Evaporation of sulfate aerosols at low relative humidity
oleh: G. Tsagkogeorgas, P. Roldin, P. Roldin, J. Duplissy, J. Duplissy, L. Rondo, J. Tröstl, J. G. Slowik, S. Ehrhart, S. Ehrhart, A. Franchin, A. Kürten, A. Amorim, F. Bianchi, J. Kirkby, J. Kirkby, T. Petäjä, U. Baltensperger, M. Boy, J. Curtius, R. C. Flagan, M. Kulmala, M. Kulmala, N. M. Donahue, F. Stratmann
| Format: | Article |
|---|---|
| Diterbitkan: | Copernicus Publications 2017-07-01 |
Deskripsi
Evaporation of sulfuric acid from particles can be important in the atmospheres of Earth and Venus. However, the equilibrium constant for the dissociation of H<sub>2</sub>SO<sub>4</sub> to bisulfate ions, which is the one of the fundamental parameters controlling the evaporation of sulfur particles, is not well constrained. In this study we explore the volatility of sulfate particles at very low relative humidity. We measured the evaporation of sulfur particles versus temperature and relative humidity in the CLOUD chamber at CERN. We modelled the observed sulfur particle shrinkage with the ADCHAM model. Based on our model results, we conclude that the sulfur particle shrinkage is mainly governed by H<sub>2</sub>SO<sub>4</sub> and potentially to some extent by SO<sub>3</sub> evaporation. We found that the equilibrium constants for the dissociation of H<sub>2</sub>SO<sub>4</sub> to HSO<sub>4</sub><sup>−</sup>(K<sub>H<sub>2</sub>SO<sub>4</sub></sub>) and the dehydration of H<sub>2</sub>SO<sub>4</sub> to SO<sub>3</sub> (<sup><i>x</i></sup><i>K</i><sub>SO<sub>3</sub></sub>) are <i>K</i><sub>H<sub>2</sub>SO<sub>4</sub></sub> = 2–4 × 10<sup>9</sup> mol kg<sup>−1</sup> and <sup><i>x</i></sup><i>K</i><sub>SO<sub>3</sub></sub> ≥ 1.4 × 10<sup>10</sup> at 288.8 ± 5 K.