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| Titel |
Influence of crustal dust and sea spray supermicron particle concentrations and acidity on inorganic NO3− aerosol during the 2013 Southern Oxidant and Aerosol Study |
| VerfasserIn |
H. M. Allen, D. C. Draper, B. R. Ayres, A. Ault, A. Bondy, S. Takahama, R. L. Modini, K. Baumann, E. Edgerton, C. Knote, A. Laskin, B. Wang, J. L. Fry |
| 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 ; 15, no. 18 ; Nr. 15, no. 18 (2015-09-25), S.10669-10685 |
| Datensatznummer |
250120056
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| Publikation (Nr.) |
 copernicus.org/acp-15-10669-2015.pdf |
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| Zusammenfassung |
| Inorganic aerosol composition was measured in the southeastern United
States, a region that exhibits high aerosol mass loading during the summer,
as part of the 2013 Southern Oxidant and Aerosol Study (SOAS) campaign.
Measurements using a Monitor for AeRosols and GAses (MARGA) revealed two
periods of high aerosol nitrate (NO3−) concentrations during the
campaign. These periods of high nitrate were correlated with increased
concentrations of supermicron crustal and sea spray aerosol species,
particularly Na+ and Ca2+, and with a shift towards aerosol with
larger (1 to 2.5 μm) diameters. We suggest this nitrate aerosol
forms by multiphase reactions of HNO3 and particles, reactions that are
facilitated by transport of crustal dust and sea spray aerosol from a source
within the United States. The observed high aerosol acidity prevents the
formation of NH4NO3, the inorganic nitrogen species often dominant
in fine-mode aerosol at higher pH. Calculation of the rate of the
heterogeneous uptake of HNO3 on mineral aerosol supports the conclusion
that aerosol NO3− is produced primarily by this process, and is
likely limited by the availability of mineral cation-containing aerosol surface area. Modeling
of NO3− and HNO3 by thermodynamic equilibrium models (ISORROPIA
II and E-AIM) reveals the importance of including mineral cations in the
southeastern United States to accurately balance ion species and predict
gas–aerosol phase partitioning. |
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