Solid state and sub-cooled liquid vapour pressures of substituted dicarboxylic acids using Knudsen Effusion Mass Spectrometry (KEMS) and Differential Scanning Calorimetry

摘要

Solid state vapour pressures of a selection of atmospherically importantsubstituted dicarboxylic acids have been measured using Knudsen EffusionMass Spectrometry (KEMS) over a range of 20 K (298–318 K). Enthalpies offusion and melting points obtained using Differential Scanning Calorimetry(DSC) were used to obtain sub-cooled liquid vapour pressures. They have beencompared to estimation methods used on the E-AIM website. These methods areshown to poorly represent – OH groups in combination with COOH groups.Partitioning calculations have been performed to illustrate the impact ofthe different estimation methods on organic aerosol mass compared to the useof experimental data.