Charged and total particle formation and growth rates during EUCAARI 2007 campaign in Hyytiälä 1Department of Physics, University of Helsinki, P.O. Box 64, 00014 Helsinki, Finland
2Finnish Meteorological Institute, Research and Development, P.O. Box 503, 00101 Helsinki, Finland
Received: 22 Dec 2008 – Published in Atmos. Chem. Phys. Discuss.: 25 Feb 2009 – Published: 22 Jun 2009Abstract. Despite the fact that frequent aerosol formation has been observed in
various locations in the atmosphere, the overall magnitude of the new
particle formation as a particle source is still unclear. In order to
understand the particle formation and growth processes, we investigate the
magnitudes of the particle formation and growth rates at the size where the
real atmospheric nucleation and activation occurs. The relative contribution
of neutral and charged particles to the new particle formation rate is also
studied. The data include particle and ion number size distributions and
total particle concentration measurements at a boreal forest site in
Hyytiälä, Finland, during the spring 2007 EUCAARI field campaign.
The total and charged particle formation rates differed from each other by
approximately an order of magnitude. The median formation rates of 2 nm total and charged particles were 0.65 cm−3 s−1 and
0.03 cm−3 s−1, respectively. The median growth rates of particles in
size classes 1.3–3, 3–7 and 7–20 nm were 1.9, 3.6 and 4.2 nm h−1,
respectively. The calculated ion-ion recombination rates were about the same
order of magnitude as the ion-induced formation rates. The results indicate
that the ion-induced nucleation involving the ion-ion recombination
products, i.e. ion mediated nucleation, contributes approximately 10% to
the boreal forest new particle formation events.
Citation: Manninen, H. E., Nieminen, T., Riipinen, I., Yli-Juuti, T., Gagné, S., Asmi, E., Aalto, P. P., Petäjä, T., Kerminen, V.-M., and Kulmala, M.: Charged and total particle formation and growth rates during EUCAARI 2007 campaign in Hyytiälä, Atmos. Chem. Phys., 9, 4077-4089, doi:10.5194/acp-9-4077-2009, 2009.