The vapor pressures and activities of dicarboxylic acids reconsidered: the impact of the physical state of the aerosol

Abstract

We present vapor pressure data of the C<sub>2</sub> to C<sub>5</sub> dicarboxylic acids deduced from measured evaporation rates of single levitated particles as both, aqueous droplets and solid crystals. The data of aqueous solution particles over a wide concentration range allow us to directly calculate activities of the dicarboxylic acids and comparison of these activities with parameterizations reported in the literature. The data of the pure liquid state acids, i.e. the dicarboxylic acids in their supercooled melt state, exhibit no even-odd alternation in vapor pressure, while the acids in the solid form do. This observation is consistent with the known solubilities of the acids and our measured vapor pressures of the supercooled melt. Thus, the gas/particle partitioning of the different dicarboxylic acids in the atmosphere depends strongly on the physical state of the aerosol phase, the difference being largest for the even acids. <br><br> Our results show also that, in general, measurements of vapor pressures of solid dicarboxylic acids may be compromised by the presence of amorphous fractions, polymorphic forms, crystalline structures with a high defect number, and/or solvent inclusions in the solid material, yielding a higher vapor pressure than the one of the thermodynamically stable crystalline form at the same temperature

Reactions between water-soluble organic acids and nitrates in atmospheric aerosols: Recycling of nitric acid and formation of organic salts

“…[], and Soonsin et al . []. The range of K H values for MA and GA is compiled from the listed references.…”

Determining Aerosol Volatility Parameters Using a “Dual Thermodenuder” System: Application to Laboratory-Generated Organic Aerosols

“…At the same time, there is a discrepancy between the two EDB measurements of a factor of 7. It should be noted that the data reported by Soonsin et al (2010) are derived for particle evaporation at the later stages of particle evaporation (after the initial evaporation phase of several hours). The initial evaporation rate was significantly higher than that during the later stages.…”

“…Several studies (Koponen et al 2007;Soonsin et al 2010;Zardini et al 2006) have shown evidence for the importance of the particle state for aerosol partitioning. Our assumption for laboratory-generated particles is that they are solid.…”

“…These were selected because their volatilities have been characterized using a number of methods (Bilde et al 2003;Booth et al 2010;Bruns et al 2012;Cappa et al 2007;Cerully et al 2014;Chattopadhyay and Ziemann 2005;Davies and Thomas 1960;Faulhaber et al 2009;Ribeiro da Silva et al 1999;Saleh et al 2008;Salo et al 2010;Soonsin et al 2010;Tao and McMurry 1989), as recently reviewed by Bilde et al (2015). In DA volatility experiments, aerosols were generated using a constant output atomizer (TSI Model 3076) from solutions (»0.5% w/v) of deionized water and AA or SA (Sigma Aldrich, >99.0%).…”

Technical Note: Estimating fusion properties for polyacids

“…To describe the partitioning of a compound to the aerosol, its liquid vapor pressure is required. Vapor pressures of polyacids have been measured since decades (Bradley and Cotson, 1953;Arshadi, 1974) but recently work in this area has intensified, with several publications in only this year (Booth et al, 2010(Booth et al, , 2011Frosch et al, 2010;Soonsin et al, 2010;Pope et al, 2010).…”