monthly zoning of the air pollution and surveying its relationship with climatic factors (case study: mashhad city)

urbanization expanse and population growth, as well as pilgrim's possibility of some cities provide overuse of vehicles and consequently increased air pollution. thus by considering the importance of the impact of air pollution on human health, in this study, air pollution in terms of pm10 using psi standard index and inverse distance weighting is zoned in mashhad. on the other hand, meteorological parameters such as wind speed, wind direction and rainfall have also been analyzed, by comparing and overlapping in geographic information system and also by evaluation the relationship between climatic factors and psi index using pearson’s correlation coefficient, the impact of climatic factors on air pollution reduction is partially visible. so that in end of march and early of april has reduced the amount of air pollution due to spring rainfall and in the months of january and february, air pollution levels have risen than warm months due to less precipitation and temperature inversion. in addition, the wind direction had the greatest impact on reducing of air pollution and in the end of march and early of april and december, appear the highest correlation between them (r = - 0.902, p = 0.014, r = -0.817, p = 0.04 respectively). the most of air pollution have been seen in the city center around sadaf, lashgar and nakhrisi stations in majority of months, having more traffic, as well as less rainfall and wind speed and favorable wind direction.