Brown carbon aerosol particles are a main player in global climate change because of their strong absorption and abundance. However, the formation kinetics of brown carbon have not been fully characterized. Secondary organic aerosol reactions between ammonium salts and aldehydes have been implicated in brown carbon formation. Hence, this study focused on the reactions between fresh and reacted ammonium sulfate with glyoxal, methylglyoxal, glycoaldehyde, and hydroxyacetone. A cavity attenuated phase shift single scattering albedo spectrometer (CAPS-ssa) was used to measure aerosol light extinction and light scattering at 450 nm. Aerosol absorbance, calculated from these measurements, was used to determine reaction rates for each of these systems. Results indicate brown carbon products form more quickly in evaporating droplets than in bulk solutions. Knowing that brown carbon forms quickly through these reactions in evaporating droplets will lead to a more accurate global radiation budget of brown carbon.

Single scattering albedo studies of brown carbon formation in evaporating droplets

249th National Meeting (2015)

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