AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Images Reveal That Atmospheric Particles Can Undergo Liquid-Liquid Phase Separations
Yuan You, LINDSAY RENBAUM-WOLFF, Marc Carreras-Sospedra, Sarah J. Hanna, Naruki Hiranuma, Saeid Kamal, Mackenzie Smith, Xiaolu Zhang, Rodney Weber, John Shilling, Donald Dabdub, Scot Martin, Allan Bertram, University of British Columbia
Abstract Number: 482 Working Group: Aerosol Chemistry
Abstract A large fraction of submicron atmospheric particles contain both organic material and inorganic salts. As the relative humidity cycles in the atmosphere, these mixed particles can undergo a range of phase transitions, possibly including liquid-liquid phase separation. If liquid-liquid phase separation occurs, the gas-particle partitioning of atmospheric semi-volatile organic compounds, the scattering and absorption of solar radiation, and the uptake of reactive gas species on atmospheric particles may be affected. Here, using optical and fluorescence microscopy, we present images that show the coexistence of two non-crystalline phases in particles generated from samples collected on multiple days in Atlanta, Georgia, and in particles generated in the laboratory using simulated atmospheric conditions. These results show that atmospheric particles can undergo liquid-liquid phase separations. Applying these new results in a model analysis representative of the Atlanta region, we find that liquid-liquid phase separation can result in increased concentrations of gas-phase NO$_3 and N$_2O$_5 due to decreased particle uptake of N$_2O$_5 in this region.