Identifying solid-aqueous-phase transitions in atmospheric aerosols. II. Acidic solutions

Sudhakar Potukuchi, Anthony S. Wexler

Research output: Contribution to journalArticle

48 Citations (Scopus)

Abstract

Atmospheric aerosols are often found to be acidic. Predicting the composition of these multi-component aerosols as a function of relative humidity is important in estimating their water content, phase state and acidity. In this work, a computational method that was previously developed and applied to neutral acidity solutions to determine deliquescence relative humidities is extended to acidic solutions. Three sets of acid aerosol compositions are analyzed: H+NH4 +HSO4 -SO4 2-NO3 -, H+NH4 +HSO4 -SO4 2-Cl- and H+NH4NO3 -Cl-. Solubility products are used to determine phase state and water activity at saturation. Activity coefficients are predicted using the recently developed mole-fraction-based thermodynamic model of Clegg and coworkers, along with Pitzer's-molality-based method. Partial dissociation of bisulfate ion, HSO4 - = H+ + SO4 2-, is considered explicitly. For each set of components, water activities at deliquescence are plotted as a function of composition. Trajectories are included that show variation in the composition of the aqueous phase in a multiphase aerosol as a function of relative humidity.

Original languageEnglish (US)
Pages (from-to)3357-3364
Number of pages8
JournalAtmospheric Environment
Volume29
Issue number22
StatePublished - Nov 1995
Externally publishedYes

Fingerprint

Atmospheric aerosols
phase transition
relative humidity
Phase transitions
aerosol
Aerosols
Atmospheric humidity
acidity
Chemical analysis
Acidity
aerosol composition
activity coefficient
Activity coefficients
solubility
Computational methods
thermodynamics
water content
trajectory
saturation
Water content

Keywords

  • acid aerosols
  • activity coefficients
  • bisulfate equilibrium
  • Deliquescence
  • Gibbs free energy
  • phase transitions
  • thermodynamic equilibrium
  • water activity

ASJC Scopus subject areas

  • Environmental Science(all)
  • Atmospheric Science
  • Pollution
  • Earth and Planetary Sciences(all)

Cite this

Identifying solid-aqueous-phase transitions in atmospheric aerosols. II. Acidic solutions. / Potukuchi, Sudhakar; Wexler, Anthony S.

In: Atmospheric Environment, Vol. 29, No. 22, 11.1995, p. 3357-3364.

Research output: Contribution to journalArticle

Potukuchi, Sudhakar ; Wexler, Anthony S. / Identifying solid-aqueous-phase transitions in atmospheric aerosols. II. Acidic solutions. In: Atmospheric Environment. 1995 ; Vol. 29, No. 22. pp. 3357-3364.
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