Mexico City’s air pollution is among the worst in the world. Exposure to
ozone and particulate matter created by traffic has been linked to premature
death, infant mortality, respiratory and cardiac disease, and cancer.
In Mexico City, air pollution is associated with approximately 4,000 premature deaths and 2.5 million lost work days annually. Diesel trucks and buses are a major part of the problem.They generate 70% of particulate air pollution in the metro area, although they represent only 4% of all vehicles. Sixty percent of these vehicles are 10 years old or older, lack emissions control systems and receive little to no maintenance. Retrofitting these buses to run cleaner is one key component of EMBARQ’s sustainable transportation strategy for Mexico City, a component with applications in many other cities around the world.

In 2004, EMBARQ and the U.S. Environmental Protection Agency (EPA) sponsored a pilot project to test how emissions control devices would perform under the high-altitude, stop-and-go conditions of Mexico City driving. EMBARQ’s Mexico City partner, the Center for Sustainable Transport (CTS), was selected by EPA to perform the tests. Using EPA-certified diesel particulate filters (DPF) or diesel oxidation catalysts (DOC) together with ultra-low-sulfur diesel fuel (ULSD), the retrofit team demonstrated the potential to eliminate up to 90% of the particulate emissions from new diesel buses and up to 20% from old diesel buses.