Blomqvist, Göran

Bohgard, Mats

Dahl, Andreas

Gudmundsson, Anders

Gustafsson, Mats

Swietlicki, Erik

English

Lund University Publications

LUND UNIVERSITYPO Box 117221 00 Lund+46 46-222 00 00Size-Resolved Emission Factor for Particle generation Caused by Studded Tires -Experimental ResultsDahl, Andreas; Gudmundsson, Anders; Swietlicki, Erik; Bohgard, Mats; Blomqvist, Göran;Gustafsson, MatsPublished in:[Publication information missing]2006Link to publicationCitation for published version (APA):Dahl, A., Gudmundsson, A., Swietlicki, E., Bohgard, M., Blomqvist, G., & Gustafsson, M. (2006). Size-ResolvedEmission Factor for Particle generation Caused by Studded Tires - Experimental Results. [Publicationinformation missing], 2, 1681-1681.Total number of authors:6General rightsUnless other specific re-use rights are stated the following general rights apply:Copyright and moral rights for the publications made accessible in the public portal are retained by the authorsand/or other copyright owners and it is a condition of accessing publications that users recognise and abide by thelegal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private studyor research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portalRead more about Creative commons licenses: https://creativecommons.org/licenses/Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will removeaccess to the work immediately and investigate your claim.Size-Resolved Emission Factor for Particle Generation Caused by Studded Tires  – Experimental Results Andreas Dahl1, Anders Gudmundsson1, Erik Swietlicki2, Mats Bohgard1, Göran Blomqvist3 and Mats Gustafsson31Division of Ergonomics and Aerosol Technology, Lund University, P.O. Box 118, SE-221 00 Lund, Sweden2Division of Nuclear Physics, Lund University, P.O. Box 118, SE-221 00 Lund, Sweden3Swedish National Road and Transport Research Institute (VTI), SE-581 95 Linköping, SwedenINTRODUCTIONThe  European  24-hour  limit  value  for  particle matter with an aerodynamic diameter less than 10 µm (PM10) is often exceeded during winter and early spring in  the  major  Scandinavian  cities  due  to  the  use  of studded tires.MATERIAL AND METHODSThis  study  was  conducted  on  a  road  simulator, which  consists  of  four  electrically  driven  wheels running on a circular  track.  The simulator  was fitted with studded tires of a type which is commonly used on Light  Duty  Vehicles  (LDV)  in  the  Scandinavian countries during the winter season and the pavement is typical  for  city  streets.  The  particles  were  measured with an Aerodynamic Particle Sizer (APS, model 3021, TSI Inc., USA) equipped with a PM10-inlet.After the road simulator is started and accelerated to 70  km/h  the  particle  concentration  builds  up  and reaches  a  steady  state.  The  measured  change  in concentration of each APS-channel over  time can be described by assuming a box model.C t =C0 e−k tQk1−e−k tHere  C(t) is the concentration at time t,  C0 the initial concentration, k the first order loss rate constant and Q the particle source strength. RESULTSCurve fittings to the measured APS-channels of 1, 2.5 and 5 µm sized particles are shown in figure 1.Figure 1. Curve fittings for APS-channels over time.The  particle  generation  rate  was  extracted  from each channel fit and the size-resolved emission factors (E) are shown in figure 2. The sum of these emission factors gives a PM10 emission of 0.6 g/km. Figure 2. Size-resolved particle emission factors from LDV studded tires per km at 70 km/h.DISCUSSIONOur  estimated  PM10 emission  factor  agrees  with field measurements carried out in Stockholm, Sweden (Johansson, et al.,  2004) and Malmö, Sweden (Sjöberg and  Ferm,  2005).  Johansson  (2004)  found  the  PM10 emission factor to be 0.68 g/vehicle km in Stockholm in March when 70% of the vehicles were equipped with studded tires and Sjöberg and Ferm (2005) found an emission factor of 0.40 g/vehicle km in Malmö, when the studded tire density was 40%.Keywords: Traffic emission, PM10, Road wearREFERENCESJohansson, C., Norman, M., Omstedt, G., Swietlicki, E. (2004).  