Abstract

Megacities are now a common phenomenon in many regions around the world and present major challenges for the global environment. The concentrations of people and their activities have resulted in higher demand for energy and consumption of fossil fuels, leading to air pollution that affects public health and visibility, causes regional haze and acid deposition, and alters the earth’s climate. Recent advances in real-time pollutant measurement technologies and improved air quality models are allowing scientists to better understand the emission sources of pollutants and the complex atmospheric processes leading to severe air pollution, and providing policy makers the tools for designing cost effective mitigation strategies. This study addresses the effects of megacities and urban complexes on the Earth’s atmosphere, using Mexico City and Santiago as examples of cities that have been actively managing their air quality. Both cities demonstrate the types of environmental problems experienced by many urban centers and confront similar challenges to solving them. With appropriate planning, dedicated scientific research, robust emissions control policies, and effective access to advanced technologies and financial support, these urban centers also have the opportunity to manage the growing population sustainably while reducing atmospheric pollution and its impacts.