| There present 6.25 billion populations on the globe including half citizens. The rapid growth of urban people, inadequate expansion of a major city, overdevelopment of industries and fast addition of vehicle all have lowered the air quality in most metropolises. More than 1.6 billion citizens with 280 million Chinese citizens have been inhaling the non-attainment air, so their health gets injured to some extent. If policies and countermeasures that control pollution were not able to be implemented efficiently, the number would go bigger with release of pollutants from industry, vehicle and household increasing and urban residents swelling. Though different are pollutant components and concentrations in addition to threat from air pollution to citizens among various countries, the some key aspects are terribly similar. Many thousands of automobiles are swarming a city everyday so to make narrow, seriously polluted air belts crisscross over a city. The pollutants have formed a hot spot at intersections, traffic lights and traffic jams. Power plants, refineries, chemical factories, metal manufacturers, garbage incineration and a variety of factories inlaying on a city or gathering in an industrial camp emit toxicants to pollute the local air; but taller stacks of many factories spout a plumes of pollutants into atmosphere, spreading all over the city. Despite each household being a tiny pollution source, smog and dust they all launch make urban residential districts full of poisonous mist. The earlier a municipal authority is aware of contamination endangering health of the citizen, the more opportunity it has to improve the urban air quality as soon and low in cost as possible. It should have priority to evaluate how much pollutants throughout the urban threaten the residents and the ambience. If the air quality doesn't attain compulsory and advisable standards based on the health, the municipal or central governments must establish a system to guide the action, which ensures that the urban air quality turns better up. Before adopting an expensive measure to abate emission, municipality requires to forecast the potential effect of alternative control policies and actions against the bad air quality. When a series of the down-cutting measures need selecting but their cost and complexity are quite different; this prediction shows extraordinaryimportance. A municipal authority should set up and run a management system of urban air quality. In the process to create the effectual management system, several factors will be not only considered quantitatively many problems but also comprehended deeply. At first, it is confirmed whether there is a trouble with air pollution or there will be one. This demands to monitor and simulate what is ambient level of pollutants in distinct time and place. Supposing air quality can't reach these standards, it is necessary to practice the short-term and long-term control policies. The urban air quality management system consists of air quality monitoring network, emission inventory, digital prediction model, air quality standard, public information issue, effectual policies and countermeasures, resources and rights to run them. Once own those ingredients, governments can choose a suitable model to estimate interaction between those control policies in order to avoid that implementation of a policy might offset benefits from another one. Actually, technology progress provides a kind of swift and convenient approach to reduce emission and improve air quality so that a technical scheme would be used to tackle a technical problem. In people's opinion, the release can be modified only utilizing these technologies while a process and an action to bring some pollutants out aren't essentially changed. Nevertheless, governments should, in correct perspective, perceive that technologies be able to help those problems solving but hardly able to solve them entirely. The limitation of technologies in some aspect makes the governments seek the methods of management...
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