Figure 1. TEM images of Fumed Silica nanoparticles, (a) HSPI Lab-scale Sample of material collected inside the reactor, (b1 – b2) HSPI Pilot scale Samples collected from the Baghouse and (C1) Evonik commercial grades A90, (c2) Evonik commercial grade A150, and (c3) Evonik commercial grade A200 [2].