The hygroscopicity of organic aerosol in the atmosphere can be represented by a semi-empirical single parameter, κ. In this work we test possibilities for developing quantitative structure-property relationship (QSPR) models for κ based on chemical similarity. Models were developed in two ways: by manually assessing the suitability of several plausible physico-chemical descriptors; and by systematically evaluating hundreds of constitutional (e.g. number of particular atoms, bond types, molecular weight,...), topological, electrostatic, geometrical and quantum-chemical descriptors with the QSPR modelling software CODESSA (COmprehensive DEscriptors for Structural and Statistical Analysis). A set of 74 compounds with measured κ values was taken from the literature and prediction capabilities of the developed models were evaluated by leave-one-out cross-validation procedure. A 5-parameter linear regression model obtained with CODESSA was found to be the most suitable. Among the five descriptors, the two providing the highest contributions to the total variance were found to be (i) the final heat of formation divided by the number of atoms (69 %) and (ii) the ratio of molecular weight and molecular volume (16 %), although other topological and electrostatic descriptors were also of non-negligible importance for prediction of κ. The squared correlation coefficient and the root mean square error of a leave-one-out cross-validation procedure were 0.80 and 0.037, respectively. The results show that quantitative structure-property relationship approaches are useful for modeling κ.

中文翻译：

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使用定量结构-性质关系模拟有机气溶胶的吸湿性参数 kappa

大气中有机气溶胶的吸湿性可以用一个半经验的单一参数κ来表示。在这项工作中，我们测试了基于化学相似性为 κ 开发定量结构 - 性质关系（QSPR）模型的可能性。模型以两种方式开发：通过手动评估几个合理的物理化学描述符的适用性；并通过使用 QSPR 建模软件 CODESSA（结构和统计分析综合描述符）系统地评估数百种结构（例如特定原子的数量、键类型、分子量等）、拓扑、静电、几何和量子化学描述符. 一组 74 种具有测量 κ 值的化合物取自文献，并通过留一法交叉验证程序评估开发模型的预测能力。发现使用 CODESSA 获得的 5 参数线性回归模型是最合适的。在五个描述符中，发现对总方差贡献最大的两个是 (i) 最终形成热除以原子数 (69%) 和 (ii) 分子量和分子体积的比率（ 16 %)，尽管其他拓扑和静电描述符对于 κ 的预测也具有不可忽视的重要性。留一法交叉验证程序的平方相关系数和均方根误差分别为 0.80 和 0.037。