Histories of monomers starting out in the midplane at ﹩r=5\;\mathrm{au}﹩ in a disk with ﹩\alpha ={10}^{-3}﹩ for three different dust-to-gas ratios. The dust population has the shape of the one in Figure 2, but the total dust mass is varied. After they are released at the location of the ﹩\bullet ﹩-symbol, particles can diffuse and settle vertically. They are incorporated in different aggregates as the result of collisions.