Binary H₂SO₄‐H₂O homogeneous nucleation based on kinetic quasi‐unary nucleation model: Look‐up tables

Abstract

[1] Recently, we have shown that the binary homogeneous nucleation (BHN) of H 2 SO 4 and H 2 O can be treated as a quasi-unary nucleation (QUN) of H 2 SO 4 in the equilibrium with H 2 O vapor and have developed a kinetic H 2 SO 4 -H 2 O nucleation model, which simulates the dynamic evolutions of cluster distributions explicitly. In this paper we present improved and updated version of the QUN model, which has been modified through the incorporation of more rigorous thermodynamics of the cluster formation and the effect of the surface area of preexisting particles on nucleation rates. The difference in the model predictions of the improved and original QUN models is not dramatic; however, the improved QUN model is more consistent thermodynamically. The predicted BHN rates based on the QUN model are in good agreement with existing observations within the range of uncertainties. We also study the dependence of kinetic BHN rates on key input parameters and discuss the conditions in which the H 2 SO 4 -H 2 O homogeneous nucleation in the atmosphere may become significant. The nucleation rates look-up tables derived from the QUN model, which can be readily used to find the nucleation rates at given conditions, are presented. The look-up tables cover a wide range of key parameters that can be found in the ambient atmosphere, in the laboratory studies, and in the exhaust plumes. These look-up tables can be easily incorporated in multidimensional models to predict BHN rates, and they can be utilized directly for the analysis and interpretation of the observed nucleation events.

Laboratory studies of H<sub>2</sub>SO<sub>4</sub>/H<sub>2</sub>O binary homogeneous nucleation from the SO<sub>2</sub>+OH reaction: evaluation of the experimental setup and preliminary results

“…In comparison, predictions from classical nucleation theory showed that the initial [H 2 SO 4 ] has to be at least 10 10 cm −3 to observe significant binary J at RH<20% and 298 K (Vehkamäki et al, 2002). A recent kinetic quasi-unary nucleation model for H 2 SO 4 /H 2 O also showed that the initial [H 2 SO 4 ] has to be at least 10 11 cm −3 to observe significant binary J at RH<20% and 300 K (Yu, 2006). We estimated n H 2 SO 4 from 3-8 under our experimental conditions (Fig.…”

“…The most common feature of the new particle formation events is a substantial increase of number concentrations of nucleation mode particles (diameter <20 nm), reaching up to 10 5 -10 6 cm −3 in the condensable vapor-laden air. The involvement of sulphuric acid (H 2 SO 4 ) in nucleation has been widely suggested, with the binary Yu, 2006), ternary (Korhonen et al, 1999;, or ion-induced nucleation (Yu et al, 1998;Lee et al, 2003;Lovejoy et al, 2004). However, it was often found Ran set up for 15 min; but for J calculations, initial N were corrected with a factor of 5 to convert them to the steady state concentrations that the nucleation rate (J ) predicted from nucleation theories cannot explain the atmospheric observations (e.g., Weber et al, 1996).…”

Parametric studies of contrail ice particle formation in jet regime using microphysical parcel modeling

“…Homogeneous nucleation of new particles is described by the kinetic quasi-unary nucleation (KQUN) theory developed by Yu (2005Yu ( , 2006aYu ( , 2007. In the cases where the role of chemiions may be important, the kinetic ion-mediated nucleation (IMN) model developed by Yu (2006b) is used.…”

Laboratory and modeling studies on the effects of water and soot emissions and ambient conditions on the properties of contrail ice particles in the jet regime

“…The calculated exhaust plume's centerline temperature, velocity, and dilution ratio as a function of downstream distance were found to be consistent with experimental data collected in the chamber (Tacina and Heath, 2010). The contribution of microphysical processes is further divided into contributions of (1) homogeneous nucleation of new liquid particles, (2) coagulation between liquid particles, (3) activation of hydrophobic soot surfaces, (4) condensational growth of water vapor on soot particles, and (5) heterogeneous freezing of liquid coated soot particles: In our model, homogeneous nucleation of new liquid particles is described by the kinetic quasi-unary nucleation theory developed by Yu (2005Yu ( , 2006Yu ( , 2007. Coagulation of different liquid particles is described using Brownian coagulation kernels (Fuchs, 1989).…”