Concentrations of Gaseous Elemental Mercury in the Atmosphere of a Mediterranean Coastal Site in Greece

Abstract

Gaseous elemental mercury (GEM) was monitored in the atmosphere of a coastal site situated in the Northern Aegean Sea of Greece from August 2014 to January 2015. The selected sampling site is seldom impacted by human activities. Thus, it was possible to study the processes involved in natural terrestrial, aquatic, and atmospheric environments. The diurnal and monthly variations in the concentration of GEM as well as the factors influencing these variations were determined. The GEM concentrations were found to be in the range from 0.63 to 4.44 ng m–3 during data acquisition. The mean GEM concentration was about 1.04 ±0.30 ng m–3. Higher concentrations and variability were observed during the summer than in fall and winter. In addition, increased GEM concentrations were measured during midday. The diurnal and monthly variations in GEM were possibly affected by solar radiation, temperature, vegetation, and boundary layer height. Various peaks were observed for air masses of terrestrial origin, possibly due to the small extent of biomass burning as well as rainfall. The background concentrations of GEM in the studied coastal site were around 1.50 ng m–3. The sampling site is a complex environment as this coastal region has seasonal surface water in the mainland and extended areas of grassland and vegetated surfaces. All individual parameters of this area play significant roles in determining GEM concentrations.