Journal cover Journal topic
Atmospheric Measurement Techniques An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 3.248 IF 3.248
  • IF 5-year value: 3.650 IF 5-year 3.650
  • CiteScore value: 3.37 CiteScore 3.37
  • SNIP value: 1.253 SNIP 1.253
  • SJR value: 1.869 SJR 1.869
  • IPP value: 3.29 IPP 3.29
  • h5-index value: 47 h5-index 47
  • Scimago H index value: 60 Scimago H index 60
Volume 11, issue 1 | Copyright
Atmos. Meas. Tech., 11, 49-63, 2018
https://doi.org/10.5194/amt-11-49-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Research article 08 Jan 2018

Research article | 08 Jan 2018

A reference data set for validating vapor pressure measurement techniques: homologous series of polyethylene glycols

Ulrich K. Krieger1, Franziska Siegrist1, Claudia Marcolli1, Eva U. Emanuelsson2, Freya M. Gøbel2, Merete Bilde2, Aleksandra Marsh3, Jonathan P. Reid3, Andrew J. Huisman4, Ilona Riipinen5, Noora Hyttinen6, Nanna Myllys7, Theo Kurtén6, Thomas Bannan8, Carl J. Percival8, and David Topping8 Ulrich K. Krieger et al.
  • 1Institute for Atmospheric and Climate Science, ETH Zürich, 8092 Zürich, Switzerland
  • 2Department of Chemistry, Aarhus University, 8000 Aarhus, Denmark
  • 3School of Chemistry, University of Bristol, BS8 1TS Bristol, UK
  • 4Chemistry Department, Union College, Schenectady, NY 12308, USA
  • 5Department of Environmental Science and Analytical Chemistry, Stockholm University, 106 91 Stockholm, Sweden
  • 6Department of Chemistry, University of Helsinki, 00014 Helsinki, Finland
  • 7Department of Physics, University of Helsinki, 00014 Helsinki, Finland
  • 8Centre for Atmospheric Sciences, School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester, M13 9PL, UK

Abstract. To predict atmospheric partitioning of organic compounds between gas and aerosol particle phase based on explicit models for gas phase chemistry, saturation vapor pressures of the compounds need to be estimated. Estimation methods based on functional group contributions require training sets of compounds with well-established saturation vapor pressures. However, vapor pressures of semivolatile and low-volatility organic molecules at atmospheric temperatures reported in the literature often differ by several orders of magnitude between measurement techniques. These discrepancies exceed the stated uncertainty of each technique which is generally reported to be smaller than a factor of 2. At present, there is no general reference technique for measuring saturation vapor pressures of atmospherically relevant compounds with low vapor pressures at atmospheric temperatures. To address this problem, we measured vapor pressures with different techniques over a wide temperature range for intercomparison and to establish a reliable training set. We determined saturation vapor pressures for the homologous series of polyethylene glycols (H − (O − CH2 − CH2)n − OH) for n = 3 to n = 8 ranging in vapor pressure at 298K from 10−7 to 5×10−2Pa and compare them with quantum chemistry calculations. Such a homologous series provides a reference set that covers several orders of magnitude in saturation vapor pressure, allowing a critical assessment of the lower limits of detection of vapor pressures for the different techniques as well as permitting the identification of potential sources of systematic error. Also, internal consistency within the series allows outlying data to be rejected more easily. Most of the measured vapor pressures agreed within the stated uncertainty range. Deviations mostly occurred for vapor pressure values approaching the lower detection limit of a technique. The good agreement between the measurement techniques (some of which are sensitive to the mass accommodation coefficient and some not) suggests that the mass accommodation coefficients of the studied compounds are close to unity. The quantum chemistry calculations were about 1 order of magnitude higher than the measurements. We find that extrapolation of vapor pressures from elevated to atmospheric temperatures is permissible over a range of about 100K for these compounds, suggesting that measurements should be performed best at temperatures yielding the highest-accuracy data, allowing subsequent extrapolation to atmospheric temperatures.

Publications Copernicus
Download
Short summary
Vapor pressures of low-volatility organic molecules at atmospheric temperatures reported in the literature often differ by several orders of magnitude between measurement techniques. These discrepancies exceed the stated uncertainty of each technique, which is generally reported to be smaller than a factor of 2. We determined saturation vapor pressures for the homologous series of polyethylene glycols ranging in vapor pressure at 298 K from 1E−7 Pa to 5E−2 Pa as a reference set.
Vapor pressures of low-volatility organic molecules at atmospheric temperatures reported in the...
Citation
Share