CaltechAUTHORS
Published September 1, 2025 | Version Published
Journal Article Open

A diagonal volatility basis set to assess the condensation of organic vapors onto particles

Creators

  • 1. ROR icon Carnegie Mellon University
  • 2. ROR icon University of Chicago
  • 3. ROR icon Goethe University Frankfurt
  • 4. ROR icon Paul Scherrer Institute
  • 5. ROR icon University of Helsinki
  • 6. ROR icon University of Eastern Finland
  • 7. ROR icon Sun Yat-sen University
  • 8. ROR icon University of Cambridge
  • 9. ROR icon P.N. Lebedev Physical Institute of the Russian Academy of Sciences
  • 10. ROR icon Moscow Institute of Physics and Technology
  • 11. ROR icon Universität Innsbruck
  • 12. ROR icon European Organization for Nuclear Research
  • 13. ROR icon Finnish Meteorological Institute
  • 14. Aerodyne Inc, Billerica, MA, USA
  • 15. ROR icon University of Colorado Boulder
  • 16. ROR icon University of Vienna
  • 17. ROR icon TU Wien
  • 18. ROR icon California Institute of Technology

Abstract

We present a “diagonal” Volatility Basis Set (dVBS) comparing gas-phase concentrations of oxygenated organic molecules (OOM) to their condensed-phase mass fractions. This permits closure of vapor concentrations with particle composition constrained by particle growth rates, allowing the contributions of quasi non-volatile condensation, equilibrium partitioning, and reactive uptake to be separated. The dVBS accommodates both equilibrium and dynamical (growth) conditions. Growth implies an association between gas and particle concentrations governed by a “condensation line” that is set by the particle growth rate, which fixes the total (excess) concentration of condensible vapors. The condensation line defines an infeasible region of high particle mass fraction and low gas concentration; under steady-state growth conditions, compounds cannot appear in this infeasible region without being formed by condensed-phase chemistry. We test the dVBS with observations from the CLOUD experiment at CERN using data from a FIGAERO I− Chemical Ionization Mass Spectrometer measuring vapors directly and particle composition via temperature programmed desorption from a filter. A dVBS analysis finds that data from an α-pinene + O3 run at 243 K are consistent with volatility driven condensation forming the large majority of particle mass, with no compounds clearly within the infeasible region.

Copyright and License

© 2025 The Author(s). Published by the Royal Society of Chemistry. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.

Acknowledgement

This work was supported by: grants AGS1447056, AGS1439551, AGS1531284, AGS1801574, AGS1801897, AGS2132089, AGS2215489, AGS2431817, AGS2215527 and CHE2336463 from the U.S. National Science Foundation; the Wallace Research Foundation; the CMU Scott Institute for Energy Innovation; grant 42205108 from National Natural Science Foundation of China; project VRG22-003 from the Vienna Science and Technology Fund (WWF); grants PZ00P2_216181 and 200021_213071 from the Swiss National Foundation; and grants 346371 and 364229 from the Research Council of Finland.

Data Availability

Data for all figures in this paper are available on the CERN Zenodo server.

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Additional details

Identifiers

PMCID
PMC12314873
PMID
40756074

Related works

Describes
Journal Article: PMC12314873 (PMCID)
Journal Article: 40756074 (PMID)

Funding

National Science Foundation
AGS1447056
National Science Foundation
AGS1439551
National Science Foundation
AGS1531284
National Science Foundation
AGS1801574
National Science Foundation
AGS1801897
National Science Foundation
AGS2132089
National Science Foundation
AGS2215489
National Science Foundation
AGS2431817
National Science Foundation
AGS2215527
National Science Foundation
CHE2336463
Wallace Research Foundation
Carnegie Mellon University
CMU Scott Institute for Energy Innovation -
National Natural Science Foundation of China
42205108
Vienna Science and Technology Fund
VRG22-003
Swiss National Science Foundation
PZ00P2_216181
Swiss National Science Foundation
200021_213071
Research Council of Finland
346371
Research Council of Finland
364229

Dates

Accepted
2025-07-20
Available
2025-07-21
Published online

Caltech Custom Metadata

Caltech groups
Division of Chemistry and Chemical Engineering (CCE)
Publication Status
Published