Air pollutant emission abatement using application of various ethanol-gasoline blends in high-mileage vehicles

The possibility of using ethanol-gasoline blends as fuel for vehicles as air quality management tools has been raised. In this study, two passenger cars with different accumulated mileage, i.e., low-mileage (35,000 km), and high-mileage (140,000 km) cars, were tested to investigate the ethanol-gasoline blend effect on emission abatement. Three ethanolgasoline blends, containing 3, 10, and 20% ethanol by volume in gasoline, and one unleaded gasoline, were used as test fuels. Criteria pollutants (CO, THC, and NOx), volatile organic compounds, and carbonyls were evaluated on a chassis dynamometer using the United States Federal Test Procedure. The exhausts of these criteria pollutants and BTEX (benzene, toluene, ethylbenzene, and xylenes) were lower while using ethanol-gasoline blends, even in the case of the high-mileage car fuelled with an E3 blend. However, formaldehyde and acetaldehyde emissions increased as the ethanol content in the gasoline was increased. The influence of ethanol blends on aldehyde emissions was more significant for the high-mileage car; there was an increase of 22-38% as compared to commercial gasoline. The results also showed that using ethanol-gasoline blends may lead to low ozone-forming potential (24-46%) as compared to using commercial gasoline. In terms of toxicity-based emissions, ethanol-gasoline blends ranked higher in cancer and acute-effects, especial for the high-mileage car. In brief, this study showed that ethanol-gasoline blends could be applied in in-use passenger cars without any engine adjustment in order to reduce the emission of criteria pollutants and the ozone-forming potential of VOCs as compared to using unleaded gasoline, but there may be an increase in some carcinogenic toxics emissions.