Impact of sea-salt emissions on the model performance and aerosol chemical composition and deposition in the East Mediterranean coastal regions

East Mediterranean region is often exposed to significant levels of particulate matter (PM), partly due to the natural emission sources surrounding the area. The complex coastal geography together with the high water coverage of the area implies important contribution of sea-salt aerosols (SSA) to the PM levels and composition. WRF-CMAQ air quality modeling system has been employed to simulate and quantify the impacts of SSA emissions on the model performance in the region. The results show up to one order of magnitude higher SSA emissions when surf-zone emissions are added. 10–20% improvements are calculated in terms of model discrepancies of PM10 mass with regards to the observations. SSA related particles (sodium (Na+) and chloride (Cl−)) are more realistically represented. The total nitrate (NO3−) partitioning ratio increases substantially up to 0.5 on average when SSA emissions are inserted to the model, leading to nitric acid (HNO3) levels decrease by more than 40% and total NO3− aerosols increase by more than an order of magnitude over the source areas. Adding surf-zone emissions over those from open-ocean increase PM10 deposition by up to 11% and wet deposition by around 1%. The results suggest that coastal areas are important sources of SSA emissions and can significantly alter the PM levels and composition in their vicinities.