Aerosol thermodynamics of potassium salts, double salts, and water content near the eutectic

James T. Kelly, Anthony S. Wexler, Chak K. Chan, Man N. Chan

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Water uptake by hygroscopic constituents of atmospheric particles has implications for climate and health. This article focuses on three topics related to calculating particle water uptake. First, an electrodynamic balance (EDB) is used to measure water activity for supersaturated binary KNO3 and KCl solutions. The EDB measurements for KNO3 confirm earlier predictions, while those for KCl confirm earlier measurements. Second, our earlier theory for the variation in mutual deliquescence relative humidity (MDRH) with temperature (T) is extended to double salt systems. The MDRH(T) equation for double salt systems reduces to the earlier equation under some conditions, and predictions for two systems are in reasonable agreement with solubility-based calculations. Finally, an approximate treatment of water uptake in the MDRH region (i.e., near the eutectic) is evaluated, and a new approach is developed that accounts for particle composition. The new approach represents predictions of a benchmark model well and eliminates most of the error associated with the earlier method. Although simple treatments of water uptake near the eutectic may introduce error into equilibrium calculations, their use can sometimes be justified based on inherent limitations of aerosol representations in chemistry-transport models. Results of this study can be used to improve calculations of water content in atmospheric aerosol models.

Original languageEnglish (US)
Pages (from-to)3717-3728
Number of pages12
JournalAtmospheric Environment
Volume42
Issue number16
DOIs
StatePublished - May 2008

Fingerprint

water uptake
Eutectics
Water content
Aerosols
Potassium
potassium
thermodynamics
water content
Thermodynamics
Salts
aerosol
salt
relative humidity
electrodynamics
Atmospheric humidity
Electrodynamics
Water
prediction
atmospheric particle
Atmospheric aerosols

Keywords

  • Deliquescence
  • Eutonic
  • Hydrate
  • Potassium
  • Supersaturated

ASJC Scopus subject areas

  • Atmospheric Science
  • Environmental Science(all)
  • Pollution

Cite this

Aerosol thermodynamics of potassium salts, double salts, and water content near the eutectic. / Kelly, James T.; Wexler, Anthony S.; Chan, Chak K.; Chan, Man N.

In: Atmospheric Environment, Vol. 42, No. 16, 05.2008, p. 3717-3728.

Research output: Contribution to journalArticle

Kelly, James T. ; Wexler, Anthony S. ; Chan, Chak K. ; Chan, Man N. / Aerosol thermodynamics of potassium salts, double salts, and water content near the eutectic. In: Atmospheric Environment. 2008 ; Vol. 42, No. 16. pp. 3717-3728.
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