The air pollution is the result of multiple factors: increased consumption of energy, development of mining, metallurgy and chemicals, traffic and air from the incineration of garbage, industrial waste, etc. Thus, production and energy use are the main engines.
Air pollution occurs mainly in urban and urbanizing areas of activities, not only because of the concentration of industries and households, but also because of the movement of motor vehicles. The sprawl of big cities is a corollary of transport needs ever more numerous.

There are also the tropical vegetation fires from slash and burn cultivation, which emit soot, carbon dioxide, carbon monoxide, hydrocarbons, carbon monoxide, nitrogen dioxide and nitrogen. This pollution is still one of the most important. It is very clearly visible on satellite imagery.

The pollution comes from various sources so that discharge pollutants called primary. Then, contact each other by chemical reactions and synergy with other components of the atmosphere, these precursors generate so-called secondary pollutants, even at high dilution, which are very toxic. “Thus, sulfur dioxide (SO2) is oxidized in air to SO3, which, in turn, will, with water vapor, sulfuric acid. It will thus crucially, with nitric acid formed from nitrogen oxides, the emergence of the phenomenon of acid rain, a real scourge in industrialized countries. ” ( Encyclopædia Universalis , 1998). (Encyclopaedia Britannica, 1998). This is an example that illustrates the complexity of the phenomenon and consequences of a single primary pollution. Under these conditions, the experts find it more difficult to characterize the upstream transmitters of pollution, which also slows decision making. In fact, risk prevention does not yet appear in our acquired companies rather react when sometimes tragic environmental event occurs, as evidenced by the recent environmental disasters.