Morphology and Composition of Insoluble Brown Carbon from Biomass Burning

Biomass burning (BB) is a primary source of brown carbon (BrC) in the atmosphere. In the present work, for the first time, the application of an impinger for BrC collection was investigated by conducting BB in a home-built setup. UV-vis, fluorescence, and IR measurements indicated that BrC samples collected by the impinger method have the same properties as those collected by the quartz filter method. In addition to exhibiting good BrC collection performance, the impinger was proven to be effective in concentrating methanol-insoluble substances from the smoke plume. Although elemental analysis and IR spectroscopy revealed that the insoluble substances were mainly composed of plant fibers, the fluorescence emission results showed the presence of BrC, and STEM analysis revealed that BrC was characterized by particles strung on wire-like plant fibers.