Aerosol charging state at an urban site: new analytical approach and implications for ion-induced nucleation
Item
Title (Dublin Core)
Aerosol charging state at an urban site: new analytical approach and implications for ion-induced nucleation
Description (Dublin Core)
The charging state of aerosol populations was determined using an Ion-DMPS in Helsinki, Finland between December 2008 and February 2010. We extrapolated the charging state and calculated the ion-induced nucleation fraction to be around 1.3 % ± 0.4 % at 2 nm and 1.3 % ± 0.5 % at 1.5 nm, on average. We present a new method to retrieve the average charging state for a new particle formation event, at a given size and polarity. We improve the uncertainty assessment and fitting technique used previously with an Ion-DMPS. We also use a new theoretical framework that allows for different concentrations of small ions for different polarities (polarity asymmetry). We extrapolate the ion-induced fraction using polarity symmetry and asymmetry. Finally, a method to calculate the growth rates from the behaviour of the charging state as a function of the particle diameter using polarity symmetry and asymmetry is presented and used on a selection of new particle formation events.
Creator (Dublin Core)
Gagné, S.
Leppä, J.
Petäjä, T.
McGrath, M. J.
Vana, M.
Kerminen, V.-M.
Laakso, L.
Kulmala, M.
Date (Dublin Core)
2018-01-15
Type (Dublin Core)
Text
Format (Dublin Core)
application/pdf
Identifier (Dublin Core)
10.5194/acp-12-4647-2012
https://acp.copernicus.org/articles/12/4647/2012/
Source (Dublin Core)
eISSN: 1680-7324
Language (Dublin Core)
eng
