Atmospheric particle formation events at Värriö measurement station in Finnish Lapland 1998-2002

• Main Authors: 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, Kulmala, M.
• Other Authors: Department of Physical Sciences Helsinki, University of Helsinki, Department of Experimental Physics and Environmental Change Institute, National University of Ireland Maynooth (Maynooth University), Finnish Meteorological Institute (FMI), Forest Ecology and Management Helsinki, Department of Forest Sciences Helsinki, Faculty of Agriculture and Forestry Helsinki, University of Helsinki-University of Helsinki-Faculty of Agriculture and Forestry Helsinki, University of Helsinki-University of Helsinki
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2004
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; Northern Finland; Lapland
• Online Access: https://hal.archives-ouvertes.fr/hal-00295537; https://hal.archives-ouvertes.fr/hal-00295537/document; https://hal.archives-ouvertes.fr/hal-00295537/file/acp-4-2015-2004.pdf

International audience 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 /cm 3 s, 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.