AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Partitioning and Selectivity of Organic Molecules in Nascent Sea Spray Aerosol
RICHARD COCHRAN, Thilina Jayarathne, Olga Laskina, Camille Sultana, Christopher Lee, Kimberly Prather, Elizabeth Stone, Vicki Grassian, University of Iowa
Abstract Number: 203 Working Group: Aerosol Chemistry
Abstract Atmospheric aerosols have long been known to have both direct and indirect impacts on the Earth’s energy balance (i.e., radiative forcing). Sea spray aerosol (SSA) are a major component and have recently been shown to not only be composed of sea salt (i.e., NaCl) but are rather a complex and variable mixture of inorganic and organic compounds as well as biological components. While the organic fraction of SSA has been shown to be size-dependent, the molecular composition of this fraction and how the transfer of the organic species from the sea water to SSA occurs are still unclear. In addition, correlating ocean chemistry to the composition of SSA collected in the field is difficult due to the influence of secondary atmospheric processes in marine environments. This limits the ability of current models to predict the extent of the organic fraction in SSA across the globe and its overall impact on radiative forcing. In this work the molecular composition of the organic fraction of nascent sea spray generated during a waveflume mesocosm experiment was investigated using high resolution mass spectrometry. The levels of naturally derived organic components in SSA were found to depend on SSA particle size, indicating that size-selective mechanisms are involved in the transfer of organic molecules from the bulk seawater to SSA. To further investigate the influence of the chemical and physical properties on the enrichment of organics, a novel technique was used to simulate the generation of SSA under controlled laboratory conditions. Using a representative body of compounds (fatty acids and dicarboxylic acids), enrichment in SSA was found to be affected by the presence of inorganic salts and dependent on the surface activities of the individual acids.