Light absorption of organic aerosol from pyrolysis of corn stalk: Fid-Bau Portal

Light absorption of organic aerosol from pyrolysis of corn stalk

Li, Xinghua / Chen, Yanju / Bond, Tami C.

AbstractOrganic aerosol (OA) can absorb solar radiation in the low-visible and ultra-violet wavelengths thereby modifying radiative forcing. Agricultural waste burning emits a large quantity of organic carbon in many developing countries. In this work, we improved the extraction and analysis method developed by Chen and Bond, and extended the spectral range of OC absorption. We examined light absorbing properties of primary OA from pyrolysis of corn stalk, which is a major type of agricultural wastes. Light absorption of bulk liquid extracts of OA was measured using a UV–vis recording spectrophotometer. OA can be extracted by methanol at 95%, close to full extent, and shows polar character. Light absorption of organic aerosol has strong spectral dependence (Absorption Ångström exponent = 7.7) and is not negligible at ultra-violet and low-visible regions. Higher pyrolysis temperature produced OA with higher absorption. Imaginary refractive index of organic aerosol (kOA) is 0.041 at 400 nm wavelength and 0.005 at 550 nm wavelength, respectively.

Graphical abstract

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Highlights•We improve the extraction method and extended the spectral range of OC absorption.•We examine light absorption of OA from pyrolysis of corn stalk at three temperature.•Absorption of OA has strong spectral dependence and is not be negligible.•Higher pyrolysis temperature produced OA with higher absorption.•Absorption of OA from pyrolysis of corn stalk and wood appears to some consistency.