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| Titel |
Cloud condensation nuclei (CCN) activity of aliphatic amine secondary aerosol |
| VerfasserIn |
X. Tang, D. Price, E. Praske, D. N. Vu, K. Purvis-Roberts, P. J. Silva, D. R. Cocker III, A. Asa-Awuku |
| 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 ; 14, no. 12 ; Nr. 14, no. 12 (2014-06-17), S.5959-5967 |
| Datensatznummer |
250118813
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| Publikation (Nr.) |
 copernicus.org/acp-14-5959-2014.pdf |
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| Zusammenfassung |
| Aliphatic amines can form secondary aerosol via oxidation with atmospheric
radicals (e.g., hydroxyl radical and nitrate radical). The particle can
contain both secondary organic aerosol (SOA) and inorganic salts. The ratio
of organic to inorganic materials in the particulate phase influences aerosol
hygroscopicity and cloud condensation nuclei (CCN) activity. SOA formed from
trimethylamine (TMA) and butylamine (BA) reactions with hydroxyl radical (OH)
is composed of organic material of low hygroscopicity (single hygroscopicity
parameter, κ, ≤ 0.25). Secondary aerosol formed from the tertiary
aliphatic amine (TMA) with N2O5 (source of nitrate radical,
NO3) contains less volatile compounds than the primary aliphatic amine
(BA) aerosol. As relative humidity (RH) increases, inorganic amine salts are formed as a result
of acid–base reactions. The CCN activity of the humid TMA–N2O5
aerosol obeys Zdanovskii, Stokes, and Robinson (ZSR) ideal mixing rules. The
humid BA + N2O5 aerosol products were found to be very
sensitive to the temperature at which the measurements were made within the
streamwise continuous-flow thermal gradient CCN counter; κ ranges
from 0.4 to 0.7 dependent on the instrument supersaturation (ss) settings.
The variance of the measured aerosol κ values indicates that simple
ZSR rules cannot be applied to the CCN results from the primary aliphatic
amine system. Overall, aliphatic amine aerosol systems' κ ranges
within 0.2 < κ < 0.7. This work indicates that aerosols
formed via nighttime reactions with amines are likely to produce hygroscopic
and volatile aerosol, whereas photochemical reactions with OH produce
secondary organic aerosol of lower CCN activity. The contributions of
semivolatile secondary organic and inorganic material from aliphatic amines
must be considered for accurate hygroscopicity and CCN predictions from
aliphatic amine systems. |
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