Strong spectral dependence of light absorption by organic carbon particles formed by propane combustion

M. Schnaiter, M. Gimmler, I. Llamas, C. Linke, C. Jäger, H. Mutschke
2006 Atmospheric Chemistry and Physics Discussions  
We have measured the extinction and absorption cross sections of carbon particles emitted by a propane diffusion flame both in an aerosol chamber and on sizesegregated samples deposited on optical windows. The absorption cross section, the single scattering albedo and theÅngström exponent show drastic dependencies both 5 on the C/O ratio and on the particle size. This is interpretated as being due to the appearance of nucleation modes of smaller organic particles at higher C/O ratios, which
more » ... O ratios, which were detected by SMPS measurements and partially by TEM analysis. The spectral range of the validity of the absorption power-law (Ångström exponent) model is investigated by vacuum ultraviolet extinction measurements. These measurements give 10 also indications for a preferentially aromatic nature of the OC component of the flame products. It is well known that BC aerosol is the most efficient absorbing aerosol in the at-1842 ACPD Abstract Introduction Conclusions References Tables Figures Back Close Full Screen / Esc Printer-friendly Version Interactive Discussion EGU mosphere with a mass-specific absorption cross section (σ abs ) in the visible spectral region of about 7.5(±1.2) m 2 /g (Bond and Bergstrom, 2006) . In several laboratory and field studies it was found that BC aerosol emitted from high-temperature combustion processes has a low σ abs spectral dependence of about ∼λ −1 (Schnaiter et al., 2003; Kirchstetter et al., 2004) . The mass specific and spectral absorption properties of OC 5 Abstract 25 1844 Abstract ACPD Abstract ACPD Abstract ACPD
doi:10.5194/acpd-6-1841-2006 fatcat:athf25w2gjcwnihw3pzzj7v5aa