The role of sulphates and organic vapours in growth of newly formed particles in a eucalypt forest 1ILAQH, Queensland University of Technology, P.O. Box 4233, Brisbane QLD, 4001, Australia
2Div. of Atmospheric Sciences and Geophysics, Department of Physics, University of Helsinki, P.O. Box 64, 00014, Finland
3Laboratory of Atmospheric Chemistry, Paul Scherrer Institut, 5232 Villigen, Switzerland
4ANCAR/ACD, BAI Group, 3450 Mitchell Lane, Boulder, CO 80301, USA
*now at: Laboratory for Energy Systems Analysis, Paul Scherrer Institut, 5232 Villigen, Switzerland
**now at: Physic Department, CERN, 1211, Switzerland
Received: 26 Jun 2009 – Published in Atmos. Chem. Phys. Discuss.: 31 Aug 2009 Abstract. The influence of biogenic particle formation on climate is a well recognised
phenomenon. To understand the mechanisms underlying the biogenic particle
formation, determining the chemical composition of the new particles and
therefore the species that drive the particle production is of utmost
importance. Due to the very small amount of mass involved, indirect
approaches are frequently used to infer the composition. We present here the
results of such an indirect approach by simultaneously measuring volatile and
hygroscopic properties of newly formed particles in a forest environment. It is shown
that the particles are composed of both sulphates and organics, with the
amount of sulphate component strongly depending on the available gas-phase
sulphuric acid, and the organic components having the same volatility and hygroscopicity
as photo-oxidation products of a monoterpene such as α-pinene.
Our findings agree with a two-step process through
nucleation and cluster formation followed by simultaneous growth by
condensation of sulphates and organics that take the particles to
climatically relevant sizes.
Revised: 25 Mar 2010 – Accepted: 26 Mar 2010 – Published: 29 Mar 2010
Citation: Ristovski, Z. D., Suni, T., Kulmala, M., Boy, M., Meyer, N. K., Duplissy, J., Turnipseed, A., Morawska, L., and Baltensperger, U.: The role of sulphates and organic vapours in growth of newly formed particles in a eucalypt forest, Atmos. Chem. Phys., 10, 2919-2926, doi:10.5194/acp-10-2919-2010, 2010.