Atmospheric aerosol models for systems including the ions H + , NH 4 + , Na + , SO 4 2− , NO 3 − , Cl − , Br − , and H 2 O

Mole fraction based equations for aqueous phase activities, together with equilibrium constants for the formation of gases and solids, have been combined with a Gibbs free energy minimization algorithm to create equilibrium phase partitioning models of inorganic atmospheric aerosols. The water content, phase state (solid or liquid), and gas/aerosol partitioning are predicted for known ionic composition, relative humidity, and temperature. The models are valid from <200 to 328 K for the subsystems (H + ‐SO 4 2− ‐NO 3 − ‐Cl − ‐Br − ‐H 2 O) and (H + ‐NH 4 + ‐SO 4 2− ‐NO 3 − ‐H 2 O), and 298.15 K only for (H + ‐NH 4 + ‐Na + ‐SO 4 2− ‐NO 3 − ‐Cl − ‐H 2 O). The models involve no simplifying assumptions and…