10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
An Integrated Approach to Connecting the Chemical and Physical Properties of Aerosol
JAMES F. DAVIES, Michael Jacobs, Kevin Wilson, University of California, Riverside
Abstract Number: 47 Working Group: Aerosol Chemistry
Abstract Our ability to fully understand the effect of aerosols in the atmosphere requires a complete description of their physical and chemical state. Due to the highly oxidizing conditions in the atmosphere, aerosol particles are subject to heterogeneous oxidation, leading to their composition evolving over time. As composition evolves, so too do associated physical properties and characteristics, such as viscosity, hygroscopicity, surface tension, and diffusion. These factors regulate the ability of aerosols to act as sources of cloud condensation nuclei, influence their interactions with incoming solar radiation, and play an important role in the way aerosol affect air quality and human health.
Analytical techniques such as mass spectrometry and Raman/IR spectroscopy are powerful methods applied to measure the evolving chemical composition of aerosols and droplets. Single particle techniques, such as optical tweezers and electrodynamic balances, have been successful in measuring physical properties of aerosol particles, such as surface tension and hygroscopicity. The ability to combine these two types of measurement in a single experiment to resolve how physical properties change with an evolving sample composition could provide a fascinating new insight into how aerosol behave in the atmosphere.
Here, I report the coupling of a single particle levitator (a linear-quadrupole electrodynamic balance) to a high-resolution mass spectrometer.1 Using electrospray-based ionization methods, the exact mass composition of single micron-sized droplets may be measured. Additionally, the physical properties of the droplets may be measured through the use of established methods, such as coalescence, isotope-exchange and humidity-cycling.2 From these data, the physical characteristics of an aerosol can be directly linked to its chemical composition, providing a molecular-level insight into the factors that regulate the dynamics of aerosols in the atmosphere.
(1) Jacobs, M. I.; Davies, J. F.; Lee, L.; Davis, R. D.; Houle, F.; Wilson, K. R. Anal. Chem.2017, 89 (22), 12511–12519.
(2) Davies, J. F.; Wilson, K. R. Anal. Chem.2016, 88, 2361–2366.