Volatile organic compounds (VOCs) in air from Nisyros Island (Dodecanese Archipelago, Greece): Natural versus anthropogenic sources

This study presents the chemical composition of VOCs in air and gas discharges collected at Nisyros Island (Greece). The main goal are i) to discriminate between natural and anthropogenic VOC sources and ii) to evaluate their impact on local air quality. Up to 70 different VOCs were measured in 6 fumaroles and 19 air samples collected from the Lakki caldera, where fumarolic emissions occur, and the outer ring of the island, including the Mandraki village and harbor. Air samples from the crater area show significant concentrations of alkanes, alkenes, cyclic, aromatics, and S- and O-bearing heterocycles directly deriving from the hydrothermal system, as well as secondary O-bearing compounds from oxidation of primary VOCs. At Mandraki village, C6H6/(methylated aromatics) and (linear)/(branched) alkanes ratios <1 allow to distinguish an anthropogenic source related to emissions from the outlet pipes of touristic and private boats.