Articles | Volume 7, issue 15
Atmos. Chem. Phys., 7, 4081–4094, 2007
https://doi.org/10.5194/acp-7-4081-2007
Atmos. Chem. Phys., 7, 4081–4094, 2007
https://doi.org/10.5194/acp-7-4081-2007

  03 Aug 2007

03 Aug 2007

Evaluation and modeling of the size fractionated aerosol particle number concentration measurements nearby a major road in Helsinki – Part II: Aerosol measurements within the SAPPHIRE project

T. Hussein1,2, J. Kukkonen3, H. Korhonen3,4, M. Pohjola3, L. Pirjola1,5, D. Wraith6, J. Härkönen3, K. Teinilä3, I. K. Koponen1,7, A. Karppinen3, R. Hillamo3, and M. Kulmala1 T. Hussein et al.
  • 1University of Helsinki, Department of Physical Sciences, Finland
  • 2Stockholm University, Department of Applied Environmental Science, Sweden
  • 3Finnish Meteorological Institute, Air Quality Research, Finland
  • 4Institute for Atmospheric Science, School of Earth and Environment, University of Leeds, UK
  • 5Helsinki Polytechnic, Department of Technology, Finland
  • 6School of Mathematical Science, Queensland University of Technology, Brisbane, Australia
  • 7Department of Chemistry, University of Copenhagen, Denmark

Abstract. This study presents an evaluation and modeling exercise of the size fractionated aerosol particle number concentrations measured nearby a major road in Helsinki during 23 August–19 September 2003 and 14 January–11 February 2004. The available information also included electronic traffic counts, on-site meteorological measurements, and urban background particle number size distribution measurement. The ultrafine particle (UFP, diameter<100 nm) number concentrations at the roadside site were approximately an order of magnitude higher than those at the urban background site during daytime and downwind conditions. Both the modal structure analysis of the particle number size distributions and the statistical correlation between the traffic density and the UFP number concentrations indicate that the UFP were evidently from traffic related emissions. The modeling exercise included the evolution of the particle number size distribution nearby the road during downwind conditions. The model simulation results revealed that the evaluation of the emission factors of aerosol particles might not be valid for the same site during different time.

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