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Mexico City is one of the world s largest metropolitan areas, containing nearly 20 million inhabitants within the Valle de Mexico (also referred to as the Mexico City basin). The Valle de Mexico occupies ~1,300 km2 at a nominal elevation of 2,240 m above mean sea level, and is bordered on the east and west by mountains that rise 1,000 m above the valley floor, with low points to the north and south. Although its elevation is high, Mexico City s location at 19 degrees north latitude provides it with a temperate climate throughout the year. The climate is generally dry, but thunderstorms are frequent and. | Air Pollution History Air Pollution Any atmospheric constituent present as a result of anthropogenic activity or natural processes that causes adverse effects to humans animals vegetation or materials. Before 1200 AD Air pollution results from wood burning tanning decaying trash smelting of ores. Greek Rome - 3rd Century BC Theophrastus Aristotle student smell of burning coal was disagreeable and troublesome . - Seneca 61 AD noted oppressive conditions of the Roman air. - Roman s invented beach house to escape. - Rome under strong T inversions called heavy heavens. - Roman first chimneys 7 to 8 m tall - Evidence of lead glassware pipes etc copper coins zinc smelting Early Smelting Emissions Mineral deposits typically as sulfides Cu2S PbS ZnS E.g. Smelting for lead smelting for other metals is the same Pulverize and heat 2PbS 3O2 - 2PbO 2SO2 Reduce further by heating with carbon PbO C - Pb CO Pollutants Produced CO SO2 Hong et al. Greenland ice evidence of hemispheric lead pollution two millennia ago by Greek and Roman Civilizations Science 265 1994. Renberg et al. Pre-industrial atmospheric lead contamination detected in Swedish lake sediments Nature 368 1994. 1200-1700 AD London Middle Ages main pollution is limestone kilns heated with oak to produce quicklime CaCO3 s - CaO CaO H2O - Ca OH 2 s cement - Pollutants organic gases nitric oxide carbon dioxide organic PM London wood shortages led to use of sea-coal high sulfur content for kilns various industry and heating etc - Pollutants SO2 CO CO2 NO soot and PM - 1285 a commission established to remedy severe pollution 1306 Edward I banned coal use in lime kilns ignored and not enforced -little effect Use of sea-coal increased in London with time - John Evelyn 1661 wrote Fumifugium or the Inconvieniencie of the Aer and the Smoake of London Dissipated London smoke caused fouling of churches palaces clothes furnishings paintings rain dew water and plants Blamed brewers diers limeburners salt and sope-boylers Can .
