Whether ethanol gasoline is more environmental-friendly than pure gasoline in air pollutants’ emissions has been an important but controversial topic for over a decade. To investigate the question, we use quasi-experiment methods to analyze the changes in types of air pollutants’ concentrations near the race tracks taken by the NASCAR fuel-switching policy, which shifted from pure gasoline to an E15 blend implemented in 2011. We find that switching fuel to have 1 million racing miles in one race day can reduce up to 12.4% of ambient NO2 concentrations within areas 50 miles around the race tracks. Our research also suggests that before 2011 in the areas around the race tracks, especially in the Northeast states of the U.S., there might exist a relative deficiency of volatile organic compounds (VOC), which impeded and even reduced the accumulation of ground ozone, when more man-made NO? was produced during racing days.