WMO/IGAC Impacts of Megacities on Air Pollution and Climate, 2008 - 2013

As of 2008, for the first time, the majority of the world’s population was living in urban areas, many in megacities (with populations over 10 million). Megacities are not only the center of growing economies, but are also large sources of air pollutants and climate-forcing agents. Under this initiative an assessment was written that for the first time summarized the current knowledge around atmospheric chemistry in megacities in Africa, Asia, South America, North America, and Europe. The assessment also summarized past and current research projects on this topic such as MEGAPOLI, CityZen, ICARTT, CalNex, MILAGRO, CareBeijing, PRIDE-PRD, and IMPACT. Finally the report identified knowledge gaps on atmospheric chemistry in megacities. The assessment was jointly sponsored by WMO.