Chemical Characterization of Individual Sea Spray Aerosol Particles from the Arctic and North Atlantic Regions

JESSICA MIRRIELEES, Rachel Kirpes, Amanda Grannas, Vanessa Boschi, Nurun Nahar Lata, Swarup China, Patricia Matrai, Andrew Ault, Kerri Pratt, University of Michigan

     Abstract Number: 37
     Working Group: Remote and Regional Atmospheric Aerosol

Abstract
Sea spray aerosol particles (SSA) are produced by wave-breaking in surface seawater. Nascent SSA consist of a core, composed primarily of sodium chloride, which is often coated in organic materials. The chemical composition of SSA is influenced by the elemental ratios of seawater ions, the production of organic compounds by the marine biological community, and atmospheric aging. SSA composition influences local atmospheric chemistry, and it has been demonstrated that measurements of individual salt-containing aerosol particles are necessary for closing the gap between modelled and observed production of ClNO2, a source of reactive chloride in the atmosphere.

Variations in SSA chemical composition may result from the status of the marine microbial community. The production of organic material in the local seawater increases during a phytoplankton bloom, though the effect on SSA composition is unclear. The production of SSA in the Arctic is predicted to increase as global temperatures continue to rise. Chemical characterization of SSA in the Arctic is necessary for constraining the consequences of this growing source of aerosol particles.

To this end, ambient SSA particles were sampled near Utqiaġvik, AK, from onboard an icebreaker in the High Arctic, and from a North Atlantic coastal site (East Boothbay, ME). SSA particles were also generated using a marine reference tank with water sampled from a coastal North Atlantic location (East Boothbay, ME). Another series of marine aerosol generation experiments were carried out onboard an icebreaker using water sampled from the High Arctic.

Aerosol particles were collected onto substrates using a Micro-Orifice Uniform Deposition Impactor (MOUDI) or a Davis Rotating-Drum Unit for Monitoring (DRUM). Thousands of individual aerosol particles from each location were subsequently analyzed using electron microscopy with energy-dispersive x-ray analysis, Raman microspectroscopy, and optical-photothermal infrared microspectroscopy in order to gain insight into chemical properties of SSA particles from different environments.