Despite the small amount of condensate, in most cases soot particles restructured when relative humidity was increased above its baseline value of 5%, and the response depended significantly on the coating material (Fig. ). The largest shrinkage was observed for soot particles treated with triethylene glycol (TEG) and its monobutyl ether (TEGMBE). Such particles restructured continuously with an increase in humidity, reaching maximum compaction at 85% RH, as also confirmed by Scanning Electron Microscopy (SEM) (Fig. ). Soot particles treated with ammonium nitrate (AN) and sulfuric acid (SA) also evolved continuously with an increase in humidity, but showed a lower ultimate shrinkage at RH 85%. A typical SEM image of such particles is presented in Fig. . Notable is the absence of the deliquescence transition for AN, an effect previously reported for pure AN particles. On the contrary, soot particles treated with glutaric acid (GA) remained unchanged at RH below 70%, but showed a sharp shrinkage upon reaching the deliquescence point of GA, 83.5-85% RH. Bare soot particles and soot particles treated with TDA showed no additional shrinkage during humidification because fresh soot is highly hydrophobic and TDA is immiscible with water. The difference in the extent of restructuring between different chemicals can be related to the condensate amount, which can be predicted by a numerical model, as described in the following section. treated by different chemicals. TEGMBE is excluded in f due to lack of aqueous solution data. Initial mobility diameter of fractal soot particles is 240 nm, and the chemicals used are ammonium nitrate (AN), glutaric acid (GA), sulfuric acid (SA), tetradecane (TDE), triethylene glycol (TEG), and triethylene glycol monobutyl ether (TEGMBE). Gfd and several other parameters used to express changes in the particle size and morphology are defined in the Methods section.