Spatial analysis of factors affecting air pollution in Tabriz city

In recent decades, Tabriz metropolis as the largest city in the northwest of the country has faced with increasing population growth and development of industrial, commercial, services and residential structures. Increasing development along with failure to comply with land use planning criteria has led to an increase in air pollution. Current study has been carried out in order to understand factors causing pollution in Tabriz city. Research method is descriptive analytical and the type of the information is documental- library. Eight indicators, i.e. floor area ratio, population density, intersection density, bus stop density, industries density, green spaces density, distance from industries and elevation were used as predictor variable. NO2 concentration was used as dependent variable and wind flow was used as an emission factor. In order to analyze the data, ordinary least squares and geographically weighted regression was used. According to the results of ordinary least square, the relationship between predictor variables and dependent variable is significant. So that the concentration of nitrogen dioxide increases with increase in floor area ratio, population density, intersection density, bus stop density, and industries density. In fact, there is a direct correlation between these variables and the concentration of nitrogen dioxide. By increasing the elevation and the distance from industries, the concentration of this pollutant decreases, which indicates an inverse correlation between these two variables and the dependent variable. Based on the results of geographically weighted regression model, considered variables account for 62% of air pollution in the city. Finally, maps of spatial variations of independent variables were drawn by using geographic weighted regression in the city of Tabriz.