SATELLITE-BASED ESTIMATION AND TREND ANALYSIS OF PM₂.₅ CONCENTRATION USING MODIS MAIAC AEROSOL OPTICAL DEPTH OVER THE UNIVERSITY OF BENIN, NIGERIA
DOI:
https://doi.org/10.33003/fjs-2026-1007-5261Keywords:
Aerosol Optical Depth, PM₂.₅, MODIS MAIAC, Harmattan, Trend Analysis, Remote SensingAbstract
Atmospheric aerosol pollution remains a major environmental and public health concern in rapidly urbanizing regions with limited air-quality monitoring infrastructure. This study developed a satellite-based framework for estimating and analyzing PM₂.₅ concentration over the University of Benin, Nigeria, using MODIS MAIAC Aerosol Optical Depth (AOD) data integrated with ground-based observations. High-resolution AOD data spanning 2015–2024 were processed within Google Earth Engine and calibrated using monthly PM₂.₅ measurements from two monitoring locations. A linear regression model produced a moderate positive relationship between AOD and PM₂.₅ (R = 0.54; R² = 0.29), indicating that approximately 29% of PM₂.₅ variability could be explained by aerosol loading. Although the explanatory power is moderate, such behaviour is common in humid tropical environments where cloud cover, aerosol mixing, atmospheric humidity, and boundary-layer dynamics weaken the AOD–PM₂.₅ relationship. Seasonal Mann–Kendall analysis revealed a statistically significant decreasing Harmattan AOD trend (p = 0.0031) with a Sen’s slope of −0.046 AOD per season. Estimated PM₂.₅ concentrations also exhibited decreasing seasonal trends ranging from approximately −0.997 to −1.20 µg/m³ per season across calibration approaches. The study demonstrates that satellite observations, when locally calibrated, can support seasonal aerosol monitoring and long-term environmental assessment in data-scarce tropical environments. The framework further highlights the potential of low-cost satellite-based air-quality surveillance for campus-scale environmental management and exposure assessment.
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Copyright (c) 2026 Stephen Olushola Oladosu, Tolulope Samuel Fawale, Kelvin Akere Moses, Rachael Omoniyepe Oladosu, Godsent Efosa Felix, Enobore Kelly Igbinidu, Mabel Eghemenrior Alenkhe
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