Light absorbing properties of brown carbon generated from pyrolytic combustion of household biofuels

Abstract

The light absorption properties of brown carbon aerosols generated in a lab scale experiment from wood (Magnifera indica) and dung cake were studied. Mie theory along with experimentally derived values for imaginary refractive index was used to estimate mass absorption coefficient for the samples. It was observed that for both wood and dung cake major portion of brown carbon were generated above 150°C. The light absorbing properties of brown carbon from wood depended on temperature of pyrolysis which was not the case for dung cake. The spectral dependence of absorption for brown carbon samples was estimated in terms of Absorption Angstrom Exponent and found to be greater than 2. The brown carbon aerosols from dung cake pyrolysis were having twice the light absorbing potential (in the wavelength range 280 nm to 750 nm) than brown carbon emitted from mango tree wood pyrolytic combustion.