Abstract. The phase state of atmospheric particulate is important to atmospheric
processes, and aerosol radiative forcing remains a large uncertainty in
climate predictions. That said, precise atmospheric phase behavior is
difficult to quantify and observations have shown that “precondensation” of
water below predicted saturation values can occur. We propose a revised
approach to understanding the transition from solid soluble particles to
liquid droplets, typically described as cloud condensation nucleation – a
process that is traditionally captured by Köhler theory, which describes
a modified equilibrium saturation vapor pressure due to (i) mixing entropy
(Raoult's law) and (ii) droplet geometry (Kelvin effect). Given that
observations of precondensation are not predicted by Köhler theory, we
devise a more complete model that includes interfacial forces giving rise to
predeliquescence, i.e., the formation of a brine layer wetting a salt
particle at relative humidities well below the deliquescence point.
Superhydrophobic Sands for the Preservation and Purification of Water