A system and method for decontamination of chemical and biological agents over terrain in an outdoor environment is provided that utilizes ultraviolet radiation to break up hydrogen peroxide into radical species that interact with chemical and biological agents to render them harmless. In a preferred embodiment, peroxide is dispersed in a contaminated area and the peroxide is then exposed to ultraviolet radiation that causes the peroxide to dissociate into radical species. The interaction of the radical species formed by the peroxide dissociation with the chemical and biological agents renders them useless.