AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
On the Importance of New Particle Formation Events as a Source for Cloud Condensation Nuclei in an Urban Environment
ANNA WONASCHUETZ, Julia Burkart, Anselm Demattio, Carmen Dameto de Espana, Robert Wagner, Georg Reischl, Gerhard Steiner, Regina Hitzenberger, University of Vienna
Abstract Number: 233 Working Group: Urban Aerosols
Abstract New particle formation (NPF) events have been observed in many remote, urban and rural environments. The newly-formed particles are suspected to contribute significantly to cloud condensation nuclei (CCN) concentrations, after growing into the appropriate size range. Due to the relative lack of long-term CCN measurements, quantifications of this souce often rely on CCN concentrations calculated from the size distributions alone. In this calculation, the choice of activation diameter is crucial. In this study, we combine size distribution and CCN measurements from a period of several years (10 months of overlapping measurements) to quantify the contribution of NPF events to CCN concentrations. The measurements were taken at an urban background location in Vienna, Austria. Consistent with other locations, NPF events occur most frequently in the warm season (23% of all days in summer), suggesting the largest contribution in that season. Previous results from the same location have shown that the estimate of the activation diameter from these measurements strongly depends on the assumed mixing state of the aerosol (Burkart et al., 2011, 2012). Here, we investigate the importance of the NPF source for CCN based on different estimates of the activation diameter, and compare it to other factors (local sources, meteorological conditions) influencing CCN concentrations.