Spatiotemporal Variations of Sulfur Dioxide Pollution and Identification of Critical Areas in Isfahan Province Using Satellite Data

This research analyzes the spatial-temporal concentration of sulfur dioxide in Isfahan province, emphasizing the role of major emission sources such as power plants and metal smelting industries, and aims to investigate changes and identify critical areas.In this research, sulfur dioxide column totals were extracted using data from the TROPOMI sensor on the Sentinel-5 satellite. Data processing was performed in the Google Earth Engine environment using the JavaScript programming language, and spatial analyses were conducted in the ArcGIS environment.Spatial analyses were conducted using ArcMap and the statistical method of Moran's I and hot spot analysis, including mapping of the six-year average and examination of annual, seasonal, and monthly trends.The results showed that sulfur dioxide in Isfahan province is clustered in two main hotspots, southwest of Isfahan and north of the province (Kashan), which are associated with the establishment of large industries and power plants, While the highlands and eastern parts of the province, with their low industrial density, have the lowest concentration.The average concentration of SO₂ varies from 0.0000338 to 0.00041 mol/m², with peak values in industrial areas reaching 0.00027 to 0.00041 mol/m².The annual trend indicates an increase in pollution from 2019 to 2021, followed by periodic fluctuations associated with atmospheric stability and industrial activity. Also, in cold seasons, especially winter, the concentration of sulfur dioxide increases dramatically due to temperature inversion and heavy fuel consumption.Analysis of the global Moran's I index confirmed a strong and clustered spatial correlation, indicating the effective role of stationary emission sources in pollutant dispersion.