Reactive oxygen species, which are responsible for the removal of SO2 and NOx, generated under vacuum ultraviolet (VUV) radiation in simulated flue gas (N-2/O-2/CO2/H2O (v/v) = 74%/8%/10%/8% without SO2 and NOx) were determined. Under typical experimental conditions, 26.5 mu mol ozone, 1.7 mu mol hydrogen peroxide, and 0.3 mu mol hydroxyl radical were detected. The effects of H2O and O-2 contents, gas flow rate, and lamp power on the generation of reactive oxygen species were investigated. Results show that H2O and O-2 contents as well as flow rate significantly affected O-3 and H2O2 production. High content of H2O resulted in a decrease in O-3 production but an increase in H2O2 production, whereas O-2 content demonstrated the opposite effects owing to its varying absorption across sections. O-3 and H2O2 production increased with increasing flow rate, while their concentrations changed slightly. High-power lamps had a negligible effect on O-3 and H2O2 production, but O-3 production decreased and H2O2 production increased under extremely low-power lamp radiation. In addition, the variations of the production of reactive oxygen species were also correlated with the oxidation processes of VUV-induced simultaneous desulfurization and denitrification. (C) 2013 Elsevier B.V. All rights reserved.