Thermodynamic modeling of atmospheric aerosols: 0-100% relative humidity

Cari S. Dutcher, Xinlei Ge, Caitlin Asato, Anthony S. Wexler, Simon L. Clegg

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Accurate models of water and solute activities in aqueous atmospheric aerosols are central to predicting aerosol size, optical properties and cloud formation. A powerful method has been recently developed (Dutcher et al. JPC 2011, 2012, 2013) for representing the thermodynamic properties of multicomponent aerosols at low and intermediate levels of RH (< 90%RH) by applying the principles of multilayer sorption to ion hydration in solutions. In that work, statistical mechanics was used to model sorption of a solvent (water), onto each solute or ion in solution as n energetically distinct layers. This corresponds to n hydration layers surrounding each solute molecule. Here, we extend the model to the 100% RH limit and reduce the number of adjustable model parameters, allowing for a unified thermodynamic treatment for a wider range of atmospheric systems. The long-range interactions due to electrostatic screening of ions in solution are included as a mole fraction based Pitzer-Debye-Hückel (PDH) term. Equations for the Gibbs free energy, solvent and solute activity, and solute concentration are derived, yielding remarkable agreement between measured and fitted solute concentration and osmotic coefficients for solutions over the entire 0 to 100% RH range. By relating the values of the energy of sorption in each hydration layer to known short-range Coulombic electrostatic relationships governed by the size and dipole moment of the solute and solvent molecules, it may be possible to reduce the number of parameters for each solute. Modified equations for mixtures that take into account the long range PDH term will also be presented; these equations include no additional parameters.

Original languageEnglish (US)
Title of host publicationAIP Conference Proceedings
Pages441-444
Number of pages4
Volume1527
DOIs
StatePublished - 2013
Event19th International Conference on Nucleation and Atmospheric Aerosols, ICNAA 2013 - Fort Collins, CO, United States
Duration: Jun 23 2013Jun 28 2013

Other

Other19th International Conference on Nucleation and Atmospheric Aerosols, ICNAA 2013
CountryUnited States
CityFort Collins, CO
Period6/23/136/28/13

Fingerprint

humidity
aerosols
solutes
thermodynamics
sorption
hydration
electrostatics
ions
Gibbs free energy
statistical mechanics
water
molecules
dipole moments
screening
thermodynamic properties
moments
optical properties
coefficients
interactions

Keywords

  • Activity coefficients
  • adsorption isotherms
  • Debye-Hückel
  • electrolyte solutions
  • McKay-Perring
  • Zdanovskii-Stokes-Robinson

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Dutcher, C. S., Ge, X., Asato, C., Wexler, A. S., & Clegg, S. L. (2013). Thermodynamic modeling of atmospheric aerosols: 0-100% relative humidity. In AIP Conference Proceedings (Vol. 1527, pp. 441-444) https://doi.org/10.1063/1.4803299

Thermodynamic modeling of atmospheric aerosols : 0-100% relative humidity. / Dutcher, Cari S.; Ge, Xinlei; Asato, Caitlin; Wexler, Anthony S.; Clegg, Simon L.

AIP Conference Proceedings. Vol. 1527 2013. p. 441-444.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Dutcher, CS, Ge, X, Asato, C, Wexler, AS & Clegg, SL 2013, Thermodynamic modeling of atmospheric aerosols: 0-100% relative humidity. in AIP Conference Proceedings. vol. 1527, pp. 441-444, 19th International Conference on Nucleation and Atmospheric Aerosols, ICNAA 2013, Fort Collins, CO, United States, 6/23/13. https://doi.org/10.1063/1.4803299
Dutcher CS, Ge X, Asato C, Wexler AS, Clegg SL. Thermodynamic modeling of atmospheric aerosols: 0-100% relative humidity. In AIP Conference Proceedings. Vol. 1527. 2013. p. 441-444 https://doi.org/10.1063/1.4803299
Dutcher, Cari S. ; Ge, Xinlei ; Asato, Caitlin ; Wexler, Anthony S. ; Clegg, Simon L. / Thermodynamic modeling of atmospheric aerosols : 0-100% relative humidity. AIP Conference Proceedings. Vol. 1527 2013. pp. 441-444
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