Atmospheric particle formation events at Värriö measurement station in Finnish Lapland 1998-2002 H. Vehkamäki1, M. Dal Maso1, T. Hussein1, R. Flanagan1,4, A. Hyvärinen2, J. Lauros1, P. Merikanto1, M. Mönkkönen1, K. Pihlatie1, K. Salminen2, L. Sogacheva1, T. Thum2, T. M. Ruuskanen1, P. Keronen1, P. P. Aalto1, P. Hari3, K. E. J. Lehtinen1, Ü Rannik1, and M. Kulmala1 1Department of Physical Sciences, P.O. Box 64, 00014 University of Helsinki, Finland 2Finnish Meteorological Institute, P.O Box 503, 00101 Helsinki, Finland 3Department of Forest Ecology, P.O. Box 27, 00014 University of Helsinki, Finland 4Dep. of Experimental Physics and Environmental Change Institute, National Univ. of Ireland, Galway, University Road Galway, Ireland
Abstract. During the calendar years 1998-2002, 147 clear 8nm diameter particle
formation events have been identified at the SMEAR I station in
Värriö, northern Finland. The events have been classified in detail
according to the particle formation rate, growth rate, event starting time,
different trace gas concentrations and pre-existing particle concentrations
as well as various meteorological conditions. The frequency of particle
formation and growth events was highest during the spring months between
March and May, suggesting that increasing biological activity might produce
the precursor gases for particle formation. The apparent 8nm particle
formation rates were around 0.1 /cm3s, and they were uncorrelated with
growth rates that varied between 0.5 and 10nm/h. The air masses with
clearly elevated sulphur dioxide concentrations (above 1.6ppb) came, as
expected, from the direction of the Nikel and Monschegorsk smelters. Only 15
formation events can be explained by the pollution plume from these sources.
Citation: Vehkamäki, H., Dal Maso, M., Hussein, T., Flanagan, R., Hyvärinen, A., Lauros, J., Merikanto, P., Mönkkönen, M., Pihlatie, K., Salminen, K., Sogacheva, L., Thum, T., Ruuskanen, T. M., Keronen, P., Aalto, P. P., Hari, P., Lehtinen, K. E. J., Rannik, Ü, and Kulmala, M.: Atmospheric particle formation events at Värriö measurement station in Finnish Lapland 1998-2002, Atmos. Chem. Phys., 4, 2015-2023, doi:10.5194/acp-4-2015-2004, 2004.