Agglomerate Fractal Dimension Effects on Transport. ISDD calculated rate of transport over a 24 hour in vitro exposure fto Fe2O3 agglomerates with, a primary particle size of 34.6 nm, and a fractal dimension of 2.2 (A) or 2.4 (B). The media height was 3.1 mm. Each line represents a different number of particles per agglomerate. Increasing the size and mass of agglomerates decreases diffusion rates, but may not increase sedimentation rates. For more efficiently packed agglomerates (DF = 2.4, bottom panel), but not less efficiently packed agglomerates, increases in agglomeration size can increase the rate and extent of sedimentation.