Dust-to-gas ratio normalized to the column density ratio (f) as a function of z, for both viscous (dashed line) and MRI-turbulent prescriptions (solid line) and for three values of the “settling parameter” S_z ≡ St/ ⟨ δ_z ⟩ _P, with ⟨ δ_z ⟩ _P = 10^-2. In the viscous prescription, this ratio falls off as a “double Gaussian” whereas it only does so as a Gaussian for the MHD prescription over the bulk of the disk thickness, before decreasing as a “double Gaussian” in the corona (here at | z |  > z_max = 3.0H).