Aspect ratio (left) and midplane temperature (right) as a function of orbital distance for the discs with the BOD, the MRN distribution and a disc that utilizes the Bell & Lin (1994) opacities. All of the simulations have α = 5 × 10⁻³, Σ_g,0 = 1000 g cm⁻², and f_DG = 1%. We also show the aspect ratio of the simulations with 1 and 100 μm for reference. The Bell & Lin (1994) opacities are based on micrometer-sized particles resulting in comparable aspect ratios. The main differences with the discs including the full grain size distributions are the steeper radial temperature (and thus aspect ratio) gradient for the disc with the Bell & Lin (1994) opacities and the reversed slope within 4 AU. These influence the migration speed and direction of planets embedded in those protoplanetary discs (see Figs. 13–15). The gray areas correspond to the water iceline transition.