Abstract: A device for removal of SO.sub.2 and NO.sub.x from flue gas by high frequency discharge has a chamber having a first inlet opening for entry of flue gas into the chamber and an outlet opening for flue gas to exit from the chamber after removal of SO.sub.2 and NO.sub.x. A generator and electrode produce a high frequency electric field of sufficient strength in the chamber to produce high energy electrons that achieve both excitation and ionization potentials of N.sub.2, O.sub.2 and H.sub.2 O, whereby to produce free radicals of OH., O.sub.2 H., N., O. and H. which react with SO.sub.2 and NO.sub.x molecules in the flue gas. A second inlet opening into the chamber adds ammonia to the SO.sub.2 and NO.sub.x for reaction with the free radicals in neutralization producing ammonium salts from the SO.sub.2 and NO.sub.x in the flue gas exiting from the chamber.