Correlations between optical, chemical and physical properties of biomass burn aerosols

[1] Aerosols generated from burning different plant fuels were characterized to determine relationships between chemical, optical and physical properties. Single scattering albedo (w) and Angstrom absorption coefficients (aap) were measured using a photoacoustic technique combined with a reciprocal nephelometer. Carbon-to-oxygen atomic ratios, sp hybridization, elemental composition and morphology of individual particles were measured using scanning transmission X-ray microscopy coupled with near-edge X-ray absorption fine structure spectroscopy (STXM/ NEXAFS) and scanning electron microscopy with energy dispersion of X-rays (SEM/EDX). Particles were grouped into three categories based on sp hybridization and chemical composition. Measured w (0.4 1.0 at 405 nm) and aap (1.0 3.5) values displayed a fuel dependence. The category with sp hybridization >80% had values of w (<0.5) and aap ( 1.25) characteristic of light absorbing soot. Other categories with lower sp hybridization (20 to 60%) exhibited higher w (>0.8) and aap (1.0 to 3.5) values, indicating increased absorption spectral selectivity. Citation: Hopkins, R. J., K. Lewis, Y. Desyaterik, Z. Wang, A. V. Tivanski, W. P. Arnott, A. Laskin, and M. K. Gilles (2007), Correlations between optical, chemical and physical properties of biomass burn aerosols, Geophys. Res. Lett., 34, L18806, doi:10.1029/2007GL030502.