Top: volume-filling factor of the cool clumps (black) and temperature profiles (red) of the early-M-type RSG models A (solid) and B (dashed). Center: densities of selected species from the FASTCHEM simulation, for model A. Bottom: same as the center but for model B. The color code for the displayed species is given in the bottom right corner. Solid lines refer to neutral and dashed lines to singly ionized species. For the definition of models A and B, see Section 4 and Fig. 4.