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<p>Air pollutants significantly impact both humans and the environment. This study quantifies the levels of seven major air pollutants, namely, carbon monoxide (CO), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), ozone (O₃), formaldehyde (HCHO), the aerosol index (AI), and methane (CH₄), across 15 cities in Ethiopia. Satellite-based measurements of atmospheric pollutants were downloaded from the Tropospheric Monitoring Instrument (TROPOMI), which offers a spatial resolution of 5.5 × 5.5&#xa0;km. The data were accessed via the Google Earth Engine platform for preprocessing, which included cloud filtering, the exclusion of pixels whose quality assurance flags failed and temporal aggregation. The datasets were standardized into a unified spatial grid format and prepared for integration within the Monte Carlo simulation, principal component analysis (PCA), and t test statistical frameworks. The results revealed spatial heterogeneity in atmospheric pollutant concentrations across Ethiopian cities. Gambella, Semera, and Jijiga have consistently been identified as high-pollution hotspots because of their relatively warm climates and relatively warm vegetation, which can absorb atmospheric pollutants. Gambella and Semera emerged as critical hotspots due to combustion-related and dust-driven emissions, whereas cities such as Dessie and Jijiga presented comparatively lower pollution burdens. With the exceptions of Semera, all cities have a negative AI index. This negative aerosol index has less capacity to absorb ultraviolet (UV) radiation. The AI in Semera varies from − 0.3 in the month of October to 0.57 in April and June, with a mean annual value of 0.04. Elevated levels of CO were detected in cities such as Gambella and Asosa, indicating the likely influence of intensive fuel combustion, possible biomass burning, and increased temperatures that contribute to HCHO production. Carbon monoxide, ozone, nitrogen dioxide, and formaldehyde all presented p values below 0.05, indicating that their mean concentrations differed significantly between low and high air quality conditions. The results revealed a highly heterogeneous spatial distribution of air pollution risk, contradicting the common belief that pollution levels increase directly with the intensity of urbanization. This study underscores the importance of city-specific pollutant mitigation strategies.</p>

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Air quality evaluation in Ethiopian major cities through Monte Carlo simulation, principal component analysis, and T test-integrated statistical frameworks

  • 期刊论文

  • 发表日期：

    2026年4月1日

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  • Mehmet Ali Çelik,
  • Melahat Batu Ağırkaya,
  • Mitiku Badasa Moisa,
  • Dessalegn Obsi Gemeda

摘要

Air pollutants significantly impact both humans and the environment. This study quantifies the levels of seven major air pollutants, namely, carbon monoxide (CO), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), ozone (O₃), formaldehyde (HCHO), the aerosol index (AI), and methane (CH₄), across 15 cities in Ethiopia. Satellite-based measurements of atmospheric pollutants were downloaded from the Tropospheric Monitoring Instrument (TROPOMI), which offers a spatial resolution of 5.5 × 5.5 km. The data were accessed via the Google Earth Engine platform for preprocessing, which included cloud filtering, the exclusion of pixels whose quality assurance flags failed and temporal aggregation. The datasets were standardized into a unified spatial grid format and prepared for integration within the Monte Carlo simulation, principal component analysis (PCA), and t test statistical frameworks. The results revealed spatial heterogeneity in atmospheric pollutant concentrations across Ethiopian cities. Gambella, Semera, and Jijiga have consistently been identified as high-pollution hotspots because of their relatively warm climates and relatively warm vegetation, which can absorb atmospheric pollutants. Gambella and Semera emerged as critical hotspots due to combustion-related and dust-driven emissions, whereas cities such as Dessie and Jijiga presented comparatively lower pollution burdens. With the exceptions of Semera, all cities have a negative AI index. This negative aerosol index has less capacity to absorb ultraviolet (UV) radiation. The AI in Semera varies from − 0.3 in the month of October to 0.57 in April and June, with a mean annual value of 0.04. Elevated levels of CO were detected in cities such as Gambella and Asosa, indicating the likely influence of intensive fuel combustion, possible biomass burning, and increased temperatures that contribute to HCHO production. Carbon monoxide, ozone, nitrogen dioxide, and formaldehyde all presented p values below 0.05, indicating that their mean concentrations differed significantly between low and high air quality conditions. The results revealed a highly heterogeneous spatial distribution of air pollution risk, contradicting the common belief that pollution levels increase directly with the intensity of urbanization. This study underscores the importance of city-specific pollutant mitigation strategies.