An Evaluation of the LPG Vehicles Proqram in the Metropolitan Area of Mexico City

摘要

The environmental agency in the metropolitan area of Mexico City has launched a program to introduce more energy-efficient modes of transport, one of which is the use of alternative and less polluting fuels. With that per- spective in mind, a liquefied petroleum gas (LPG) fleet of vehicles is exempt of the mandatory `'one day without a car'' program if the emission of pollutants is below the standard authorized for that specific purpose. Today, about 28,000 light-duty vehicles and heavy-duty trucks circu- late in the area, most of them as aftermarket converted vehicles. In this work, we evaluated regulated exhaust emission and other parameters on 134 representative ve- hicles of that fleet. From the data obtained, an estimate of emission factors and their contribution to the global emission in the metropolitan area is provided. It is con- cluded that more than 95 of the in-use vehicles using LPG presented regulated emissions which exceeded in one or more the environmental regulations values required for certification. The poor maintenance of the vehicles and the type of conversion kit installed could be the cul- prits of the results obtained.