Each four polycyclic aromatic hydrocarbons (PAHs) was reacted with OH radical at $1.5{AA}$ distance by CAChe MOPAC 2000 program. These results were compared to those reported experimental results. Reaction positions of all four PAHs corresponded with predicted positions in which ${Delta}$E(HOMO-LUMO) was approximately 4.7. Finally oxygen of OH radical combined with PAH and quinone form of products were produced. These results indicate that the proposed determining the ${Delta}$E(HOMO-LUMO) can be effectively applied to predict reaction position of recalcitrant compounds such as dioxins, PCBs, POPs, and etc.