Cleaner Buses for Mexico City, Mexico

Abstract

In the Mexico City, Mexico, metropolitan area (MCMA), particulate matter pollution is estimated to cause 4,000 excess deaths and the loss of 2.5 million days from work each year. Emissions from diesel-powered buses and trucks are a major source of this air pollution. This paper summarizes the results from a pilot project aimed at testing whether advanced pollution-reducing technologies for diesel trucks and buses currently in use in the United States and Europe will work on Mexican buses and under Mexico City operating conditions. Diesel engines are the workhorses of buses in MCMA and many other regions; operators, vehicle and engine makers, and fuel suppliers have waited for each other to offer improved technologies. In this pilot project, 20 working buses in the Red de Transporte de Pasajeros del Distrito Federal (the Mexico City Diesel Bus Company) fleet were retrofitted with emissions control equipment and fueled with ultra-low-sulfur diesel fuel (ULSD). Results from emissions testing demonstrate that catalyst-based, diesel particulate filters can reduce particulate matter mass emissions by almost 90%. The project demonstrates that it is possible to have extremely clean buses operating in Mexico City by using commercially available technology and ULSD fuel. Even under Mexico City operating conditions and at Mexico City's altitude of 2,240 m, the existing buses in commercial service can greatly reduce the emissions of the pollutants dangerous to human health.