In:
Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 23, No. 7 ( 2023-04-14), p. 4463-4488
Abstract:
Abstract. We present a novel technique that elucidates the
mechanism of the formation of small aerosolizable salt particles from salty
frozen samples. We demonstrated that CsCl may be a suitable probe for
sea salts due to its similar subzero properties and sublimation outcomes:
CsCl substantially increased the visibility of the salt both during and
after ice sublimation. Hence, we identified the factors that, during the
sublimation of a frozen salty solution, are important in generating fine
salt particles as a possible source of salt aerosol. The number, size, and
structure of the particles that remain after ice sublimation were
investigated with respect to the concentration of the salt in the sample,
the freezing method, and the sublimation temperature. The last-named aspect
is evidently of primary importance for the preference of fine salt crystals
over a large compact piece of salt; we showed that the formation of
small salt particles is generally restricted if the brine is liquid during
the ice sublimation, i.e. at temperatures higher than the eutectic
temperature (Teu). Small salt particles that might be a source of
atmospheric aerosols were formed predominantly at temperatures below
Teu, and their structures strongly depended on the concentration of the
salt. For example, the sublimation of those samples that exhibited a concentration of less than
0.05 M often produced small aerosolizable isolated particles that are readily able to
be windblown. Conversely, the sublimation of 0.5 M samples led to the
formation of relatively stable and largely interconnected salt structures.
Our findings are in good agreement with other laboratory studies which have
unsuccessfully sought salt aerosols from, for example, frost flowers at
temperatures above Teu. This study offers an explanation of the
previously unexplored behaviour.
Type of Medium:
Online Resource
ISSN:
1680-7324
DOI:
10.5194/acp-23-4463-2023
DOI:
10.5194/acp-23-4463-2023-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2023
detail.hit.zdb_id:
2092549-9
detail.hit.zdb_id:
2069847-1
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