AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Optical Properties of Water Soluble Organic Carbon (WSOC) in Atmospheric Aerosols and Fog Waters
JINWEI ZHANG, David Hanigan, Paul Westerhoff, Pierre Herckes, Arizona State University
Abstract Number: 594 Working Group: Aerosol Chemistry
Abstract Water soluble organic carbon (WSOC) is an important part of atmospheric aerosol particles. Despite its abundance, little is known on its optical properties, in particular the absorptivity and how it related to the chemistry and structure of WSOC. Possible transformations by aqueous phase processing are also poorly understood.
Here we present measurements of WSOC absorptivity in the UV-Vis range of a variety of atmospheric aerosols and fog/cloud waters representative of urban, remote and rural areas and collected during different seasons. UV-vis absorptivity by WSOC in aerosols was significantly larger than that in fog waters. When the specific absorptivity (normalized by organic carbon content) was considered, the absorptivity varied only over a small range for any given location. We will also discuss the impact of inorganic species, humidity and pH on WSOC absorptivity and the resulting impact on atmospheric aqueous photochemistry through screening effects.