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Titel |
Measurement of ambient aerosol hydration state at Great Smoky Mountains National Park in the southeastern United States |
VerfasserIn |
N. F. Taylor, D. R. Collins, C. W. Spencer, D. H. Lowenthal, B. Zielinska, V. Samburova, N. Kumar |
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 ; 11, no. 23 ; Nr. 11, no. 23 (2011-12-07), S.12085-12107 |
Datensatznummer |
250010239
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Publikation (Nr.) |
copernicus.org/acp-11-12085-2011.pdf |
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Zusammenfassung |
We present results from two field deployments of a unique tandem
differential mobility analyzer (TDMA) configuration with two primary
capabilities: identifying alternative stable or meta-stable ambient aerosol
hydration states associated with hysteresis in aerosol hydration behavior
and determining the actual Ambient hydration State (AS-TDMA). This data set
is the first to fully classify the ambient hydration state of aerosols
despite recognition that hydration state significantly impacts the roles of
aerosols in climate, visibility and heterogeneous chemistry. The AS-TDMA was
installed at a site in eastern Tennessee on the border of Great Smoky
Mountains National Park for projects during the summer of 2006 and winter of
2007–2008. During the summer, 12% of the aerosols sampled in continuous
AS-TDMA measurements were found to posses two possible hydration states
under ambient conditions. In every case, the more hydrated of the possible
states was occupied. The remaining 88% did not posses multiple possible
states. In continuous measurements during the winter, 49% of the aerosols
sampled possessed two possible ambient hydration states; the remainder
possessed only one. Of those aerosols with multiple possible ambient
hydration states, 65% occupied the more hydrated state; 35% occupied
the less hydrated state. This seasonal contrast is supported by differences
in the fine particulate (PM2.5) composition and ambient RH as measured
during the two study periods. In addition to seasonal summaries, this work
includes case studies depicting the variation of hydration state with
changing atmospheric conditions. |
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