Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 6 9 2006 10.5194/acp-6-2411-2006 http://www.atmos-chem-phys.net/6/2411/2006/ http://www.atmos-chem-phys.net/6/2411/2006/acp-6-2411-2006.html http://www.atmos-chem-phys.net/6/2411/2006/acp-6-2411-2006.pdf 2411 2421 2006-06-29 Winter and summer time size distributions and densities of traffic-related aerosol particles at a busy highway in Helsinki A. Virtanen annele.virtanen@tut.fi T. Rönkkö J. Kannosto J. Ristimäki J. M. Mäkelä J. Keskinen T. Pakkanen R. Hillamo L. Pirjola K. Hämeri Tampere University of Technology, Institute of Physics, Aerosol Physics, P.O. Box 692, 33101 Tampere, Finland Finnish Meteorological Institute, Air Quality Research, Sahaajankatu 20 E, 00810 Helsinki, Finland Helsinki Polytechnics, Department of Technology, P.O. Box 4020, 00099 Helsinki, Finland Finnish Institute of Occupational Health, Department of Physics, Topeliuksenkatu 41, 00250 Helsinki, Finland University of Helsinki, Department of Physical Sciences, P.O. Box 64, 00014 University of Helsinki, Finland Number concentrations and size distributions of traffic related aerosol particles were measured at a roadside in Helsinki during two winter campaigns (10–26 February 2003, 28 January–12 February 2004) and two summer campaigns (12–27 August 2003, 6–20 August 2004). The measurements were performed simultaneously at distances of 9 m and 65 m from the highway. Total number concentrations were measured by a condensation particle counter (CPC) and particle size distributions by a scanning mobility particle sizer (SMPS) and an electrical low pressure impactor (ELPI). This study concentrates on data that were measured when the wind direction was from the road to the measurement site. The total concentrations in the wintertime were 2–3 times higher than in the summertime and the concentrations were dominated by nucleation mode particles. The particles smaller than 63 nm (aerodynamic diameter) constituted ~90% of all particles in the wintertime and ~80% of particles in the summer time. The particle total concentration increased with increasing traffic rate. The effect of traffic rate on particles smaller than 63 nm was stronger than on the larger particles. The particle distributions at the roadside consisted of two distinguishable modes. The geometric mean diameter (GMD) of nucleation mode (Mode 1) was 20.3 nm in summer and 18.9 nm in winter. The GMD of the larger mode consisting mostly of traffic related soot particles (Mode 2) was 72.0 nm in summer and 75.1 nm in winter. The GMD values of the modes did not depend on the traffic rate. The average particle density for each mode was determined by a parallel density fitting method based on the size distribution measurement made by ELPI and SMPS. The average density value for Mode 1 particles was 1.0±0.13 g/cm³ and 1.0±0.07 g/cm³ both in summer and winter respectively, while the average density value for Mode 2 was 1.5±0.1 g/cm³ and 1.8±0.3 g/cm³ for summer and winter, respectively. Abdul-Khalek, I. S., Kittelson, D. B., and Brear, F.: The influence of dilution conditions on diesel exhaust particle size distribution measurements, SAE technical paper series, no. 1999-01-1142, 1999. Charron, A. and Harrison, R. M.: Primary particle formation from vehicle emissions during exhaust dilution in the roadside atmosphere, Atmos. Environ., 37, 4109–4119, 2003. Gieshaskiel, B., Ntziachristos, L., Samaras, Z., Scheer, V., Casati, R., and Vogt, R.: Formation potential of vehicle exhaust nucleation mode particles on-road and in the laboratory, Atmos. Environ., 39, 3191–3198, 2005. Harris, S. J. and Maricq, M. M.: Signature size distribution for diesel and gasoline engine exhaust particulate matter, J. Aerosol Sci., 32, 749–764, 2001. Hussein, T., Puustinen, A., Aalto, P. P., Mäkelä, J. M., Hämeri, K., and Kulmala, M.: Urban aerosol number size distributions, Atmos. Chem. Phys., 4, 391–411, 2004. Imhof, D., Weingartner, E., Ordó\~nez, C.,Gehrig, R., Hill, M., Buchmann, B., and Baltensberger, U.: Real-world emission factors of fine and