Satellite-Detected Nitrogen Dioxide (NO2) Hotspots in the Greater Accra Region, Ghana

Burgeoning air pollution is a pressing public health concern. However, due to the scarcity and sparsity of ground-based monitoring, its impact remains uncertain. This work demonstrates how satellite-derived NO2 observations can identify persistent pollution hotspots and seasonal patterns in a data-scarce urban region. This work leveraged TROPOMI satellite data and Google Earth Engine to evaluate tropospheric NO2 hotspot patterns in the Greater Accra Region of Ghana from 2019 to 2023. TROPOMI data revealed persistent NO2 hotspots in urban and industrial areas, with overall peak concentrations reaching up to 3.3 × 1015 mol cm−2. Seasonal analysis showed elevated NO2 levels during the dry season, with a mean concentration of 2.3 × 1015 mol cm−2, while lower levels were observed during the rainy season. Increased emissions and reduced dispersion influence this pattern due to stable atmospheric conditions. Google Earth imagery confirmed that the highest NO2 concentrations were associated with the Heavy Industrial Area, highlighting the presence of extensive industrial facilities such as refineries, factories, and quarries. This integration of satellite observations with high-resolution geospatial tools provides a robust methodology for NO2 source attribution, emphasizing the need for targeted emission control measures in industrial zones to mitigate air pollution and associated health risks.