Tutorial 10:

Aerosol Particle Thermodynamics

Cari S. Dutcher, University of Minnesota, USA.

Abstract: The chemical thermodynamic properties of the salt, organic, and acid mixtures present in soluble aerosol particles govern the particles’ phase state, water uptake, and gas-particle partitioning, as functions of temperature and relative humidity. In this course, we will cover fundamental thermodynamic properties used to describe atmospheric aerosol particles, such as hygroscopicity and water uptake; activity coefficients and deviation from ideal behavior; solid-liquid-gas chemical partitioning; phase transitions including deliquescence, efflorescence and liquid-liquid separation; and thermodynamics of surfaces, including Kelvin effect, surface tension, surfactants and surface-bulk partitioning.  Bulk and single particle thermodynamic measurement techniques will be reviewed, including isopiestic measurement techniques, electrodynamic balances, optical tweezers, and hydrodynamic traps. Attention will be given to typical sources of error and uncertainty in the measurements, in order to improve the user’s understanding and interpretation of thermodynamic properties. Available modeling approaches and predictive calculators for thermodynamic properties of activity, surface tension, density, phase partitioning, and mixing state will be discussed.

Short bio: Cari S. Dutcher is an Associate Professor of Mechanical Engineering (ME) and Chemical Engineering and Materials Science (CEMS) at the University of Minnesota, Twin Cities, with research interests in aerosol science and multiphase fluids. Cari has served on the American Association for Aerosol Research (AAAR) board of directors, AAAR aerosol physics working group chair, and currently serves as secretary on the AAAR Executive Board.  She has received a number of early faculty awards, including the 3M Non-Tenured Faculty Award, NSF CAREER and AAAR Kenneth T. Whitby Award. Cari received her Ph.D. from the University of California, Berkeley in Chemical Engineering and was a postdoc at the University of California, Davis in the Air Quality Research Center.