ultra fine aerosol particles for different traffic situations in Switzerland, Environ. Sci. Technol., 39, 8341–8350, 2005a. Imhof, D., Weingartner, E., Prévöt, A. S. H., Ordó\~nez, C., Kurtenbach, R., Wiesen, P., Rodler, J., Sturm, P., McCrae, I., Sjödin, \AA., and Baltensberger, U.: Aerosol and NOx emission factors and submicron particle number size distributions in two road tunnels with different traffic regimes, Atmos. Chem. Phys. Discuss., 5, 5127–5166, 2005b. Janhäll. S., Jonsson, \AA. M., Molnár, P., Svensson, E., and Hallquist, M.: Size resolved traffic emission factors of submicrometer particles, Atmos. Environ., 38, 4331–4340, 2004. Ketzel, M., W\aahlin, P., Kristensson, A., Swietlicki, E., Berkowicz, R., Nielsen, O. J., and Palmgren, F.: Particle size distribution and particle mass measurements at urban, near-city and rural level in the Copenhagen area and Southern Sweden, Atmos. Chem. Phys., 4, 281–292, 2004. Khalek, I. A., Kittelson, D. B., and Brear, F.: Nanoparticle growth during dilution and cooling of diesel exhaust: experimental investigation and theoretical assessment, SAE technical paper series, No. 2000-01-0515, 2000. Kittelson, D. B.: Engines and nanoparticles: a review, J. Aerosol Sci., 29, 575–588, 1998. Kittelson, D., Johnson, J., Watts, W., Wei, Q., Drayton, M., Paulsen, D., and Bukowiecki, N.: Diesel aerosol sampling in the atmosphere, SAE technical paper series, No. 2000-01-22212, 2000. Kittelson, D. B., Watts, W. F., and Johnson, J. P.: Nanoparticle emissions on Minnesota highways, Atmos. Environ., 38, 9–19, 2004. Lepperhof, G.: Influences on the particle size distribution of diesel particulate emissions, Topics in Catalysis, 16/17(1–4), 2001. Longley, I. D., Gallagher, M. W., Dorsey, J. R., and Flynn, M.: A case study of fine particle concentrations and fluxes measured in a busy street canyon in Manchester, UK, Atmos. Environ., 38, 3595–3603, 2004. Maricq, M., Chase, R., Xu, N., and Laing, P.: The effects of catalytic converter and fuel sulfur level on motor vehicle particle emissions: Light duty vehicle emissions, Environ. Sci. Technol., 36, 283–289, 2002. Maricq, M. and Xu, N.: The effective density and fractal dimension of soot particles from premixed flames and motor vehicle exhaust, J. Aerosol Sci., 35, 1251–1274, 2004. Marjamäki, M., Keskinen, J., Chen, D.-R., and Pui, D. Y. H.: Performance evaluation of the electrical low pressure impactor (ELPI), J. Aerosol Sci., 31(2), 249–261, 2000. Marjamäki, M., Lemmetty, M., and Keskinen, J.: ELPI response and data reduction I: Response functions, Aerosol Sci. Technol., 39, 575–582, 2005. McMurry, P., Wang, X., Park, K., and Ehara, K.: The relationship between mass and mobility for atmospheric particles: A new technique for measuring particle density, Aerosol Sci. Technol., 36, 227–238, 2002. Molnár, P., Janhäll, S., and Hallquist, M.: Roadside measurements of fine and ultrafine particles at a major road north of Gothenburg, Atmos. Environ., 36, 4115–4123, 2002. Mönkkönen, P., Koponen, I., Lehtinen, K. E. J., Hämeri, K., Uma, R., and Kulmala, M.: Measurements in a highly polluted Asian mega city: observations of aerosol number size distribution, modal parameters and nucleation events, Atmos. Chem. Phys., 5, 57–66, 2005. Park, K., Cao, F., Kittelson, D., and McMurry, P.: Relationship between particle mass and mobility for diesel exhaust particles, Environ. Sci. Technol., 37, 577–583, 2003. Pirjola, L., Paasonen, P., Pfeiffer, D., Hussein, T., Hämeri, K., Koskentalo, T., Virtanen, A., Rönkkö, T., Keskinen, J., and Pakkanen, T.: Dispersion of particles and trace gases nearby a city highway: mobile laboratory measurements in Finland, Atmos. Environ., 40, 867–879, 2006. Pirjola, L., Parviainen, H., Hussein, T., Valli, A., Hämeri, K., Aalto, P., Virtanen, A., Keskinen, J., Pakkanen, T. A., Mäkelä, T., and Hillamo, R. E.: "Sniffer" – a novel tool for chasing vehicles and measuring traffic pollutants, Atmos. Environ., 38, 3625–3635, 2004. Ristimäki, J., Virtanen, A, Marjamäki, M., Rostedt, A., and Keskinen, J.: On-line