Particles  in  urban  areas  –  sources,  concentrations and the effects of different actions  on the concentration levels measured as PM10. SLB, Stockholm, Sweden, Report 4:2004Sjöberg, K., Ferm, M., (2005). Measurements of PM10 and  PM2.5 in  Malmö,  IVL,  Stockholm,  Sweden,  Report U 1756. This ongoing study is  financed by The Swedish Emission Resarch Programme (EMFO).0.010.11101000.1 1 10 100Dp [µm]dE/dlogDp[mg/km]02040600 1000 2000 3000Time [s]Mass concentration_        [µg/m³] 5 µm 5 µm Fit2.5 µm2.5 µm Fit 1 µm 1 µm FitUrban and Regional Aerosols1681New particle formation in the urban atmosphere of Helsinki during 1997-2004  Jyrki M. Martikainen, Tareq Hussein, Heikki Junninen, Miikka Dal Maso and Markku Kulmala Department of Physical Sciences, University of Helsinki, P.O. Box 64, FI-00014, Univ. of Helsinki, Finland   INTRODUCTION  Urban aerosol particles in Helsinki have been investigated for several years (Hussein et al. 2004). The investigations, so far, have been with respect to traffic emissions and meteorological conditions or other anthropogenic aerosol particle emissions. New particle formation (NPF) has not yet been investigated in Helsinki. On the other hand, NPF analysis have been well established at the boreal forest in Nordic countries as well as in the Finnish Lapland. It has been found that there is a specific yearly pattern in how often NPF are observed (Dal Maso et al. 2005 and Vehkamäki et al. 2004).  In this study we aim to investigate NPF events in Helsinki (60° 10’ N and 24° 57’ E, urban background) by utilizing the continuous aerosol particle number size distribution measurements since 1997.  METHODOLOGY  The aerosol particle measurements were performed with a Differential Mobility Particle Sizer (DMPS) (Aalto et al. 2001, Jokinen et al. 1997). The measurements were made at two different locations in Helsinki (Hussein et al. 2004): 1) nearby downtown at Siltavuori during May 5, 1997 – March 4, 2001, 2) SMEAR III measurement station at Kumpula (about 3 km north east Siltavuori) where the aerosol particle measurements have been since March 5th 2001.   The measured particle size range was 7–500 nm until March 9th 2003 when we upgraded the DMPS system to measure particle number size distributions with a wider size range between 3–1000 nm.  The visual analysis of NPF events was performed in daily bases. Day data sets were viewed randomly without any knowledge of the day or weather conditions. The whole data set was analysed four times. First two times there were partial figures including only the data range 7–500nm and in the two other investigations the full detection range was taken into consideration. That give us possibility to compare these two measuring system.  NPF events were classified in four different classes and one non-classified class. The days where there was more than a 3 hours gap or bad data were removed from the analysis. Class 1 contains days where there were clearly identified NPF events (figure 1). Class 2 includes days with high potential for NPF events; it means that there was identifiable growth or the NPF event tail, so it can not be classified as an event day. The days which were clearly not NPF event days, were classified in class 3. Class 4 included the days which were not identified to previous classes.     Figure 1. New particle formation event in August 2004, defined as class 1   RESULTS AND DISCUSSION   Urban air contains lot of anthropogenic aerosol particles (Anttila 2004, Laakso et al. 2003), as can be determined by the fact that the class 4 have a greater number of days classified to it. The probability of each class is shown in the figures 2 and 3, it is calculated as a 30 day sliding mean, where the number of event days was divided by the number of analyzed days.   Similar annual pattern for NPF events have been observed at the boreal forest in Southern Finland (Dal Maso et al. 2005) and in the rural part of Northern Finland (Vehkamäki et al. 2004). However, the probability observe NPF events in Helsinki is much lower than in these two other places because of the traffic emissions and high urban background particle number concentrations. Class 3 supports both class 1 and 2 on its behaviour as it was defined non-even class.   Urban and Regional Aerosols1682

Size-Resolved Emission Factor for Particle generation Caused by Studded Tires - Experimental Results

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Size-Resolved Emission Factor for Particle generation Caused by Studded Tires - Experimental Results

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