Organic aerosols account for a substantial fraction of total aerosol mass and have significant impacts on the warming and cooling of the atmosphere that have yet to be fully defined. In most cases, aerosols scatter radiation leading to an overall cooling effect. However, certain classes of compounds such as HULIS, nitrogen- and sulfur containing species, soot, and products from biomass burning have been found to contribute to the absorption of radiation, leading to atmospheric warming. The aerosols in this study were previously collected on filters from the top of Glen Tower A at Towson University. These filters were divided into small sections so that multiple analyses can be performed. The filters are sonicated using a solvent of 50/50 DCM/MeOH, filtered, and dried down using a gentle stream of N<sub>2</sub>. The samples are then reconstituted in 5 mL of the 50/50 DCM/MeOH solution and the absorptive properties are measured using UV-Vis photospectrometry. We find significant absorption in both the visible, 400 nm-700 nm, and near UV regions, 200 nm-400 nm, of the spectrum corresponding to absorption from black carbon (BC) and brown carbon (BrC), respectively. To quantify the absorptive properties, the mass absorption coefficient (MAC) for each filter is determined. We present seasonal trends in the absorptive properties and correlate the absorptive properties with known tracer species using ultra performance liquid chromatography coupled with mass spectrometry (UPLC/MS).

Absorptive properties of atmospheric aerosols collected in Towson, MD

252nd National Meeting (2016)

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