Temporal evolution of the dust surface density distribution per logarithmic bin of grain size σ(r, a) (see Eq. (C.1)), for Model IV. In each panel, the solid white line shows a Stokes number of unity (radial drift reaches its maximal efficiency), the dotted green line shows the drift limit (Eq. (19)), and the dashed cyan line shows the fragmentation limit (Eq. (20)). The horizontal solid dark gray lines show a grain size of 1 mm.