A simple and efficient method for simultaneous desulfurization and denitrification via vacuum ultraviolet (VUV) irradiation and with no additional chemicals is presented. The simultaneous removal of 90% SO2 and 96% NO (NO + NO2) was achieved from the simulated flue gas under the irradiation from a low-pressure mercury lamp with main wavelengths of 185 and 254 nm, respectively. The composition, flow rate, and temperature of the simulated flue gas, as well as the VUV light intensity, were evaluated as the factors impacting on the efficiency of SO2 and NO removal. The center dot OH, center dot HO2, center dot O-2 and O-3 produced from the photolysis of H2O and O-2 were concluded as the major reactive oxygen species that oxidized SO2 and NOR. The additional center dot OH and center dot HO2 generated through the reactions of NO + center dot HO2 and SO2 + center dot OH\center dot HO2 improved treatment efficiency, while the oxidation products of NOR, e.g., NO2, HNO2, HNO3, and HNO4, consumed massive reactive oxygen species (such as center dot O, center dot OH, and center dot HO2) and thereby reducing the removal efficiencies. The main reaction products were characterized as H2SO4 and HNO3 by ion chromatography, which could be used as chemical or fertilizer raw materials. (c) 2014 Elsevier B.V. All rights reserved.