Assessing the Impact of Urbanization on Air Pollution and Land Surface Temperature Using Remote Sensing Data in Google Earth Engine: A Case Study of Tehran Province (2018–2022)

Abstract

This study examines the environmental impacts of urbanisation trends in Tehran Province, Iran, from 2018 to 2022, utilising Visible Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB) data as a proxy for human activities. Its effects on air pollution (nitrogen dioxide (NO₂), carbon monoxide (CO), and ozone (O₃) from Sentinel-5P and land surface temperature (LST) from Moderate Resolution Imaging Spectroradiometer (MODIS)) were analysed in Google Earth Engine (GEE). VIIRS DNB showed a sharp upward trend, indicating rapid urbanization. NO₂ pollution increased significantly across the region, while CO and O₃ exhibited weak decreasing and increasing trends, respectively. Daytime and nighttime LST rose by approximately 1°C overall, reflecting the urban heat island (UHI) effect despite fluctuations. Correlation analysis (r) revealed strong links between DNB and NO₂/CO (r=0.59–0.72) (a key contribution underscoring urbanisation's direct emission drivers), moderate with nighttime LST (r up to 0.38), and weak with O₃, underscoring urbanisation's role in driving pollution and heat. These findings emphasise the need for intensified emission controls, green infrastructure, and sustainable urban planning in rapidly growing cities like Tehran.