Comparative Analysis Of Air Quality In Urban And Rural Environments Using Satellite And Ground Observations In Nigeria

Abstract

Air pollution poses a persistent environmental and health threat in developing regions, particularly across sub-Saharan  Africa, where rapid population growth, industrialization, and inadequate monitoring infrastructure limit effective control.  This study employed an integrated approach, combining satellite observations and ground-based measurements, to  examine the spatial and temporal dynamics of three major pollutants particulate matter (PM₁₀), ozone (O₃), and nitrogen  dioxide (NO₂) across five Northern Nigerian states: Abuja, Bauchi, Plateau, Gombe, and Nasarawa, covering the period  from October 2022 to September 2024. Data obtained from MODIS and Sentinel-5P TROPOMI were analyzed alongside  local station records to investigate seasonal variations, spatial distribution patterns, and the relationship between satellite  and surface observations using Kriging interpolation in ArcGIS.  The findings reveal significant spatial variability and strong seasonal influence. PM₁₀ and PM₂.₅ concentrations peaked  during the dry Harmattan season due to intense dust transport, biomass burning, and poor atmospheric dispersion. Abuja  and Gombe recorded extreme PM₂.₅ levels of 402.1 µg/m³ and 222.7 µg/m³, respectively far above the WHO guideline of  15 µg/m³ while Plateau consistently exhibited lower concentrations (11–20 µg/m³) due to its elevation and cleaner air  mass inflow. Aerosol Optical Depth (AOD) followed a similar distribution, with Gombe showing the highest value (2.803  in February 2024). O₃ levels were highest during the dry months, reaching 282.6 µg/m³ in Abuja, while NO₂ exhibited  clear urban–rural contrasts, peaking at 84.2 µg/m³ in Bauchi during December 2022. Correlation analysis indicated  moderate satellite ground agreement (r ≈ 0.6 in Abuja), although satellite data generally overestimated surface  concentrations. Kriging interpolation revealed strong spatial autocorrelation (range ≈ 120 km; RMSE ≈ 12 µg/m³) and  effectively delineated high-pollution zones around major industrial and traffic corridors.  Overall, the study demonstrates that seasonal meteorology, dust intrusion, and anthropogenic activities are key drivers of  air quality fluctuations in selected states in Nigeria. The integration of satellite and ground-based monitoring improves  spatial coverage and enhances understanding of pollutant dynamics in data-limited environments. Strengthening  monitoring infrastructure, calibrating satellite retrieval algorithms, and implementing emission-control policies are critical  for advancing clean-air initiatives and protecting public health across the region.