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| Titel |
Uptake of HNO3 to deliquescent sea-salt particles: a study using the short-lived radioactive isotope tracer 13N |
| VerfasserIn |
C. Guimbaud, F. Arens, L. Gutzwiller, H. W. Gäggeler, M. Ammann |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 2, no. 4 ; Nr. 2, no. 4 (2002-10-08), S.249-257 |
| Datensatznummer |
250000625
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| Publikation (Nr.) |
 copernicus.org/acp-2-249-2002.pdf |
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| Zusammenfassung |
| The uptake of
HNO3 to deliquescent airborne sea-salt particles (RH = 55%, P =
760 torr, T = 300 K) at concentrations from 2 to 575 ppbv is measured in an aerosol
flow tube using 13N as a tracer. Small particles
(<approx> 70 nm diameter) are used in order to minimize the effect of diffusion in the gas phase on the mass transfer. Below 100
ppbv, an uptake coefficient (gupt) of 0.50 ± 0.20 is derived. At higher concentrations,
the uptake coefficient decreases along with the consumption of aerosol chloride. Data
interpretation is further supported by using the North American Aerosol Inorganics
Model (AIM), which predicts the aqueous phase activities of ions and the gas-phase
partial pressures of H2O,
HNO3, and HCl at equilibrium for the
NaCl/HNO3/H2O
system. These simulations show that the low concentration data are obtained far from
equilibrium, which implies that the uptake coefficient derived is equal to the mass
accommodation coefficient under these conditions. The observed uptake coefficient
can serve as input to modeling studies of atmospheric sea-salt aerosol chemistry. The
main sea-salt aerosol burden in the marine atmosphere is represented by coarse mode
particles (> 1 µm diameter). This implies that diffusion in the gas-phase is the limiting
step to HNO3
uptake until the sea-salt has been completely processed. |
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