Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published October 1982 | public
Journal Article

Thermodynamic prediction of the water activity, NH₄NO₃ dissociation constant, density and refractive index for the NH₄NO₃-(NH₄)₂SO₄-H₂O system at 25°C


The thermodynamic properties, water activity, density and refractive index of NH₄NO₃-(NH₄)₂SO₄-H₂O aerosols are estimated from binary solution data and existing mixing rules. Particle growth is shown to be predictable from the particle composition, the NH₄NO₃-(NH₄)₂SO₄-H₂O phase diagram and the water activity calculation technique of C.L. Kusik and H.P. Meissner (1978, A.I.Ch. E. Symp. 173, 14–20). Good agreement between the theoretical predictions and the experimental measurements of I.N. Tang et al. (1981, Atmospheric Environment15, 2463–2471), J. Thudium (1978,Pageoph. 116, 130–148) and H.H. Emons and W. Hahn (1970, Wiss Z.12, 129–132) is shown. Also, the effect of (NH₄)₂SO₄ on the relative humidity dependence of the NH₄NO₃ dissociation constant is evaluated.

Additional Information

© 1982 Pergamon Press. First received 24 August 1981 and in final form 18 December 1981. This work was supported by U.S. Environmental Protection Agency grant R806844. We would like to thank James J. Morgan for helpful discussions.

Additional details

August 19, 2023
October 17, 2023