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| Titel |
Laboratory-generated primary marine aerosol via bubble-bursting and atomization |
| VerfasserIn |
E. Fuentes, H. Coe, D. Green, G. Leeuw, G. McFiggans |
| 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 ; 3, no. 1 ; Nr. 3, no. 1 (2010-02-05), S.141-162 |
| Datensatznummer |
250000820
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| Publikation (Nr.) |
 copernicus.org/amt-3-141-2010.pdf |
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| Zusammenfassung |
A range of bubble and sea spray aerosol generators has been tested in the laboratory
and compared with oceanic measurements from the literature. We have shown that the
method of generation has a significant influence on the properties of the
aerosol particles produced. Hence, the validity of a generation system to mimic
atmospheric aerosol is dependent on its capacity for generating bubbles and particles
in a realistic manner. A bubble-bursting aerosol generator which produces bubbles by
water impingement was shown to best reproduce the oceanic bubble spectral shapes,
which confirms previous findings.
Two porous bubblers and a plunging-water jet system were tested as bubble-bursting
aerosol generators for comparison with a standard nebulizer. The methods for aerosol
production were evaluated by analysing the bubble spectrum generated by the bubble-bursting
systems and the submicron size distribution, hygroscopicity and cloud condensation
nucleus activity of the aerosols generated by the different techniques. Significant
differences in the bubble spectrum and aerosol properties were observed when using
different aerosol generators.
The aerosols generated by the different methods exhibited similar hygroscopicity and
cloud condensation nucleus activity behaviour when a sample of purely inorganic salts
was used as a parent seawater solution; however, significant differences in the aerosol
properties were found when using samples of filtered natural seawater enriched with
biogenic organics. The presence of organics in the aerosol caused suppression of the
growth factor at humidities above 75% RH and an increase in the critical supersaturation
with respect to the generation from artificial seawater devoid of organics. The extent of
the effect of organics on the aerosol properties varied depending on the method of particle
production. The results of this work indicate that the aerosol generation mechanism affects
the particles organic enrichment, thus the behaviour of the produced aerosols strongly depends
on the laboratory aerosol generator employed.
Comparison between bubble lifetimes in several laboratory simulations and the oceanic conditions
indicated that it would require a considerable extension of the dimensions of the currently used
bubble-bursting laboratory systems in order to replicate the characteristic oceanic bubble
lifetimes. We analyzed the implications derived from the reduced bubble residence times in
scaled systems, regarding marine surfactants adsorption on rising bubbles, and found that
adsorption equilibrium is reached on a timescale much shorter than the bubble lifetime in
small-scale laboratory generators. This implies that adsorption of marine surface-active
material is not limited by surfactant transport to the bubble surface. |
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