Nowadays the increase of population and developmental programs in the world have resulted in increasing extension of urbanization regardless of environment considerations and the change of environmental factors has paved the way for many crisis like air pollution and climate changes. The consequences of such problems are usually affected by the human interference and hidden and obvious reactions of various environmental parameters which causes pollution.

The influence of pollution, has had unpleasant effects on varieties, population and all kinds of communities and in spite of the lack of emission pollution in the basis of the production, after the emission and the increased distance from the place of appearance has affected many large regions and increases the extension of many polluted places.

The emissions will risk the existence of all biological communities extensively and will finally accompany environmental destruction and decay and after covering largely, causes transboundary pollution and then great global changes and this process makes great ecological changes in the environment and finally causes unreversionable, complicated and valuable ecosystems which develop through prolonged years and use of simple actions and the apply of modern technology to improve and balance them is impossible.

At present, air pollution in large cities is one of the environmental problems of the country.

The population of the country is one of the important factors affecting the air pollution that much concentration of it and employment in one point, can result in complete destruction of environmental values and also the increase of population and economic development, cause the increase of fuel per capita.

The statistics and figures have demonstrated that with regard to the extension and population of the cities, motor vehicles, factories, industrial workshops and heating commercial instruments are the most pollutants of the country.

The importance of motor vehicles (%65) especially in large cities in polluting the air of country in comparison with other air pollutant resources is more.

Nowadays the cities of the country has complicated transport system, which this large cycle of traffic has been made because of development vehicles and transport of a large number of passengers intracity and consequently traffic cycle and the existence of critical points in traffic routes forms the most important source of air pollution in the cities and emissions from motor vehicles like CO, HC, NOx, S, SPM, Pb have important role in polluting the air of the cities.

Industries and factories are as progressive wheels of developmental programs and the basis of community economics and is necessary to improve the economic of the country and the continuity of such economic development needs a moving force which is natural in the form of using different sources and performance industrial plans without using these sources is impossible.

No doubt, every industrial activity in spite of the preparation of enough possibilities to make quantitative improvement and progress of life in the country has unfortunately had consequences.

For instance, the change of environmental natural balance and its destruction, decrease of usable source and the discharge of pollutants into the air and so industries often cause the most important factor of air pollution in the suburb of the cities and rural regions. The most important pollution caused by industrial activities based on the production process of cement, brick, metal melting, chemical industries, refineries, petrochemistries and power stations.

The concentration of the most pollutant industries in different cities on one hand and the development of traffic vehicles in each of the cities on the other hand have caused air pollution in the country. Besides, transport and industrial activities have been effective in producing greenhouse gases like CO₂ and methane.

The consumption of present common fossil fuels in transportation, industries, residential commercial heating resources have made the concentration of dangerous pollutants like Hydro carbons, nitrogen oxides, monoxide carbon and SPM.

Because a large portion of air pollutants production in the country relates to the transport therefore. The substitution and consumption of clean fuels is very important in the country.

The atmospheric and climatic conditions of cities from the geographical point of view are other factors that are mostly resulted in the severity of pollution in the cities.

The meteorological and climatic condition such as the existence of high and low pressure nucleuses and warm and cold fronts and etc in different areas of the country have important role in emission of pollution.

The formation of air stable layers next to the earth and also the formation of reflected heating layers in the neighborhood of that and thus inversion phenomenon which usually happens in cities in most months of the year, especially in winter, can prevent from vertical emission of pollutants in polluted areas.

The lack of wind in some of the areas, causes gradual transfer and vertical and horizontal emission of pollution. Such existed cases throughout the country together with geographic factors, topography of region like being valley, causes the severe air pollution.

Trees and urban green space which are among the social substructure have important function in decreasing air pollution. Since the effect of green space in decreasing of the air pollution is based on their density, therefore one of the factors of prevention from severe pollution in the air of the cities, is development of the urban green space which is considered less.

The cities of the country with historical and valuable buildings have special importance globally which are to be protected in particular these monuments have important share in attracting tourists and progress of country tourism industry. In this case, the adverse effects of caused by air pollution in historical buildings and cultural heritage are completely apparent and significant. Let’s add that yearly almost 300- 400 thousand ton gas and pollutants enter the atmosphere of the country because of the activity of energy producing units.

According to authentic report from 1980-1985, Tehran as the chiefest city of IRAN has had the third place from the point of pollution among 54 cities of the sake of world and at present for the sake of the increase of air pollutants and owing to U.N. Report is the first one.

The problem of air pollution in Mashad, Esfahan, Shiraz, Tabriz and Arak is severe and more important after Tehran. In 1992 Tehran has been first from the point of smoke, SPM in the air and has been second from the point of So₂.

The noticeable effects of air pollution are mostly in the form of vomiting, headache, severe heart- pulmonary diseases, instigation of eyes, allergy, metabolism disorder, breath shortage and asthma, increase of death (in the old ages) is considerably observable.

Therefore, as the environmental protection and development in the country are necessary, to achieve sustainable development, protection and preservation from environment should be considered among development programs.