Composition of particulate matter (PM) originated from desert dust storms in the Eastern Mediterranean region

摘要

Dust storms are naturally occurred events that transport dust particles far from the desert of origin and can reach the Americas, Europe, Mediterranean, and Middle East. These events occur several times per year in the Mediterranean region and have been associated with increased cardiovascular and respiratory mortality and hospital admissions. However, it is still not clear which component(s) of dust particles are associated with human health effects, mainly due to lack of information on the organic and inorganic composition of the dust particles. Therefore, we collected PM samples, in presence and absence of dust episodes, from two cities in the Eastern Mediterranean region (fine and coarse PM from Limassol, Cyprus; fine PM from Heraklion, Greece), and analyzed them for mass, elemental and organic carbon, secondary inorganic ions, metals, and polycyclic aromatic hydrocarbons(PAHs). Heraklion samples were classified based on the origin of the blowing air mass in three categories: a) pure dust (PD), when air was blowing directly from Sahara/Middle East desert; b) mixed dust (MD), when air mas originating from Sahara/ME desert and passing from other European countries before reaching the sampling site; and c) non-dust (ND). Limassol samples were classified to dust (DD) and non-dust (ND) because of small sample size. During dust storms, both fine and coarse mass increased from two to five times higher than ND days; the highest mass concentrations were observed during PD days. On overall, dust storms had a high impact on mineral dust PM mass (defined as the sum of the oxide forms of crustal elements) and ΣPAH were in higher concentrations during ND than DD for both locations and PM size. However, ΣPAH were found higher when dust plume was passing from other European countries (median_(MD) = 1.21 ng/m~3) as opposed to blowing directly from Sahara desert (median_(PD) = 1.04 ng/m~3). This classification (PD versus MD versus ND) can be useful for future studies and risk assessments.