Figures & data
Figure 1. Comparison of predicted vs. experimentally observed κorg. Petters et al. (Citation2016) (red circle) is based on a group contribution method (UNIFAC) that accounts for solution non-ideality. The entirely soluble case (blue triangle) assumes water-solubility, no dissociation (ν = 1), and ideal solution (Φ = 1) (Equation (Equation1[1] )). Density is estimated using Equation (Equation3
[3] ). The third case (yellow square) is based on estimated solubility (Equation (Equation10
[10] )) and surface activity where available (Section 2.4). The dotted lines correspond to two-fold differences. κ values less than 10−3 are shown as 10−3. Table S2 provides the individual compound names and corresponding values.
![Figure 1. Comparison of predicted vs. experimentally observed κorg. Petters et al. (Citation2016) (red circle) is based on a group contribution method (UNIFAC) that accounts for solution non-ideality. The entirely soluble case (blue triangle) assumes water-solubility, no dissociation (ν = 1), and ideal solution (Φ = 1) (Equation (Equation1[1] )). Density is estimated using Equation (Equation3[3] ). The third case (yellow square) is based on estimated solubility (Equation (Equation10[10] )) and surface activity where available (Section 2.4). The dotted lines correspond to two-fold differences. κ values less than 10−3 are shown as 10−3. Table S2 provides the individual compound names and corresponding values.](/cms/asset/a50048e8-dbef-4cbb-ab5c-68dd17f53e66/uast_a_1352082_f0001_oc.gif)
Figure 2. Simulation results of α-pinene SOA without inorganic seed. The 2D-VBS distribution is taken from Donahue et al. (Citation2012). Ddry = 100 nm. (a) Distribution of organic aerosol volume in terms of O/C and logC*. The solid lines correspond to intrinsic κ. The dotted lines correspond to volume-based solubility C. (b) Köhler curves considering only solubility (black) and entire non-aqueous, aqueous, and surface partitioning (full partition). (c) Assumed/estimated surface tension. Solubility only case assumes surface tension of water. Full partition case assumes Γimax' = 1.45 × 10−6 mol m−2 and K'i = 3.5 × 102. (d) Estimated non-aqueous, aqueous, and surface phase partitioning. (e) Estimated non-aqueous and aqueous phase partitioning.
Figure 3. Summary of surface activity parameters for various organic compounds. Table S4 provides individual compound names and corresponding values.
Figure 4. Predicted κ vs. O/C relationships for (a) no inorganic seed case and (b) 10% ammonium sulfate seed case. The solid line corresponds to the median values of 1000 Monte Carlo simulations. The dotted lines correspond to 25 and 75 percentile. The simulations are performed at 10, 100, and 1000 μg m−3 of reacted precursors: α-pinene (Donahue et al. Citation2012), ambient reactive organic gas (Murphy et al. Citation2012).
