Ancillary benefits for climate change mitigation and air pollution control in the world's motor vehicle fleets
The global motor vehicle population has grown very rapidly in the past half century and is expected to continue to grow rapidly for the next several decades, especially in developing countries. As a result, vehicles are a major source of urban air pollution in many cities and are the fastest-growing source of greenhouse emissions. Strategies exist to reduce both problems, but many countries emphasize one over the other rather than pursuing strategies that reduce both concerns.