Gas-Particle-Partitioning

ModelingToolkit implementation of ammonium nitrate (NH4NO3) gas-aerosol equilibrium from Seinfeld & Pandis (2006), Atmospheric Chemistry and Physics, 2nd ed., Chapter 10, Section 10.4.3. NH4NO3 is a semi-volatile aerosol species whose gas-particle partitioning depends strongly on temperature and relative humidity. The component evaluates three temperature- and humidity-dependent quantities: the natural log of the solid-phase dissociation constant ln(Kp) for NH3(g) + HNO3(g) <-> NH4NO3(s) (Eq. 10.91), the deliquescence relative humidity DRH of NH4NO3 (Eq. 10.88), and a phase indicator that is 1 when the ambient RH exceeds the DRH (aqueous aerosol) and 0 otherwise (solid aerosol). Migrated from Aerosol.jl NH4NO3Equilibrium. Purely algebraic: no differential states, three observed outputs and an empty equations array.

Gas-particle partitioning model for a secondary organic aerosol (SOA) compound that does not interact with preexisting aerosol. The compound condenses as a pure substance once the reacted ROG exceeds a threshold set by the saturation concentration; below the threshold all product remains in the gas phase. From Seinfeld and Pandis (2006), Chapter 14, Section 14.5.2, Equations 14.6–14.18.