A 3-Dimensional analysis of long-range transported particulate matter to the Eastern Mediterranean: Implication for the chemical components of PM1 and PM10

This study aims to better characterize the location of the strong regional emitters of aerosols affecting the Eastern Mediterranean basin, through the use of a recently developed three-dimensional (3D) version of a Concentration Weighted Trajectory (CWT) model which can identify the prevalent transport pattern of polluted air masses as a function of their altitude (0 m ≤ Layer 1 < 1000 m (near ground layer), 1000 m ≤ Layer 2 < 2000m (intermediate layer), 2000m ≤ Layer 3 (upper layer)). Daily PM10 and PM1 chemical composition measurements from a regional background station on the island of Cyprus were incorporated in the model. Intrusions of PM1 constituents of an anthropogenic origin (Secondary Inorganic Aerosols (SIA) (SO42− and NH4+), K+, EC and OC), were mainly associated with Eastern continental airflows (Middle East regions) in Layers 1 and 2 during the cold periods (16 October to 15 April). During the warm periods (16 April to 15 October) the prevalence of Northern airflows in all layers mainly through Turkey enhanced the levels of SIA and K+ in PM1. Sea salt constituents in PM10 were particularly carried by West – Northwest Mediterranean airflows in all layers during both cold and warm periods. Dust intrusions from Northeast Africa and the Middle East were highlighted by episodes of PM10 crustal species and were most evident in Layer 1 during cold seasons. Therefore, this study reveals the spatial and vertical distribution of air masses transporting the main aerosol components at the Eastern Mediterranean.