Abstract: An apparatus improves the efficiency and emissions of a combustion process by producing sufficient amounts of ozone in the air flow to the combustion chamber to enable more complete and cleaner combustion of the fuel. A plurality of ozone elements for producing ozone are disposed within a housing that is placed in the air intake to a combustion chamber such as a diesel engine. The ozone elements are bonded together in a cross-shaped pattern inside the housing. The apparatus includes one or more vortex scrubbers or vanes in the housing to cause the air flow to have a vortex action to increase the amount of ozone that flows into the combustion chamber. The vortex scrubbers comprise multiple double fins that are attached inside the housing. The vortex scrubbers include holes and/or serrated edges to increase the disturbance of the air flow over the ozone elements to increase ozone production. The mass of the ozone elements have a preferred ratio.