Charged and total particle formation and growth rates during EUCAARI 2007 campaign in Hyytiälä

H E Manninen,M Kulmala,I Riipinen,P P Aalto,E Asmi,T Yli-Juuti,V.-M Kerminen,T Nieminen,S Gagné,T Petäjä

doi:10.5194/acp-9-4077-2009

H E Manninen, M Kulmala + Show 8 more

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https://doi.org/10.5194/acp-9-4077-2009

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Abstract

Abstract. 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.

Highlights

Aerosol particles affect atmospheric opacity and cloud properties and thereby the climate by influencing the radiation budget in both regional and global scales (Cabada et al., 2004; Lohmann and Feichter, 2005)
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 purpose of this paper is to investigate the magnitude of the particle formation and growth rates close to the size where the real atmospheric nucleation and activation occurs, as well as to investigate the relative contribution of neutral and charged particles to the new particle formation

Summary

Introduction

Aerosol particles affect atmospheric opacity and cloud properties and thereby the climate by influencing the radiation budget in both regional and global scales (Cabada et al., 2004; Lohmann and Feichter, 2005). Particles nucleated and grown in the atmosphere may participate in the cloud formation processes by acting as cloud condensation nuclei (Lihavainen et al, 2003; Kerminen et al, 2005; Kuwata et al, 2008). Formation of atmospheric particles by nucleation of vapors and subsequent growth of the particles by condensation are observed world-wide in various environments (Kulmala et al, 2004a; Kulmala and Kerminen, 2008). Recent model studies suggest that in the atmosphere nucleation may be a globally important source of aerosol particles and cloud condensation nuclei (Spracklen et al, 2006, 2008; Yu et al, 2008). The particle formation characteristics, such as formation and growth rates, can be used as indicators of the relevant processes and participating compounds in the initial formation

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