Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 15, 4063-4075, 2015
http://www.atmos-chem-phys.net/15/4063/2015/
doi:10.5194/acp-15-4063-2015
© Author(s) 2015. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
17 Apr 2015
On the derivation of particle nucleation rates from experimental formation rates
A. Kürten1, C. Williamson1, J. Almeida2, J. Kirkby1,2, and J. Curtius1 1Institute for Atmospheric and Environmental Sciences, Goethe University of Frankfurt, 60438 Frankfurt am Main, Germany
2CERN, 1211 Geneva, Switzerland
Abstract. Particle formation rates are usually measured at sizes larger than the critical size at which nucleation occurs. Due to loss of particles during their growth to the detection threshold, the measured formation rate is often substantially lower than the nucleation rate. For this reason a correction needs to be applied in order to determine the nucleation rate from the measured formation rate. Analytical formulae for the correction factor are provided in the literature. However, these methods were derived for atmospheric nucleation measurements and therefore need to be adjusted in order to be applied to chamber nucleation studies. Here we propose an alternative, numerical method that allows precise nucleation rates to be determined in arbitrary experimental environments. The method requires knowledge of the particle size distribution above detection threshold, the particle growth rate, and the particle loss rates as a function of particle size. The effect of self-coagulation, i.e., cluster–cluster collisions, is taken into account in the method.

Citation: Kürten, A., Williamson, C., Almeida, J., Kirkby, J., and Curtius, J.: On the derivation of particle nucleation rates from experimental formation rates, Atmos. Chem. Phys., 15, 4063-4075, doi:10.5194/acp-15-4063-2015, 2015.
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Short summary
The manuscript provides insights into the calculation of new particle formation rates. Generally, formation rates are measured at a diameter which can be substantially larger than the critical size of the newly formed particles. In order to transform the formation rate to a smaller size, a correction needs to be applied. We present a new method to apply this correction which takes into account the effect of self-coagulation.
The manuscript provides insights into the calculation of new particle formation rates....
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