Trace gas exchange at the air/water interface: Measurements of mass accommodation coefficients

Abstract

A liquid jet of 90 ~tm diameter and variable length has been utilized to determine absorption rates and, hence, mass accommodation coefficients y, of atmospheric trace gases. The compounds investigated are HC1 (~,~>0.01), HNO 3 (y~>0.01), N205 (~,>~0.005), peroxyacetyl nitrate (y > 0.001), and HONO (~, >/0.005). It is concluded that the absorption of these trace gases by liquid atmospheric water is not significantly retarded by interfacial mass transport. The strengths and limitations of the liquid jet technique for measuring mass accommodation coefficients are explored.

Evaluated kinetic and photochemical data for atmospheric chemistry: Volume VI – heterogeneous reactions with liquid substrates

“…We therefore adopt the value from the Bongartz et al (1994) study performed at lower pressure than the others. The solubility of HNO 2 in water has been directly measured by Park and Lee (1988). Their data are also in line with the extrapolated solubility from those by Becker et al (1996), who measured the solubility as a function of sulphuric acid composition (0.3 wt % and above).…”

“…Bambauer et al (1994) report an experiment in a cloud chamber, in which the cloud droplet seeds were NaCl, which seemed to be inconsistent with the second-order reaction of NO 2 in water. This and other evidence for apparent first order uptake with surprisingly high uptake coefficient can be discussed as due to reactions with impurities Msibi et al, 1993;Mertes and Wahner, 1995) rather than being representative of bulk accommodation limitation. Yabushita et al (2009) suggest the formation of a surface complex with chloride ions to explain enhanced NO 2 hydrolysis in mM chloride solutions (see also data sheet VI.A2.4).…”

“…The disagreement with Cape et al (1993) is likely due to inhomogeneous distribution of NO 2 in their reactor, as cautioned by the authors. Due to strong coupling between the liquid phase rate constant and the solubility, we calculate an average value of H k 1/2 extracted from the , Lee and Schwartz (1981) and Park and Lee (1988) and use the solubility as recommended to arrive at the expression for the rate constant. Bambauer et al (1994) report an experiment in a cloud chamber, in which the cloud droplet seeds were NaCl, which seemed to be inconsistent with the second-order reaction of NO 2 in water.…”

“…Due to the low solubility of NO 2 , a strong aqueous phase scavenger is required to get into a bulk accommodation limited kinetic regime. While the CWFT study by Msibi et al (1993) was likely affected by evaporation, Lee and Tang (1988) show evidence for the transition from reaction limited to bulk accommodation limited kinetics. Sosedova et al (2009) used an aerosol flow tube approach, which is practically free of gas phase diffusion effects, to obtain a bulk accommodation coefficient of 0.02 for deliquesced sodium salts of hydrochinone and dihydroxybenzoate, which is used as a basis for the recommendation for α b .…”

“…Schütze and Herrmann (2002) also used several simplifications and suggest that their uptake coefficient represents a lower limit to the bulk accommodation coefficient. Also, the diffusion correction commonly applied for high uptake coefficients to the droplet train experiments as reported by Van Doren et al (1990) has recently been challenged (Morita et al, 2003;Hanson et al, 2004;Garrett et al, 2006;. Van Doren's experiments at high temperature were measured at higher total pressure than those at lower temperature.…”