Impact of engine technology on the vehicular emissions in Mexico City

The metropolitan area of Mexico City is the urban area of the country that presents the mast critical environmental problem due to fuel consumption. A ttempting to reduce the ambient concentration of pollutants, the environmen tal program adopted consisted of a broad series of strategies designed to i mprove the air quality. Modification of fuel formulation, which include com position and physical properties, provide a particularly effective way to r educe emissions. The reformulated gasoline in Mexico has reduced aromatics, olefins, and benzene contents as well as a lower Reid Vapor pressure. The regulated emissions (carbon monoxide, total hydrocarbons, and nitrogen oxid es) were evaluated for each vehicle as well as the speciated hydrocarbons p resent in the exhaust emission. With these data, we estimated the ozone-for ming potential of the fuels and correlate the results with the technology o f the vehicles. When these data are compared with those obtained in United States, there is an important difference in the technological devices relat ed to emission control in vehicles of the Mexican market. Moreover, our res ults strongly suggest that emission standards for new vehicles said in Mexi co must be tighten further in order equal those demanded in other countries .