Detailed determination of size- and time-dependent growth rates during new particle formation

Description

INTRODUCTION
The formation of nanoparticles through gas-to-particle conversion is observed throughout the global atmosphere (Kulmala et al., 2004). Nucleation at the critical cluster size of 1-2 nm is often followed by growth (Kulmala et al., 2013), such that the newly formed particles can be of significant climactic relevance through the aerosol indirect effect. In competition to growth, newly formed particles can get lost to preexisting aerosol. This effect is most dominant for particles below 10 nm and in many cases prevents newly formed particles to reach larger sizes. Quantification of nanoparticle growth rates below 10 nm are therefore
crucial in estimating the impact of new particle formation on the global climate (Tröstl et al., 2016).
Some authors report growth rates from ambient or chamber measurements quantified with the appearance time method (Kulmala et al., 2013; Lehtipalo et al., 2014; Tröstl et al., 2016). Unfortunately, this method cannot resolve details in the size and time-dependencies of the observed growth events. Several attempts
have been made in the past to quantify nanoparticle growth rates by solving the aerosol general dynamic equation (GDE) (Lehtinen et al. 2004; Verheggen and Mozurkewich, 2008; Kuang et al., 2012). However, these methods require a high quality of the input data and so far lack detailed intercomparison.
Here we present the development of two new inverse modeling procedures, which have been verified by application to simulated size-distributions. Moreover, we applied both methods to experimental data taken at the NCAR biogenic aerosol chamber.

Period	27 Jun 2017
Event title	20th International Conference on Nucleation and Atmospheric Aerosols
Event type	Conference
Location	Helsinki, FinlandShow on map