A system and method for the decontamination of indoor air and surfaces having biological, chemical or physical contamination wherein the system is mounted on a wall or the like in the area to be treated. An ozone gas generator is positioned within the housing of the system for generating ozone gas in the housing. The housing also includes an exhaust fan assembly which exhausts the ozone gas and air mixture from the housing into the area to be treated. The system may be operated continuously or at predetermined times and for predetermined lengths of time.
