Air Pollutants Exposure and Health Effects during the MILAGRO– MCMA2006 Campaign

Mexico City Metropolitan Area (MCMA) is one of the most densely populated cities in the world, with 18 million people according to the 2000 census (INEGI, 2001). MCMA is at an altitude of 2240 m above sea level, surrounded by mountains on the south, west, and east. Air pollution driven by local emissions can affect large areas within closed valleys, where restricted air movement concentrates the pollutants. Due to the altitude and latitude, MCMA receives intense solar radiation, a condition that added to a less efcient combustion promotes the photochemical formation of secondary pollutants such as ozone and particulate matter (PM) (Molina and Molina, 2002).