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| Titel |
Measuring the atmospheric organic aerosol volatility distribution: a theoretical analysis |
| VerfasserIn |
E. Karnezi, I. Riipinen, S. N. Pandis |
| 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. 9 ; Nr. 7, no. 9 (2014-09-16), S.2953-2965 |
| Datensatznummer |
250115898
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| Publikation (Nr.) |
 copernicus.org/amt-7-2953-2014.pdf |
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| Zusammenfassung |
| Organic compounds represent a
significant fraction of submicrometer atmospheric aerosol mass. Even if most
of these compounds are semi-volatile in atmospheric concentrations, the
ambient organic aerosol volatility is quite uncertain. The most common
volatility measurement method relies on the use of a thermodenuder (TD). The
aerosol passes through a heated tube where its more volatile components
evaporate, leaving the less volatile components behind in the particulate
phase. The typical result of a thermodenuder measurement is the mass fraction
remaining (MFR), which depends, among other factors, on the organic aerosol
(OA) vaporization enthalpy and the accommodation coefficient. We use a new
method combining forward modeling, introduction of "experimental" error,
and inverse modeling with error minimization for the interpretation of TD
measurements. The OA volatility distribution, its effective vaporization
enthalpy, the mass accommodation coefficient and the corresponding
uncertainty ranges are calculated. Our results indicate that existing
TD-based approaches quite often cannot estimate reliably the OA volatility
distribution, leading to large uncertainties, since there are many different
combinations of the three properties that can lead to similar thermograms. We
propose an improved experimental approach combining TD and isothermal
dilution measurements. We evaluate this experimental approach using the same
model, and show that it is suitable for studies of OA volatility in the lab
and the field. |
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