It is noteworthy for ethanol, acetaldehyde and ethylene
emissions, when ethanol blend fuel was combusted in motorcycle
engine. As is shown in Fig. 3, ethanol was not observed
in the exhaust emissions for base fuel. Acetaldehyde
emission increased slightly for the use of ethanol–gasoline
blended fuels, since it may be produced through the partial
oxidation of ethanol in E10 fuel. It is well known that humans
develop irritation of the eyes, skin and the respiratory tract,
when exposed to acetaldehyde vapors. Ethylene emission
amount was higher for E10 fuel than that for base fuel at