Seasonal Study of Dust Deposition and Fine Particles (PM 2.5) in Iran Using MERRA-2 Data

The research results indicated that wet and dry dust deposition is a function of geographical characteristics. The seasonal wet and dry dust deposition and Fine Particles (PM 2.5) correlation in Iran with elevation, latitude and longitude results that the maximum correlation belongs to height, followed by latitude and longitude; meanwhile height and latitude are strongly and reversely correlated with each other. The Regional ratio of dry to wet deposition indicated that the share of dry deposition was high in south-eastern and western regions of Iran indicating the distance from dust sources. Wet and dry deposition fluxes of mineral dusts were both high in spring and summer low in clod season, showing similar seasonal variations to frequency of Aeolian dust events in Iran. The high amount of wet deposition in summer and autumn in northern regions (Mazandaran and Gilan Provinces) is due to the sea salt and anthropogenic factor dust that is washed out by local precipitation. Relatively high concentration of Fine Particles (PM 2.5) with different compounds in Iran is due to two factors: natural particles (mineral dust and sea salt) and anthropogenic activities (fossil fuel and biofuel). The maximum value of PM 2.5 can be seen in the south and southwestern regions of Iran due to local and trans-regional sources of sand and dust storms (SDS).