Aldehydes and ketones are toxic compounds that present a high risk of producing cancer in humans and a high potential for the formation of tropospheric ozone. These compounds are emitted by the exhaust gases of internal combustion engines, due to incomplete combustion of hydrocarbons. The amount emitted by a vehicle in its daily urban traffic depends strongly on the engine technology (injection, valves, etc.), its electronic management and calibration, and its emission control systems (catalysts, EGR, etc.) as well as the type of fuel used (naphtha, diesel, biodiesel, ethanol, CNG, etc.). The results made it possible to analyse the behaviour in aldehyde and ketone emissions in the face of the higher oxygen content of the fuel and to verify that the model configuration evaluated complied with the various international reference standards.