measurement of size distribution and effective density of submicron aerosol particles, J. Aerosol Sci., 33, 1541–1557, 2002. Ristimäki, J., Keskinen, J., Virtanen A., Maricq, M., and Aakko, P.: Cold temperature PM emissions measurement: Method evaluation and application to light duty vehicles, Environ. Sci. Technol., 39, 9424–9430, 2005. Rose, D., Wehner, B., Ketzel, M., Engler, C., Voigtländer, J., Tuch, T., and Wiedensohler, A.: Atmospheric number size distributions of soot particles and estimation of emission factors, Atmos. Chem. Phys., 6, 1021–1031, 2006. Rönkkö, T., Virtanen , A., Vaaraslahti, K., Keskinen, J., Pirjola, L., and Lappi, M.: Effect of dilution conditions and driving parameters on nucleation mode particles in diesel exhaust: Laboratory and on-road study, Atmos. Environ., 40, 2893–2901, 2006. Sakurai, H., Tobias, H., Park, K., Zarling, D., Doherty, K. S., Kittelson, D. B., McMurry, P. H., and Ziemann, P.: On-line determination of diesel nanoparticle composition and volatility, Atmos. Environ., 37, 1199–1210, 2003a. Sakurai, H., Park, K., McMurry, P., Zarling, D. D., Kittelson, D. B., and Ziemann, P.: Size-Dependent mixing characteristics of volatile and nonvolatile components in diesel exhaust aerosols, Environ. Sci. Technol., 37, 5487–5495, 2003b. Stein, S. W., Turpin, B. J., Cai, X. P., Huang, P. F., and McMurry, P. H.: Measurements of relative humidity-dependent bounce and density for atmospheric particles using tandem-DMA-impactor technique, Atmos. Environ., 28, 1739–1746, 1994. Tunved, P., Hansson, H.-C., Kulmala, M., Aalto, P., Viisanen, Y., Karlsson, H., Kristensson, A., Swietlicki, E., Dal Maso, M., and Komppula, M.: One year boundary layer aerosol size distribution data from five Nordic background stations, Atmos. Chem. Phys., 3, 2183–2205, 2003. Vaaraslahti, K., Virtanen, A., Ristimäki, J., and Keskinen, J.: Nucleation mode formation in heavy-duty diesel exhaust with and without particulate filter, Environ. Sci. Technol., 38, 4884–4890, 2004. Van Dingenen, R., Raes, F., Putaud, J.-P., Baltensberger, U., Charron, A., Facchini, M.-C., Decesari, S., Fuzzi, S., Gehrig, R., Hansson, H.-C., Harrison, R. M., Hüglin, R., Jones, A. M., Laj, P., Lorbeer, G., Maenhaut, W., Palmgren, F., Querol, X., Rodriquez, S., Schneider, J., ten Brink, H., Tunved, P., Torseth, K., Wehner, B., Weingartner, E., Wiedensohler, A., and W\aahlin, P.: A European aerosol phenomenology – 1: physical characteristics of particulate matter at kerbside, urban, rural and background areas in Europe, Atmos. Environ., 38, 2561–2577, 2004. Virtanen, A., Marjamäki, M., Ristimäki, J., and Keskinen, J.: Fine particle losses in electrical low-pressure impactor, J. Aerosol Sci., 32, 389–401, 2001. Virtanen, A., Ristimäki, J., and Keskinen, J.: Method for measuring effective density and fractal dimension of aerosol agglomerates, Aerosol Sci. Technol., 38, 437–446, 2004a. Virtanen, A., Ristimäki, J., Vaaraslahti, K., and Keskinen J.: Effect of engine load on diesel soot particles, Environ. Sci. Technol., 38, 2551–2556, 2004b. Vogt, R., Sheer, V., Casati, R., and Benter, T.: On-road measurement of particle emission in the exhaust plume of a diesel passenger car, Environ. Sci. Technol., 37, 4070–4076, 2003. Wehner, B., Birmili, W., Gnauk, T., and Wiedensohler, A.: Particle number size distribution in a street canyon and their transformation into the urban air background: measurements and a simple model study, Atmos. Environ., 36, 2215–2223, 2002. Wehner, B. and Wiedensohler, A.: Long term measurements of submicron urban aerosols: statistical analysis for correlations with meteorological conditions and trace gases, Atmos. Chem. Phys., 3, 867–879, 2003. Williams, P. I., Gallagher, M. W., Choularton, T. W., Coe, H., Bower, K. N., and McFiggans, G.: Aerosol development and interaction in an urban plume, Aerosol Sci. Technol., 32, 120–126, 2000. W\aahlin, P., Palmgren, F., and Van Dingenen, R.: Experimental studies of ultra fine particles in streets and the relationship to traffic, Atmos. Environ., Suppl. 1, 35, 63–69, 2001.