Gas-Particle Uptake and Hygroscopic Growth by Organosulfate Particles

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

5 Scopus Citations
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  • Paul E. Ohno
  • Junfeng Wang
  • Fabian Mahrt
  • Jonathan G. Varelas
  • Eleonora Aruffo
  • Jianhuai Ye
  • Kristian J. Kiland
  • Allan K. Bertram
  • Regan J. Thomson
  • Scot T. Martin


Original languageEnglish
Pages (from-to)2481-2490
Journal / PublicationACS Earth and Space Chemistry
Issue number10
Online published19 Sept 2022
Publication statusPublished - 20 Oct 2022
Externally publishedYes


Organosulfate compounds make up a substantial fraction of the particle mass concentration in some regions of the Earth's atmosphere, and organosulfate particles can have sufficiently high viscosity to limit rates of gas-particle interactions. Viscosity varies with relative humidity (RH). Herein, organosulfate particles were exposed to the gas-phase products of α-pinene photooxidation. The gas-particle partitioning of these species was studied from 15 to 70% RH and <1 to 16 ppb NO at 299 K. The uptake of the α-pinene oxidation products increased with the increase in RH, and higher gas-phase NO concentrations resulted in increased particle-phase concentrations of nitrogen compounds. Particle hygroscopicity was examined by optical microscopy. Hygroscopic growth at elevated RH was sufficient to explain the RH-dependent uptake measurements, and kinetic limitations tied to particle viscosity were not observed. The lack of kinetic limitations combined with the Stokes-Einstein equation implied a viscosity much less than 1 × 106 Pa s. This value is consistent with estimated viscosities based on literature parameterizations for water mass fractions in the particles of at least 0.05 at 15% RH. Overall, these results suggest that organosulfate hygroscopicity plays a key role in their viscosity and hence in regulating gas-particle partitioning, thereby simplifying the treatment of atmospheric chemistry and transport of pollutants in models of the Earth's atmosphere. The role of organosulfates is expected to take on increasing importance for projected future emission trends. © 2022 American Chemical Society.

Research Area(s)

  • aerosol mass spectrometry, aerosol particles, environmental chamber, gas-particle partitioning, hygroscopicity, organosulfates, viscosity

Citation Format(s)

Gas-Particle Uptake and Hygroscopic Growth by Organosulfate Particles. / Ohno, Paul E.; Wang, Junfeng; Mahrt, Fabian et al.
In: ACS Earth and Space Chemistry, Vol. 6, No. 10, 20.10.2022, p. 2481-2490.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review