Resumo de Urban Air Pollution In Megacities Of The World

UrbanAir Pollution in Megacities of the World by Asim Khan The freshness of the air in one's environment has amost fundamental and direct impact on the quality and length of one's life. Imaginethis scene and you have in your mind the current state of affairs in MexicoCity, a City whose air was recently ranked by the World Health Organization(WHO) as the most contaminated in the world. In 1974 the Global Environment Monitoring System (GEMS) wascreated by the World Health Organization and The United Nations EnvironmentProgramme (UNEP) to monitor air pollution in large cities of the world. Of foremost concern in monitoring air quality in largecities is the health and well-being of urban residents. The concentration ofambient air pollutants in many of the cities are high enough to cause increasedmortality, disease prevalence, deficits in pulmonary function andcardiovascular and neurobehavioral effects. The most recent WHO/UNEP report on air quality in 1992focused on 20 of the 24 megacities of the world. The study of air pollutionproblems in the 20 megacities is intended to guide efforts to so lve andprevent some of these problems from occurring in emerging megacities. The first observation made by the report is that airpollution is widespread across the megacities and is often most severe incities in developing countries. The worst group of the megacities in terms ofair pollution consists of Beijing, Cairo, Jakarta, Los Angeles, Mexico City,Moscow and Sao Paulo. The suspended particulate concentration of the air has asignificant impact on one's health. These are the three most developedmegacities in the world. Bus drivers have the highest prevalence of chronicrespiratory problems in the Philippines in the Pacific Rim. For the cities surveyed, high levels of lead were recordedin the air of Cairo and Karachi and, to a lesser extent, in Bangkok, Jakarta,Manila and Mexico city. Lead is now banned in petrol in countries like the US,Japan, and Sweden. In most EU countries the permissible amount of lead inpetrol is highly limited. Motor vehicle traffic is a major source of air pollution inthe megacities. In half of them it is the single most important source. In theabsence of controls, the automotive emissions will likewise increase. Theexperience of the current megacities in the developed countries is now beingrepeated in the developing cou ntries. Pro motion of the use of mass transitand finding alternatives to open burning of refuse provide some otheropportunities for reducing air pollution in the near term In the longer term, preventivemeasures must be incorporated in new industrial and urban developments.

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