Long-term trends in OMI-retrieved NO₂ and SO₂ concentrations over the Arabian Peninsula

Tropospheric nitrogen dioxide (NO₂) and sulfur dioxide (SO₂) are critical for understanding air quality, atmospheric chemistry, and climate change. This study examines long-term trends in NO₂ and SO₂ concentrations over the Arabian Peninsula (AP) from 2005 to 2023 using Ozone Monitoring Instrument (OMI) data from NASA's Aura satellite, addressing the region's limited surface monitoring network. Elevated NO₂ (≥ 3 × 10¹⁵ molecules/cm²) and SO₂ (≥ 0.4 DU) concentrations are observed in urbanized and industrialized areas, including northeastern AP, western coastal regions, and eastern Saudi Arabia, driven by oil refining, power generation, and transportation activities. NO₂ trends reveal steady increases (∼0.1 × 10¹⁵ molecules/cm²/year) in industrial hubs like Kuwait City and Dubai. In comparison, declines (∼0.05–0.1 × 10¹⁵ molecules/cm²/year) occurred in regions such as western Saudi Arabia, southern Iraq, and Yemen, particularly post-2018, reflecting emission controls. Similarly, SO₂ trends increased (∼0.01 DU/year) in industrial hotspots but declined (∼0.005–0.01 DU/year) in areas influenced by regulatory measures and reduced shipping emissions. Regional analysis identified distinct trends in Target Areas (TAs). For example, TA1 (Dubai, Abu Dhabi) and TA2 (Qatar, Bahrain) exhibited early NO₂ growth followed by declines post-2015 and 2018. TA6 (Iraq) had the steepest NO₂ growth, which slowed post-2011, while TA5 (Iran) showed SO₂ growth until 2018, transitioning to a decline thereafter. This study underscores the importance of stringent air pollution controls in mitigating pollutant levels. It highlights regional variations in emission trends, offering critical insights for improving air quality across the AP.