1 Exhaust Emission Effects of Fuel Sulfur and Oxygen on Gasoline Nonroad

There have been a number of gasoline specifications that have changed or have been considered for change in the past few years. The most prominent of these changes has been summer volatility restrictions, wintertime oxygenated fuel requirements, and reformulated gasoline requirements which incorporate year-round oxygenate requirements and summertime emission requirements. For reasons described below, the effect of these fuel changes on nonroad gasoline engines’ exhaust emissions of carbon monoxide (CO), nitrogen oxides (NOx), and volatile organic compounds (VOC) is ascribed mainly to the oxygen content. Any expected changes to the fuel sulfur is expected to reduce SOx emissions only.