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Measuring black carbon spectral extinction in the visible and infrared
Author(s) -
Smith A. J. A.,
Peters D. M.,
McPheat R.,
Lukanihins S.,
Grainger R. G.
Publication year - 2015
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2015jd023564
Subject(s) - aerosol , carbon black , soot , extinction (optical mineralogy) , single scattering albedo , spectrometer , absorption (acoustics) , analytical chemistry (journal) , optics , infrared , chemistry , particle size distribution , particle (ecology) , carbon fibers , particle size , materials science , combustion , physics , environmental chemistry , natural rubber , oceanography , organic chemistry , composite number , composite material , geology
This work presents measurements of the spectral extinction of black carbon aerosol from 400 nm to 15 μm. The aerosol was generated using a Miniature Combustion Aerosol Standard soot generator and then allowed to circulate in an aerosol cell where its extinction was measured using a grating spectrometer in the visible and a Fourier transform spectrometer in the infrared. Size distribution, number concentration, and mass extinction cross sections have also been obtained using single‐particle aerosol samplers. A mean mass extinction cross section at 550 nm of 8.3 ± 1.6 m 2 g −1 is found which, assuming a reasonable single scatter albedo of 0.2, corresponds to a mass absorption cross section of 6.6 ± 1.3 m 2 g −1 . This compares well with previously reported literature values. Computer analysis of electron microscope images of the particles provides independent confirmation of the size distribution as well as fractal parameters of the black carbon aerosol. The aerosol properties presented in this work are representative of very fresh, uncoated black carbon aerosol. After atmospheric processing of such aerosols (which could include mixing with other constituents and structural changes), different optical properties would be expected.