A new inorganic atmospheric aerosol phase equilibrium model (UHAERO)
A variety of thermodynamic models have been developed to predict inorganic\ngas-aerosol equilibrium. To achieve computational efficiency a number\nof the models rely on a priori specification of the phases present\nin certain relative humidity regimes. Presented here is a new computational\nmodel, named UHAERO, that is both efficient and rigorously computes\nphase behavior without any a priori specification. The computational\nimplementation is based on minimization of the Gibbs free energy\nusing a primal-dual method, coupled to a Newton iteration. The mathematical\ndetails of the solution are given elsewhere. The model computes deliquescence\nbehavior without any a priori specification of the relative humidities\nof deliquescence. Also included in the model is a formulation based\non classical theory of nucleation kinetics that predicts crystallization\nbehavior. Detailed phase diagrams of the sulfate/nitrate/ammonium/water\nsystem are presented as a function of relative humidity at 298.15\nK over the complete space of composition.