Pollutants variability over the Kingdom of Saudi Arabia

Air pollution poses significant threats to ecosystems, public health, and urban areas. This study analyzed the spatiotemporal patterns of O₃, CO, NO_x, and SO₂ across Saudi Arabia (KSA), comparing industrial Al-Ahsa (east) with mountainous Al-Baha (west). Using CAMS data (2003–2023), we examined pollutant distributions and wind relationships across 15 pressure levels. O₃ peaks in summer (110 DU) due to high temperatures and subsiding air, with winter lows (70 DU). Summer O₃ is also influenced by vertical motion. CO concentrations are highest in winter (22 g/m²), linked to fuel combustion, and lowest in summer due to higher temperatures and elevated hydroxyl radicals. In the western region, NO_x peaks in summer (0.8 g/m²) and dips in winter/early spring. SO₂ is highest in autumn (1.4 g/m²) and lowest in summer. Eastern NO_x and SO₂ fluctuations are tied to local emissions and meteorology, with summer minima. CO shows the least variability, while SO₂ has the most, followed by NO_x and O₃. Trends reveal O₃ significantly increasing in southwestern KSA, CO generally decreasing but rising in the southwest and southeast, NO_x showing weak increases (except central decreases), and SO₂ increasing in industrial areas but declining broadly. These diverse trends highlight the strong regional impact of emissions and human activities on pollutant behavior across KSA.