Seminar

Abstract

Studies of the processes that govern the physical and chemical transformation of aerosol particles are crucial for improving our understanding of the properties of atmospheric aerosol. In particular, the equilibrium state is governed by hygroscopicity, the vapour pressures of semi-volatile organic components, and mixing state. Aerosol optical tweezers can provide a method for isolating single particles, or multiple particles of distinct composition for comparison. When combined with cavity enhanced Raman spectroscopy, particle size, composition and morphology can be characterised in detail. We will first examine how such an approach can allow an examination of the equilibrium state of aerosol. Measurements of the chemical aging of mixed component aerosol (oleic acid/sodium chloride/water) by ozone will then be reported. Finally, a novel approach for probing the kinetics of the mass transfer accompanying condensation or evaporation of water will be described and first measurements reported.