AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Single Particle Diversity and Its Impact on Heterogeneous Reactivity during the SOAS Field Campaign
ANDREW AULT, Amy Bondy, Rebecca Craig, Rachel O'Brien, Ryan Moffet, Bingbing Wang, Alexander Laskin, Mary Gilles, Kerri Pratt, Victor Nhliziyo, Steve Bertman, Paul Shepson, University of Michigan
Abstract Number: 139 Working Group: Air Quality and Climate in the Southeast US: Insights from Recent Measurement Campaigns
Abstract Atmospheric aerosols have contributed to a cooling trend in the southeast United States over the last century, but a great deal of uncertainty remains regarding how individual particle composition and reactivity impact direct scattering and absorption of solar radiation. Samples were collected at the Centreville, Alabama site during the Southern Oxidant and Aerosol Study (SOAS) from June-July 2013. Single particle measurements using an array of microscopy and spectroscopy techniques were used to identify sources and monitor how particles were modified by condensation, coagulation, and heterogeneous reactions. These analyses provide detailed information on particle size, morphology, internal structure, elemental composition, and the functional groups present. A high degree of variability was observed between and within populations of particles from different sources (secondary organic aerosol (SOA), soot, sea spray, mineral dust, etc.). Particles with a thick SOA coating had unique features related to phase and secondary uptake that led to a complex internal structure. Sea spray particles were identified via ratios of inorganic ions and were present at greater concentrations than expected for the inland Centreville site, with interesting secondary chemistry involving nitrate and sulfate formation. The secondary reactions and internal structure of particles in the Southeast U.S. have the potential to play an important role in water uptake, scattering, absorption, and cloud nucleation properties of the particles, which significant impact climate.