Abstract : Using high-resolution Sentinel-5P satellite data, this study investigates the relationship between the main sources of air pollution and the concentration of NO 2 gas in the tropospheric column during the period 2018-2021 in Romania. NO 2 data, both raster and time series obtained through remote sensing techniques by the TROPOMI sensor were used for this analysis. Kernel density estimation (KDE) was chosen as a technique to determine the magnitude of the spatial densification of the main sources of NO 2 pollution (KDE PS). Hotspot-Coldspot analysis of the NO 2 concentration based on Local Indicators of Spatial Association (LISA) was performed using Getis-Ord Gi* statistic. Besides, a correlation and regression analysis was conducted based on a statistical T-test between KDE PS, elevation above sea level, and mean tropospheric NO 2 concentration during 2018-2021. The results evidenced that traditional air pollution sources continue to determine the NO 2 pollution levels in Romania, these levels aside being also conditioned by the elevation above sea level. We conclude that NO 2 pollution can only be reduced in polluted areas if green energy is favored and measures are taken to mitigate polluting traffic in cities.