Thermodynamic Properties of Aqueous Aerosols to High Supersaturation: II--A Model of the System Na+-Cl--NO-3-SO24-H2O at 298.15 K

A mole-fraction-based thermodynamic model is used to represent available activity data, salt solubilities, and electrodynamic balance measurements for aqueous NaCI, Na2S04, NaN03 and their mixtures at 298.15 K. The results are presented as fitted ion-interaction parameters and equilibrium constants. These enable ion and solvent activities, and saturation with respect to five possible solid phases (NaCI, NaN03 , Na2S04 ʹ10H20, Na2S04ʹ and NaN03 ʹ Na2S04ʹ H 20) to be calculated for aU mixture compositions to relative humidities of :::;; 60%, and to high degrees of supersaturation with respect to the dissolved salts. Extension of the model to other systems is discussed.