With a population of more than eighteen million people, Mexico City is a major metropolitan area where the effects of urban development on air quality are of immediate concern. Air pollution exposures and effects on forests in the Mexico City Air Basin are in many respects similar to those reported in the Los Angeles, California Air Basin. Studies of air pollution impacts on forests in these two regions may serve as models for urban areas all over the world. Although scientists have studied air pollution and its effects on forests and vegetation in the Mexico City Air Basin for years, this book reviews and synthesizes this body of work for the first time. This synthesis is particularly valuable as air pollution increases at an alarming rate along with global urbanization. A thorough discussion of regional geology, climate and hydrology, historical natural resource utilization, and sociological factors provide the context for evaluating air pollution impacts on the highly valued forests surrounding this megacity. The environmental and ecological consequences of chronic exposure to biologically important pollutants are considered in various case studies. Finally, the editors discuss the state of air pollution research in the Mexico City Air Basin and the outlook for the health and sustainability of forests within the Basin.