Study & Assessment of the Effect of Climatic Element of Precipitation on the Degree of Pollution & Pollutants of Tehran Big City by the Use of Schefe Model and G.I.S Technique During the Two Past Decades

Civic areas are the major living field for the ever –increasing largest part of the world's population .population growth, development of city-settling and a change in the ways and attitudes of people's lives have created significant problems in big cities. Nowadays, big cities encounter such problems as air pollution, lack of sufficient green space, irregular increase of vehicles and population, etc. Tehran is considered as one of main demographic, political, economic, commercial and industrial regions in the country and occurrence of any climatic changes leads to irreparable losses such as shortage of water resources, severe floods, soil erosion, etc while this matter can be a factor to cause environmental problems systematically. Considering the fact that Tehran is Located in Alborz mountain foot and its many north –west to south-east Branches produces several effects on the city and because of its location in the mountain slope, its general level has a steady height above the sea level. Hence, its amount of rainfall undergoes severe changes. In fact, the amount received by the heights is rather much more than that of the lower points annually (Zargham, 1377, p.53). In this research, the trend of precipitation has been measured and examined by the use of data from 5 selected synoptic and 3 pluviometer stations of Tehran city during the statistical period of 20 years (1364-1384) and the degree of its correlation with the amount of pollutants in Tehran city has been measured using the data from Pollution polls stations which have been located according to synoptic stations, and SCHEFE and square Omega (w2) models.