It is known that introducing an electric field, magnetic field, radiation, etc. to the flame improves the combustion characteristics of engines and boilers; such as an increase in the size of the flame, a shortening of combustion period, a rise in combustion efficiency and a reduction of emissions. In this study, the researchers consider the results of previous experiments in which radiation and air negative ions are excited to measure the practical effects of these combustion phenomena toward the reduction of fuel consumption, emissions and environmental load. As a result, the authors have estimated that combustion is improved when a large amount of OH · CH radicals are generated in the field of combustion.