Motor vehicle emission tests were performed on 12 in-use light duty vehicles, made up of the most representative emission control technologies in Mexico City: no catalyst, oxidative catalyst, and three way catalyst. Exhaust regulated (CO, NO{sub}x, and hydrocarbons) and toxic (benzene, formaldehyde, acetaldehyde, and 1,3-butadiene) emissions were evaluated for MTBE (5 vol )- and ethanol (3, 6, and 10 vol )-gasoline blends. The most significant overall emissions variations derived from the use of 6 vol ethanol (relative to a 5 MTBE base gasoline) were 16 decrease in CO, 28 reduction in formaldehyde, and 80 increase in acetaldehyde emissions. A 26 reduction in CO emissions from the oldest fleet (展开▼
