 |
| Titel |
Modeling kinetic partitioning of secondary organic aerosol and size distribution dynamics: representing effects of volatility, phase state, and particle-phase reaction |
| VerfasserIn |
R. A. Zaveri, R. C. Easter, J. E. Shilling, J. H. Seinfeld |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 10 ; Nr. 14, no. 10 (2014-05-27), S.5153-5181 |
| Datensatznummer |
250118736
|
| Publikation (Nr.) |
 copernicus.org/acp-14-5153-2014.pdf |
|
|
|
|
|
| Zusammenfassung |
| This paper describes and evaluates a new framework for modeling kinetic
gas-particle partitioning of secondary organic aerosol (SOA) that takes into
account diffusion and chemical reaction within the particle phase. The
framework uses a combination of (a) an analytical quasi-steady-state
treatment for the diffusion–reaction process within the particle phase for
fast-reacting organic solutes, and (b) a two-film theory approach for slow-
and nonreacting solutes. The framework is amenable for use in regional and
global atmospheric models, although it currently awaits specification of the
various gas- and particle-phase chemistries and the related physicochemical
properties that are important for SOA formation. Here, the new framework is
implemented in the computationally efficient Model for Simulating Aerosol
Interactions and Chemistry (MOSAIC) to investigate the competitive growth
dynamics of the Aitken and accumulation mode particles. Results show that
the timescale of SOA partitioning and the associated size distribution
dynamics depend on the complex interplay between organic solute volatility,
particle-phase bulk diffusivity, and particle-phase reactivity (as
exemplified by a pseudo-first-order reaction rate constant), each of which
can vary over several orders of magnitude. In general, the timescale of SOA
partitioning increases with increase in volatility and decrease in bulk
diffusivity and rate constant. At the same time, the shape of the aerosol
size distribution displays appreciable narrowing with decrease in volatility
and bulk diffusivity and increase in rate constant. A proper representation
of these physicochemical processes and parameters is needed in the next
generation models to reliably predict not only the total SOA mass, but also
its composition- and number-diameter distributions, all of which together
determine the overall optical and cloud-nucleating properties. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|