Spatiotemporal Analysis and Climatological Drivers of <scp> PM _2.5 </scp> Pollution in Saudi Arabia

ABSTRACT Fine particulate matter (PM 2.5 ≤ 2.5 μm) poses a significant environmental and public health challenge in Saudi Arabia, where sparse ground‐based monitoring stations hinder comprehensive assessments of PM 2.5 hotspots, trends and impacts. Climate change is expected to exacerbate air quality by influencing atmospheric circulation, dust storm frequency and pollutant dispersion. Therefore, this study focuses on identifying pollution hotspots, temporal variations, calculating trends and factors influencing PM 2.5 pollution, along with source and transport pathways using Washington University‐based newly updated Global Estimates (V6.GL.02) of monthly PM 2.5 , the second version of Modern‐Era Retrospective analysis for Research and Applications (MERRA‐2), and ERA5 reanalysis data. In addition, future projections of PM 2.5 components, specifically dust, were analysed using the ensemble mean of five CMIP6 Global Climate Models (GCMs) under the Shared Socioeconomic Pathways (SSP: 1–2.6, 2–4.5 and 5–8.5) from 2023 to 2100. Results show consistent spatial patterns annually and seasonally, with PM 2.5 hotspots (annual mean &gt; 60 μg/m 3 ) identified over eastern Saudi Arabia, the Riyadh metropolitan area, coastal Makkah, Madinah and Tabuk. Notably, PM 2.5 across all 13 provinces exceeded the annual limits of Saudi Air Quality Standard (SAAQS ≤ 15 μg/m 3 ), World Health Organization (WHO) AQS (WHOAQS ≤ 5 μg/m 3 ) and European Environmental Air Quality Standard (EEAQS ≤ 12 μg/m 3 ) by factors of 2–4, 7–12 and 3–4 times, respectively. Pearson's correlation and multiple regression analysis demonstrate that various climate variables across Saudi Arabia significantly influence PM 2.5 . Annual and seasonal PM 2.5 increased during 2001–2010 and 2000–2022 but declined between 2011 and 2020. PM 2.5 is primarily influenced by dust, followed by black carbon (BC), sulfate and sea salt, originating from local sources, neighbouring regions (e.g., Iraq, Kuwait and Syria), and distant regions such as North/East Africa and South Asia. Dust is projected to increase in 2030–2049 under all SSPs. In 2050–2069, they continue to rise under SSP1‐2.6 and SSP2‐4.5 but decline under SSP5‐8.5. By 2070–2100, dust decreases under SSP1‐2.6 while increasing slightly under SSP2‐4.5 and SSP5‐8.5. This study underscores climate‐driven PM 2.5 risks and transboundary contributions, urging targeted mitigation in Saudi Arabia.