The browser you are using is not supported by this website. All versions of Internet Explorer are no longer supported, either by us or Microsoft (read more here: https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Please use a modern browser to fully experience our website, such as the newest versions of Edge, Chrome, Firefox or Safari etc.

Constraining the density and complex refractive index of elemental and organic carbon in biomass burning aerosol using optical and chemical measurements

På svenska

Author

  • G. Schkolnik
  • D. Chand
  • A. Hoffer
  • M. O. Andreae
  • C. Erlick
  • Erik Swietlicki
  • Y. Rudich

Summary, in English

The role of biomass burning aerosols in the climate system is still poorly quantified, in part due to uncertainties regarding the optical properties of elemental and organic carbon (EC and OC, respectively), the main constituents of pyrogenic aerosols. In this study, we utilize comprehensive physical and chemical field measurements of biomass burning aerosols in Brazil to constrain the densities and refractive indices (RI) of EC and OC in these particles, by comparing their optically and chemically derived RI. The optically derived effective RI are retrieved from the measured absorption and scattering coefficients using a Mie scattering algorithm, and serve as a reference dataset, while the chemically derived effective RI are calculated from the measured chemical composition using electromagnetic mixing rules. The results are discussed in light of the observed combustion conditions, and in an effort to derive conclusions as to the chemical and optical properties of the usually less well-characterized components of biomass burning aerosols, namely, elemental carbon and organic matter. The best agreement between the optically and chemically derived RI was achieved by assigning a density of rho(EC) = 1.8 g cm(-3) and refractive index RIEC = 1.87 - 0.22i to the EC component, and rho = 0.9 g cm(-3) and RI = 1.4 - 0i to the unidentified organic matter fraction of the particles. These parameters suggest low graphitization levels for the EC, and a dominant proportion of aliphatic compounds in the unidentified organic matter. Combining the density and RI of the unidentified organic matter with the properties of the chemically characterized organic fraction yields rho = 1.1 g cm(-3) and RI = 1.3 - 0i for the total aerosol OC. (c) 2006 Elsevier Ltd. All rights reserved.

Department/s

Publishing year

2007

Language

English

Pages

1107-1118

Publication/Series

Atmospheric Environment

Volume

41

Issue

5

Document type

Journal article

Publisher

Elsevier

Topic

  • Meteorology and Atmospheric Sciences

Keywords

  • aerosol optical properties
  • biomass burning
  • refractive index
  • organic carbon
  • elemental carbons

Status

Published

Research group

  • Aerosol, Nuclear Physics

ISBN/ISSN/Other

  • ISSN: 1352-2310