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| Titel |
Attribution of aerosol light absorption to black carbon, brown carbon, and dust in China – interpretations of atmospheric measurements during EAST-AIRE |
| VerfasserIn |
M. Yang, S. G. Howell, J. Zhuang, B. J. Huebert |
| 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 ; 9, no. 6 ; Nr. 9, no. 6 (2009-03-20), S.2035-2050 |
| Datensatznummer |
250007092
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| Publikation (Nr.) |
 copernicus.org/acp-9-2035-2009.pdf |
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| Zusammenfassung |
| Black carbon, brown carbon, and mineral dust are three of the most important
light absorbing aerosols. Their optical properties differ greatly and are
distinctive functions of the wavelength of light. Most optical instruments
that quantify light absorption, however, are unable to distinguish one type
of absorbing aerosol from another. It is thus instructive to separate total
absorption from these different light absorbers to gain a better
understanding of the optical characteristics of each aerosol type. During the
EAST-AIRE (East Asian Study of Tropospheric Aerosols: an International
Regional Experiment) campaign near Beijing, we measured light scattering
using a nephelometer, and light absorption using an aethalometer and a
particulate soot absorption photometer. We also measured the total mass
concentrations of carbonaceous (elemental and organic carbon) and inorganic
particulates, as well as aerosol number and mass distributions. We were able
to identify periods during the campaign that were dominated by dust, biomass
burning, fresh (industrial) chimney plumes, other coal burning pollution, and
relatively clean (background) air for Northern China. Each of these air
masses possessed distinct intensive optical properties, including the single
scatter albedo and Ångstrom exponents. Based on the wavelength-dependence
and particle size distribution, we apportioned total light absorption to
black carbon, brown carbon, and dust; their mass absorption efficiencies at
550 nm were estimated to be 9.5, 0.5 (a lower limit value), and
0.03 m2/g, respectively. While agreeing with the common consensus that
black carbon is the most important light absorber in the mid-visible, we
demonstrated that brown carbon and dust could also cause significant
absorption, especially at shorter wavelengths. |
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