Effect of injection of di- and tricyclic aromatic compounds on post-combustion formation of polychlorinated dibenzo-p-dioxins and dibenzofurans

► Injection of dibenzofuran (DF) and fluorene reduced the Tri-PeCDD concentrations. ► Some of the reduced congeners were 2,3,7,8-substituted, i.e. TEF-congeners. ► TEQ values decreased by 68-23% during DF injection, with lowest reduction at 450 °C. ► A hypothetical pathway involves formation of radical species from fluorene and DF.