Air pollution exposure and hotspots of CO, NO2, SO2, PM2.5, and aerosols in Iraq.

This paper presents a detailed subnational assessment of air pollution exposure and spatial hotspots of selected pollutants across Iraq between 2019 and 2024. Addressing the persistent lack of spatially and temporally consistent air quality data, the study integrates high-resolution remote sensing observations from the Sentinel-5P TROPOspheric Monitoring Instrument (TROPOMI) and hybrid ground-level PM2.5 data from the Atmospheric Composition Analysis Group (ACAG), focusing on key pollutants: CO, NO2, SO2, PM2.5, and aerosols. Population exposure to a combination of the five pollutants was quantified using the Global Human Settlement Population Layer (GHS-POP), enabling a robust evaluation of exposure disparities across governorates and districts. Spatial analysis employing the Getis-Ord Gi* statistic revealed distinct pollution hotspots. Urban centers such as Baghdad and Basra consistently exhibited elevated CO and NO2 concentrations (normalized scores > 6), primarily attributable to urbanization, vehicular traffic, and industrial activity. Major aerosol clusters were identified in areas prone to dust storms, notably Al-Muthanna (scores > 7.97), while the highest SO2 levels (scores > 7.11) were recorded in northern Iraq. Southern cities, including Basra and Nasiriya, emerged as PM2.5 hotspots with concentrations reaching up to 26 times the World Health Organization's recommended annual guideline, highlighting severe public health risks. In contrast, rural mountainous districts in the west and northeast showed significantly lower pollution exposure (composite air pollution score < 3.15, population exposure score < 1.82), underscoring marked regional disparities. These findings underscore the urgent need for localized interventions, including improved ground-level monitoring and early warning systems, to effectively address Iraq's critical air quality challenges and protect public health.