Spatiotemporal Dynamics of Urban Air Pollution in Dhaka City (2020–2024) Using Time-Series Sentinel-5P Satellite Images and Google Earth Engine (GEE)
2025
Md. Mostafizur Rahman | Md. Kamruzzaman | Mst Ilme Faridatul | György Szabó
This study investigated the spatiotemporal dynamics of four major air pollutants&mdash:carbon monoxide (CO), nitrogen dioxide (NO2), sulphur dioxide (SO2), and ozone (O3)&mdash:across Dhaka from 2020 to 2024 using Sentinel-5P TROPOMI satellite data. A 60-month time-series analysis was conducted, integrating spatial mapping, seasonal composites, and Mann&ndash:Kendall trend testing. Results indicated clear seasonal variations: CO and NO2 concentrations peaked during winter, with maximum monthly averages of 0.05287 mol/m2 and 0.00035 mol/m2, respectively, while SO2 reached a high of 0.00043 mol/m2 in pre-monsoon months. In contrast, O3 peaked in May (0.13023 mol/m2), following an inverse seasonal trend driven by photochemical activity. Spatial analysis revealed persistent pollution hotspots in central-western zones like Tejgaon and Mirpur for CO and NO2, while SO2 was concentrated in southern industrial zones such as Keraniganj and Jatrabari. The Mann&ndash:Kendall test identified moderate to strong increasing trends for CO (&tau: = 0.8, p = 0.086 in June and September) and SO2 (&tau: = 0.8, p = 0.086 in April and May), although most trends lacked statistical significance due to the limited temporal window. This study demonstrates the viability of combining satellite remote sensing and cloud-based processing for urban air quality monitoring and provides actionable insights for targeted seasonal interventions and evidence-based policymaking in Dhaka&rsquo:s evolving urban context.
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