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| Titel |
Direct aerosol chemical composition measurements to evaluate the physicochemical differences between controlled sea spray aerosol generation schemes |
| VerfasserIn |
D. B. Collins, D. F. Zhao, M. J. Ruppel, O. Laskina, J. R. Grandquist, R. L. Modini, M. D. Stokes, L. M. Russell, T. H. Bertram, V. H. Grassian, G. B. Deane, K. A. Prather |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 7, no. 11 ; Nr. 7, no. 11 (2014-11-06), S.3667-3683 |
| Datensatznummer |
250115943
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| Publikation (Nr.) |
 copernicus.org/amt-7-3667-2014.pdf |
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| Zusammenfassung |
| Controlled laboratory studies of the physical and chemical properties of sea
spray aerosol (SSA) must be under-pinned by a physically and chemically
accurate representation of the bubble-mediated production of nascent SSA
particles. Bubble bursting is sensitive to the physico-chemical properties of
seawater. For a sample of seawater, any important differences in the SSA
production mechanism are projected into the composition of the aerosol
particles produced. Using direct chemical measurements of SSA at the
single-particle level, this study presents an intercomparison of three
laboratory-based, bubble-mediated SSA production schemes: gas forced through
submerged sintered glass filters ("frits"), a pulsed plunging-waterfall
apparatus, and breaking waves in a wave channel filled with natural
seawater. The size-resolved chemical composition of SSA particles produced
by breaking waves is more similar to particles produced by the plunging
waterfall than those produced by sintered glass filters. Aerosol generated
by disintegrating foam produced by sintered glass filters contained a larger
fraction of organic-enriched particles and a different size-resolved
elemental composition, especially in the 0.8–2 μm dry diameter
range. Interestingly, chemical differences between the methods only emerged
when the particles were chemically analyzed at the single-particle level as
a function of size; averaging the elemental composition of all particles
across all sizes masked the differences between the SSA samples. When dried,
SSA generated by the sintered glass filters had the highest fraction of
particles with spherical morphology compared to the more cubic structure
expected for pure NaCl particles produced when the particle contains
relatively little organic carbon. In addition to an intercomparison of
three SSA production methods, the role of the episodic or "pulsed" nature of
the waterfall method on SSA composition was under-taken. In organic-enriched
seawater, the continuous operation of the plunging waterfall resulted in the
accumulation of surface foam and an over-expression of organic matter in SSA
particles compared to those produced by a pulsed plunging waterfall.
Throughout this set of experiments, comparative differences in the SSA
number size distribution were coincident with differences in aerosol
particle composition, indicating that the production mechanism of SSA exerts
important controls on both the physical and chemical properties of the
resulting aerosol with respect to both the internal and external mixing
state of particles. This study provides insight into the inextricable
physicochemical differences between each of the bubble-mediated SSA
generation mechanisms tested and the aerosol particles that they produce,
and also serves as a guideline for future laboratory studies of SSA
particles. |
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