University of Sistan and Baluchestan Journal of Natural Environmental Hazards 2676-4377 Articles in Press 2025 11 04 Spatial Analysis of Air Quality and Environmental Pollutants in Tehran Metropolis Spatial Analysis of Air Quality and Environmental Pollutants in Tehran Metropolis 1 1 9515 10.22111/jneh.2025.52985.2135 FA Abazar Esmaeili Mahmoudabadi PhD student at climatology, Physical Geography Department, University of Tehran, Tehran, Iran Aliakbar Shamsipour Associate Professor, Physical Geography Department, University of Tehran, Tehran, Iran Hosein Mohammadi Professor, Physical Geography Department, University of Tehran, Tehran, Iran Journal Article 2025 08 18 The air quality in many Iranian metropolises, particularly those with high population density, is far from satisfactory. industries, and construction and commercial activities over the past few decades. In this study, both ground-based monitoring data and spatial layers were utilised. Data analysis revealed that the spatial distribution pattern of the Air Quality Index (AQI) is influenced by both human and natural factors, exhibiting a complex and multi-layered structure. Areas with high population density, proximity to main traffic corridors, and the presence of deteriorated urban fabrics experienced the highest pollutant concentrations, indicating a strong link between the urban form and the severity of air pollution. Furthermore the location of industrial and commercial land uses, along with high volumes of private vehicles and freight traffic, played a significant role in exacerbating pollution. Spatial analysis of pollutants showed that PM2.5 had the greatest impact on air quality, with concentrations exceeding standards in most monitoring stations, particularly in densely populated and deteriorated urban areas. PM10 exhibited a similar pattern but with a wider dispersion, reflecting the influence of both local sources and natural and anthropogenic dust activities. CO and NO₂ were mainly associated with traffic and vehicle density, showing the highest concentrations along main transportation routes and in densely populated areas. SO₂ was primarily concentrated in industrial zones and around fuel and energy facilities, highlighting the role of industrial activities and fossil fuel consumption in air pollution. The AQI indicated that most stations frequently experienced unhealthy periods for sensitive groups and occasionally unhealthy conditions for the general population. The spatial variations of the AQI were consistent with the spatial distribution of pollutants, with central and industrial areas facing the highest risks. These findings suggest that a combination of urban sources, traffic, and industrial activities contributes to the complex pattern of air pollution in Tehran. The air quality in many Iranian metropolises, particularly those with high population density, is far from satisfactory. industries, and construction and commercial activities over the past few decades. In this study, both ground-based monitoring data and spatial layers were utilised. Data analysis revealed that the spatial distribution pattern of the Air Quality Index (AQI) is influenced by both human and natural factors, exhibiting a complex and multi-layered structure. Areas with high population density, proximity to main traffic corridors, and the presence of deteriorated urban fabrics experienced the highest pollutant concentrations, indicating a strong link between the urban form and the severity of air pollution. Furthermore the location of industrial and commercial land uses, along with high volumes of private vehicles and freight traffic, played a significant role in exacerbating pollution. Spatial analysis of pollutants showed that PM2.5 had the greatest impact on air quality, with concentrations exceeding standards in most monitoring stations, particularly in densely populated and deteriorated urban areas. PM10 exhibited a similar pattern but with a wider dispersion, reflecting the influence of both local sources and natural and anthropogenic dust activities. CO and NO₂ were mainly associated with traffic and vehicle density, showing the highest concentrations along main transportation routes and in densely populated areas. SO₂ was primarily concentrated in industrial zones and around fuel and energy facilities, highlighting the role of industrial activities and fossil fuel consumption in air pollution. The AQI indicated that most stations frequently experienced unhealthy periods for sensitive groups and occasionally unhealthy conditions for the general population. The spatial variations of the AQI were consistent with the spatial distribution of pollutants, with central and industrial areas facing the highest risks. These findings suggest that a combination of urban sources, traffic, and industrial activities contributes to the complex pattern of air pollution in Tehran. https://jneh.usb.ac.ir/article_9515_0feaae480d2ed4eb4efbb4ea4111295f.pdf