Characterizing Ambient Fine Particulate Matter Pollution in Jordan: National Monitoring Evidence of Spatial Inequality, PM_2.5 Hotspots, and Temporal Trends (2018–2024)

Fine particulate matter (PM_2.5) pollution is an important environmental challenge in rapidly urbanizing and industrializing regions; however, spatial inequalities, localized hotspots, and long-term trends remain insufficiently characterized in Jordan. This study evaluates ambient PM_2.5 variability across available locations within Jordan’s national air-quality monitoring network during 2018–2024, with emphasis on spatial distribution, hotspot identification, and temporal trends. Annual PM_2.5 observations from monitoring locations representing urban/residential, urban/traffic, industrial, and mixed industrial–urban environments were analyzed using descriptive statistics, non-parametric trend analysis, and comparative statistical tests. The study identified substantial spatial variability among monitoring locations, with several of the highest concentrations observed in industrial and mixed industrial–urban environments, although elevated concentrations were also observed in urban settings. Industrial-related sites showed a mean PM_2.5 concentration of 26.51 µg/m³ compared with 29.24 µg/m³ for urban-related sites; however, the difference was not statistically significant (Mann–Whitney U=297,p=0.604), indicating that elevated PM_2.5levels are influenced by multiple emission environments rather than industrial classification alone. Temporal analysis indicated a declining trend during 2018–2024, with a Sen’s slope of −1.67 µg/m³/year, although interpretation should consider the progressive expansion of monitoring coverage. Significant governorate-level differences demonstrated clear spatial inequality in PM_2.5 distribution, highlighting the need for targeted monitoring and location-specific air-quality management strategies in Jordan.