Thermodynamic properties of aqueous aerosols to high supersaturation .2. A model of the system Na+-Cl--NO3--SO42--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 NaCl, Na2SO4, NaNO3 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 (NaCl, NaNO3, Na2SO4 . 10H(2)O, Na2SO4, and NaNO3 . Na2SO4 . H2O) to be calculated for all mixture compositions to relative humidities of less than or equal to 60%, and to high degrees of supersaturation with respect to the dissolved salts. Extension of the model to other systems is discussed. (C) 1997 American Association for Aerosol Research.