The operating performance of plant for removal of particulates from gases can be positively influenced by crude gas conditioning and other additive measures. These processes involve introduction of additional material or additional energy into the plant. Set goals are the reduction of particle emissions, reduction of operating costs, adaptation to new boundary conditions, or the opening up of new applications for the separators concerned. In the third of three surveys, conditioning by dosage of solids, liquids, or gases is considered. Precoating, heterogeneous condensation, particle formation by gas phase reaction, and other fundamental aspects are of relevance in this context. The possibilities and effects of additive dosage in the Eases of wet separators, electrostatic separators, and filtering separators are presented, discussed, and - wherever possible - assessed with regard to practical relevance.