Journal of Rescue Relief

en Integrated Hazard Analysis of Spatial Distribution of Air Pollution Indices in Tehran County Integrated Hazard Analysis of Spatial Distribution of Air Pollution Indices in Tehran County سوانح زیست محیطی Environmental disasters پژوهشي Research article <div dir="ltr" style="text-align: justify;">INTRODUCTION: Urban air pollution, especially in densely populated metropolises such as Tehran, has become one of the most serious environmental and health challenges. NO2, as one of the most important pollutants resulting from human activities, accumulates persistently in the surface layers of the atmosphere, especially in the cold seasons and under temperature inversion conditions. This study aims to analyze the combined risk of spatial and temporal distribution of NO2 in the cold seasons in Tehran city over a 7-year period (2018–2024) and to investigate the interaction between human and natural factors in the formation of this risk. METHODS: In this descriptive-analytical study with an integrated approach, daily NO2 concentration data were extracted from Sentinel-5P satellite images (TROPOMI sensor) in Tehran during the winter season from 2018 to 2024 (equivalent to 1397–1403 solar year). Using spatial extraction tools in the GIS environment, data were processed, seasonal averages were calculated, and raster-to-vector conversion was performed, and spatial and temporal distribution patterns of NO2 were plotted and analyzed.</div> <div dir="ltr" style="text-align: justify;">FINDINGS: The findings showed that the distribution pattern of NO2 has undergone significant spatial and temporal changes over the seven years, with the highest concentrations observed in central Tehran and northeastern regions in 2018 and 2019. In 2020 and 2021, coinciding with the restrictions imposed during the COVID-19 era, a significant decrease in pollution levels was observed, but since 2022, NO2 concentrations have increased again, and in 2024, a significant increase was observed in the southern and eastern regions. These changes indicate a shift in pollution centers from the city center to the suburbs and a return to a centralized pattern, which indicates extensive urban development and increased human activities in peripheral areas.</div> <div dir="ltr" style="text-align: justify;">CONCLUSION: According to the research results, NO2 pollution in Tehran is the consequence of a complex interaction between human factors (such as traffic, industry, and urban development) and natural conditions (temperature inversion and topography), therefore, it is considered a "combined hazard". Changes in spatial patterns of NO2 are a reflection of urban physical-functional developments and management policies</div> <div style="text-align: justify;">INTRODUCTION: Urban air pollution, especially in densely populated metropolises such as Tehran, has become one of the most serious environmental and health challenges. Nitrogen dioxide (NO₂), as one of the most important pollutants resulting from human activities, accumulates persistently in the surface layers of the atmosphere, especially in the cold seasons and under temperature inversion conditions. This study conducts an integrated hazard analysis of the spatiotemporal distribution of NO₂ in Tehran County over a seven-year period (2018–2024), with a focus on the interplay between anthropogenic and natural factors in shaping this hazard. METHODS: In this descriptive-analytical study with an integrated approach, daily NO2 concentration data were extracted from Sentinel-5P satellite images (TROPOMI sensor) during the winter seasons from 2018 to 2024 in Tehran. Using spatial extraction tools in the GIS environment, data were processed, seasonal averages were calculated, and raster-to-vector conversion was performed, and spatiotemporal distribution patterns of NO2 were plotted and analyzed. FINDINGS: The findings showed that the distribution pattern of NO2 has undergone significant spatial and temporal changes over the seven years. In 2018 and 2019, the highest concentrations were observed in central Tehran and the northeastern districts. A marked decline occurred in 2020 and 2021, coinciding with mobility restrictions imposed during the COVID-19 pandemic. However, from 2022 onward, NO₂ levels began to rise again, with a notable increase in southern and eastern areas by 2024. These shifts reflect a transition in pollution hotspots—from the city center toward peripheral zones—followed by a partial return to a more centralized pattern, indicative of extensive urban expansion and intensified human activities in suburban areas. CONCLUSION: According to the research results, NO₂ pollution in Tehran constitutes a “compound hazard,” resulting from the complex interaction of anthropogenic drivers (e.g., traffic, industry, and urban development) and natural conditions (e.g., temperature inversions and topography). The observed changes in NO₂ spatial patterns mirror transformations in urban morphology, land use, and environmental management policies. </div> Nitrogen dioxide, air pollution, Tehran, Sentinel 5 Nitrogen dioxide, Air pollution, Tehran, Sentinel 5P 202 212 http://jorar.ir/browse.php?a_code=A-10-1491-3&slc_lang=en&sid=1 Ali Asghar Abdollahi علی اصغر عبدالهی 100319475328460014675 100319475328460014675 No Geography, Faculty of Literature and Humanities, Shahid Bahonar University of Kerman, Kerman, Iran Sadegh Karimi صادق کریمی 100319475328460014676 100319475328460014676 Yes Faculty of Humanities, Department of Geography, Shahid Bahonar University of Kerman, Kerman, Iran دانشکده ادبیات و علوم انسانی، دانشگاه شهید باهنر کرمان،کرمان، ایران Naser Bay ناصر بای 100319475328460014677 100319475328460014677 No Geography, Faculty of Literature and Humanities, Shahid Bahonar University of Kerman, Kerman, Iran Masoud Ahmadi مسعود احمدی 100319475328460014678 100319475328460014678 No Environmental Engineering, Islamic Azad University, Science and Research Branch, Tehran, Iran Nader Oveisi نادر اویسی 100319475328460014679 100319475328460014679 No Environmental Engineering, Islamic Azad University, Science and Research Branch, Tehran, Iran