Hygroscopic growth and critical supersaturations for mixed aerosol particles of inorganic and organic compounds of atmospheric relevance

Abstract

Abstract. The organic fraction of atmospheric aerosols contains a multitude of compounds and usually only a small fraction can be identified and quantified. However, a limited number of representative organic compounds can be used to describe the water-soluble organic fraction. In this work, initiated within the EU 5FP project SMOCC, four mixtures containing various amounts of inorganic salts (ammonium sulfate, ammonium nitrate, and sodium chloride) and three model organic compounds (levoglucosan, succinic acid and fulvic acid) were studied. The interaction between water vapor and aerosol particles was studied at different relative humidities: at subsaturation using a hygroscopic tandem differential mobility analyzer (H-TDMA) and at supersaturation using a cloud condensation nuclei spectrometer (CCN spectrometer). Surface tensions as a function of carbon concentrations were measured using a bubble tensiometer. Parameterizations of water activity as a function of molality, based on hygroscopic growth, are given for the pure organic compounds and for the mixtures, indicating van't Hoff factors around 1 for the organics. The Zdanovskii-Stokes-Robinson (ZSR) mixing rule was tested on the hygroscopic growth of the mixtures and it was found to adequately explain the hygroscopic growth for 3 out of 4 mixtures, when the limited solubility of succinic acid is taken into account. One mixture containing sodium chloride was studied and showed a pronounced deviation from the ZSR mixing rule. Critical supersaturations calculated using the parameterizations of water activity and the measured surface tensions were compared with those determined experimentally.

Hygroscopic Growth and Deliquescence of NaCl Nanoparticles Coated with Surfactant AOT

“…12,32 Measured GF values for the mixed particles were approximately consistent with the assumption that the organic and inorganic species adsorb water independently, in accordance with the ZdanovskiiStokes-Robinson (ZSR) model. 33,34 Similar conclusions were reached in studies of water activities above the bulk mixtures of the same compounds. 35,36 The main objective of this work is to test the effect of sparingly soluble organic coatings on hygroscopic properties of NaCl nanoparticles.…”

“…34,36,64,65 The ZSR model assumes that there are no interactions among the different mixture components; therefore, the hygroscopic growth of the internally mixed particles is an appropriately weighed sum of the hygroscopic growth factors of its components. 66 It also assumes an ideal mixing behavior with spherical particles having a shape factor of unity.…”

Design and Validation of a Volatility Hygroscopic Tandem Differential Mobility Analyzer (VH-TDMA) to Characterize the Relationships Between the Thermal and Hygroscopic Properties of Atmospheric Aerosol Particles

“…atmosphere due to the presence of sea-salt and sulphate aerosols (Berg et al 1998;Johnson et al 2004;Putaud et al 2004;Raes et al 2000;Swietlicki et al 1999;Bower et al 2000), while reduced HGF (i.e., <1.1) are found in the urban areas Rissler et al 2005). In most sites, however, H-TDMA studies indicate the simultaneous presence of both a less-hygroscopic and a more hygroscopic particle class, consisting of particles with less and more soluble material, respectively (Svenningsson et al 1992(Svenningsson et al , 1994Zhang et al 1993;Covert and Heintzenberg 1993;Pitchford and McMurry 1994;Kerminem 1997;Swietlicki et al 2000).…”

A Marine Aerosol Reference Tank system as a breaking wave analogue for the production of foam and sea-spray aerosols

“…Several different methods have been used to generate surrogate marine aerosols within enclosed tanks including pressurized atomizers (Svenningsson et al, 2006;Riziq et al, 2007;Saul et al, 2006;McNeill et al, 2006;Braban et al, 2007;Niedermeier et al, 2008;Taketani et al, 2009), forcing air through glass filters or sintered materials (Cloke et al, 1991;Martensson et al, 2003;Sellegri et al, 2006;Keene et al, 2007;Tyree et al, 2007;Wise et al, 2009;Hultin et al, 2010;Fuentes et al, 2010) and by a plunging water jet (Cipriano and Blanchard, 1981;Sellegri et al, 2006;Facchini et al, 2008;Fuentes et al, 2010).…”