Both thermodynamic and kinetic approaches are employed to interpret data revealing a hysteresis effect during the growth/evaporation of hygroscopic particles in an ambient solvent vapour. For given thermodynamic parameters and material constants, the deliquescence humidity can be determined from the generalised Gibbs-Kelvin-Köhler and Oswald-Freundlich equations. Additionally employing the quasi-steady nucleation kinetics, we can estimate the efflorescence hu-midity. The predictive power of this approach is demonstrated for the sodium chloride-water system.