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Measured Saturation Vapor Pressures of Phenolic and Nitro-aromatic Compounds
journal contribution
posted on 2017-03-06, 00:00 authored by Thomas J. Bannan, A. Murray Booth, Benjamin T. Jones, Simon O’Meara, Mark H. Barley, Ilona Riipinen, Carl J. Percival, David ToppingPhenolic and nitro-aromatic compounds
are extremely toxic components
of atmospheric aerosol that are currently not well understood. In
this Article, solid and subcooled-liquid-state saturation vapor pressures
of phenolic and nitro-aromatic compounds are measured using Knudsen
Effusion Mass Spectrometry (KEMS) over a range of temperatures (298–318
K). Vapor pressure estimation methods, assessed in this study, do
not replicate the observed dependency on the relative positions of
functional groups. With a few exceptions, the estimates are biased
toward predicting saturation vapor pressures that are too high, by
5–6 orders of magnitude in some cases. Basic partitioning theory
comparisons indicate that overestimation of vapor pressures in such
cases would cause us to expect these compounds to be present in the
gas state, whereas measurements in this study suggest these phenolic
and nitro-aromatic will partition into the condensed state for a wide
range of ambient conditions if absorptive partitioning plays a dominant
role. While these techniques might have both structural and parametric
uncertainties, the new data presented here should support studies
trying to ascertain the role of nitrogen containing organics on aerosol
growth and human health impacts.