The phase equilibrium models of inorganic aerosol systems made available on this web site are the results of an ongoing NATO funded project to develop a state-of-the-art chemical thermodynamic model of aerosols of composition H+- NH4+- Na+-SO42- -NO3-- Cl--H2O. The models enable the distribution of water and ions to be calculated between liquid, solid and vapour phases for ambient conditions (temperature, relative humidity) specified by the user.
Calculations of the activities of water and ions present in the aqueous aerosol - the most critical part of the model - utilise the Pitzer, Simonson and Clegg equations (1,2). The current models build on previous applications to aqueous H2SO4 and HNO3, and to their mixtures with HCl and HBr (3-5). Their latest results, incorporated into the models on this site, are the subject of three recently published papers (6,7,9).
The Models can be used in several forms. Three codes are currently available for use:
Model I: H+-SO42- -NO3--Cl-- Br--H2O. This is the stratospheric model of Carslaw et al.
Model II: H+ -NH4+-SO4 2--NO3- -H2O. This is recent work of Clegg and Wexler.
Model III: H+- NH4+-Na+ -SO42--NO3 --Cl--H2O (at 298.15 K only). This is recent work of Clegg and Wexler.
Simon L. Clegg
School of Environmental Sciences
University of East Anglia, Norwich NR4 7TJ, UK.
phone: +44 (0)1603 593815
fax: +44 (0)1603 507719
Summary by 何莉 on 2003-09-26
Last updated by 何莉 on 2003-09-26