 |
| Titel |
Identification and quantification of particle growth channels during new particle formation |
| VerfasserIn |
M. R. Pennington, B. R. Bzdek, J. W. DePalma, J. N. Smith, A.-M. Kortelainen, L. Hildebrandt Ruiz, T. Petäjä, M. Kulmala  , D. R. Worsnop, M. V. Johnston |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 13, no. 20 ; Nr. 13, no. 20 (2013-10-17), S.10215-10225 |
| Datensatznummer |
250085758
|
| Publikation (Nr.) |
 copernicus.org/acp-13-10215-2013.pdf |
|
|
|
|
|
| Zusammenfassung |
| Atmospheric new particle formation (NPF) is a key source of ambient
ultrafine particles that may contribute substantially to the global
production of cloud condensation nuclei (CCN). While NPF is driven by
atmospheric nucleation, its impact on CCN concentration depends strongly on
atmospheric growth mechanisms since the growth rate must exceed the loss
rate due to scavenging in order for the particles to reach the CCN size
range. In this work, chemical composition measurements of 20 nm diameter
particles during NPF in Hyytiälä, Finland, in March–April 2011
permit identification and quantitative assessment of important growth
channels. In this work we show the following: (A) sulfuric acid, a key species
associated with atmospheric nucleation, accounts for less than half of
particle mass growth during this time period; (B) the sulfate content of a
growing particle during NPF is quantitatively explained by condensation of
gas-phase sulfuric acid molecules (i.e., sulfuric acid uptake is
collision-limited); (C) sulfuric acid condensation substantially impacts the
chemical composition of preexisting nanoparticles before new particles have
grown to a size sufficient to be measured; (D) ammonium and sulfate
concentrations are highly correlated, indicating that ammonia uptake is
driven by sulfuric acid uptake; (E) sulfate neutralization by ammonium does
not reach the predicted thermodynamic end point, suggesting that a barrier
exists for ammonia uptake; (F) carbonaceous matter accounts for more than
half of the particle mass growth, and its oxygen-to-carbon ratio
(~ 0.5) is characteristic of freshly formed secondary organic
aerosol; and (G) differences in the overall growth rate from one formation
event to another are caused by variations in the growth rates of all major
chemical species, not just one individual species. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|