The process of production and later use of goods or the rendering of certain services is associated to the generation of wastes. When the rate of generation of these wastes is greater than the rate of purification of the system of which is part the productive process, it we say that this system is polluted (Zellner, 1995 ; Zellner et al., 1996).

The characteristics of air pollution in a given region are determined by (Faiz et al, 1990):
 

•  The type of pollutants emitted, their rate of emission and their magnitude, that are related to the sources of emission,    either mobile or not.
•  The topographical and meteorological conditions that affect the dispersion and concentration of the pollutants.
•  The set of production factors and the technology applied in the economical activity, and their impact on the types and levels of emission.
•  The range of the economical activity and the density of population exposed to pollutants.

The sources of atmospheric pollution are not uniformly distributed in the world, but mostly concentrated in the urban centers and industrial areas. Due to this, the pollutants do not mix easily with clean air, generally from rural areas, and they can remain for long periods of time in the atmosphere, near to their place of emission.

References

FAIZ, A.; SINHA, K.; WALSH, M.; VARMA, A.; 1990. Automotive Air Pollution: Issues  and Options for Devoloping Countries. Doc. de Trabajo 492 de los Funcionarios del PRE. Banco Mundial, Depto. de Infraestructura y Desarrollo Urbano; Washington, D.C., U.S.A.

ZELLNER, M; 1995. Identificación de Areas de Riesgo de Contaminación Atmosférica en la Ciudad de Buenos Aires. Seminario de Licenciatura, Universidad C.A.E.C.E., Buenos Aires.

ZELLNER, M; CAPURRO, A. F. ; JANKILEVICH, S. S. ; 1996. Identificación de Areas de Riesgo de Contaminación Atmosférica en la Ciudad de Buenos Aires. Serie Programa de Investigación y Desarrollo Ambiental Nº 10, Universidad de Belgrano, Buenos Aires.