Applicability of condensation particle counters to measure atmospheric clusters
1Department of Physics, University of Helsinki, Finland
2Institute for Atmospheric Physics, J. Gutenberg-University Mainz, Mainz, Germany
3Max Planck Institute for Chemistry, Particle Chemistry Department, Mainz, Germany
4School of Physics & Centre for Climate and Air Pollution Studies, Environmental Change Institute, National University of Ireland, Galway, Ireland
*also at: Helsinki Institute of Physics, Helsinki, Finland
**now at: Earth and Sun Systems Laboratory, Atmospheric Chemistry Division, National Center for Atmospheric Research, Boulder, USA
***now at: Institute for Atmosphere and Environment, J. W. Goethe-University Frankfurt, Frankfurt am Main, Germany
****now at: Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA, USA
Abstract. This study presents an evaluation of a pulse height condensation particle counter (PH-CPC) and an expansion condensation particle counter (E-CPC) in terms of measuring ambient and laboratory-generated molecular and ion clusters. Ambient molecular cluster concentrations were measured with both instruments as they were deployed in conjunction with an ion spectrometer and other aerosol instruments in Hyytiälä, Finland at the SMEAR II station between 1 March and 30 June 2007. The observed cluster concentrations varied and ranged from some thousands to 100 000 cm−3. Both instruments showed similar (within a factor of ~5) concentrations. An average size of the detected clusters was approximately 1.8 nm. As the atmospheric measurement of sub 2-nm particles and molecular clusters is a challenging task, we conclude that most likely we were unable to detect the smallest clusters. Nevertheless, the reported concentrations are the best estimates to date for minimum cluster concentrations in a boreal forest environment.
Sipilä, M., Lehtipalo, K., Kulmala, M., Petäjä, T., Junninen, H., Aalto, P. P., Manninen, H. E., Kyrö, E.-M., Asmi, E., Riipinen, I., Curtius, J., Kürten, A., Borrmann, S., and O'Dowd, C. D.: Applicability of condensation particle counters to measure atmospheric clusters, Atmos. Chem. Phys., 8, 4049-4060, doi:10.5194/acp-8-4049-2008, 2008.