a case study2019In: Proceedings of the 26th International Congress on Sound and Vibration, ICSV 2019, Canadian Acoustical Association , 2019Conference paper (Refereed)
    Abstract [en]

    One possible solution to reduce noise resulting from tyre-pavement interaction is to use a porous pavement surface. A porous surface will reduce noise by decreasing air pressure gradients in the tyre-pavement contact as well as by decreasing the acoustical impedance of the road surface and reducing the horn effect. While reducing noise, other functional aspects of a pavement such as abrasion wear which impacts on air pollution through generation and suspension of particles, friction and rolling resistance need to be addressed. This paper analyses the acoustical behaviour of a Double Layered Porous Asphalt (DLPA), applied in the city of Linköping, Sweden, as a solution to mitigate noise, compared to a non-porous Stone Mastic Asphalt (SMA) pavement used as reference. The analysis is based on Close Proximity noise measurements, both in absolute value and as frequency spectra, acoustical homogeneity over the surface length and sound absorption measurements. The acoustic analysis is combined with analyses of air quality measurements of PM10 (Particulate Matter with aerodynamic diameter < 10 µm) from two Tapered Element Oscillating Microbalance (TEOM) measurement stations placed near each different pavement section. The initial results indicate that the porous pavement results in a noise reduction of up to 5 dB for light vehicles, and up to 4 dB for heavy vehicles. So far, the DPLA shows approximately 52 % lower PM10 concentrations than the SMA. It should be noted that PM10 is influenced also by meteorological conditions, like humidity, background sources as well as vehicle properties, e.g. use of studded tyres, and that some of the observed decrease can be due to other aspects than porosity e.g. road surface moisture and wind direction. In conclusion, the use of a porous pavement shows promising results from both acoustical and air quality aspects, given the initial, short term results

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