HR: 14:55h
AN: A33C-06    [Abstracts]
TI: Sodium Nitrate Particles: Physical and Chemical Properties During Hydration and Dehydration. Implications for aged Sea Salt Aerosols.
AU: Hoffman, R C
EM: rhoffman@uci.edu
AF: Department of Chemistry, University of California, Irvine, CA 92697
AU: * Laskin, A
EM: Alexander.Laskin@pnl.gov
AF: Pacific Northwest National Laboratory, POB 999, K8-88, Richland, WA 99352
AU: Finlayson-Pitts, B J
EM: bjfinlay@uci.edu
AF: Department of Chemistry, University of California, Irvine, CA 92697
AU: Yang, Z
EM: yangz@me.udel.edu
AF: Department of Mechanical Engineering, University of Delaware, Newark, DE 19716
AU: Wang, H
EM: hwang@me.udel.edu
AF: Department of Mechanical Engineering, University of Delaware, Newark, DE 19716
AB: Experiments probing the phase and behavior of NaNO3 particles at different relative humidities, important for elucidating the role these particles play in the chemistry and radiative properties of marine regions, are presented. Changes in NaNO3 particles during hydration were studied using environmental scanning electron microscopy (ESEM) and conventional SEM coupled with energy dispersive X-ray analysis (SEM/EDX). Mixtures of NaNO3 and NaCl, which are typical of partially processed sea salt particles, were also studied. Complementary studies using long path FTIR and FTIR microscopy were carried out to determine the extent of water association with NaNO3 aerosols, and for comparison, NaCl, MgCl2, and NH4NO3, as a function of relative humidity. The combination of these techniques shows that NaNO3 particles exist as unusual metastable, amorphous solids at low relative humidity that undergo continuous hygroscopic growth with increasing relative humidity.
DE: 4801 Aerosols (0305)
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0345 Pollution--urban and regional (0305)
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting