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www.atmos-chem-phys-discuss.net/8/17237/2008/
doi:10.5194/acpd-8-17237-2008
© Author(s) 2008. This work is distributed
under the Creative Commons Attribution 3.0 License.
The Cloud Condensation Nuclei (CCN) properties of 2-methyltetrols and C3–C6 polyols from osmolality and surface tension measurements
1Department of Meteorology, Stockholm Univ., Stockholm, Sweden
2Department of Applied Environmental Science (ITM), Stockholm University, Stockholm, Sweden
*now at: Department of Applied Environmental Science (ITM), Stockholm University, Stockholm, Sweden
Abstract. A significant fraction of the organic material in aerosols is made of highly soluble compounds such as sugars (mono- and polysaccharides) and polyols, including the 2-methyltetrols, methylerythritol and methyltreitol. The high solubility of these compounds has brought the question of their potentially high CCN efficiency. For the 2-methyltetrols, this would have important implications for cloud formation at global scale because they are thought to be produced by the atmospheric oxidation of isoprene. To investigate this question, the complete Köhler curves for C3–C6 polyols and the 2-methyltetrols have been determined experimentally from osmolality and surface tension measurements. Contrary to what expected, none of these compounds displayed a critical supersaturation lower than those of inorganic salts or organic acids. Their Raoult terms show that this limited CCN efficiency is due to their absence of dissociation in water, this in spite of slight surface-tension effects for the 2-methyltetrols. Thus, compounds such as sugars and polyols would not contribute more to cloud formation in the atmosphere than any other organic compounds studied so far. In particular, the presence of 2-methyltetrols in aerosols would not particularly enhance cloud formation in the atmosphere, contrary to what has been suggested.
Discussion Paper (PDF, 452 KB) Interactive Discussion (Closed, 3 Comments) Final Revised Paper (ACP)
Notice on Discussion StatusCitation: Ekström, S., Nozière, B., and Hansson, H.-C.: The Cloud Condensation Nuclei (CCN) properties of 2-methyltetrols and C3–C6 polyols from osmolality and surface tension measurements, Atmos. Chem. Phys. Discuss., 8, 17237-17256, doi:10.5194/acpd-8-17237-2008, 2008. Bibtex EndNote Reference Manager XML
