Oceanologia (Mar 2001)
Selected ionic components of the marine aerosol over the Gulf of Gdañsk
Abstract
Aerosol samples were collected in May 1997 at a routine off-shore measurement station in the Gdansk Deep region and at Hel, the latter being a coastal station situated at the tip of the Hel Peninsula. Concentrations of NO3–, Cl–, Na+, Mg2+, K+ and Ca2+ were measured simultaneously at both stations. The sea influences the chemical composition of aerosols in the coastal zone of the Gulf of Gdansk regardless of season, time of day or direction of advection. Sodium chloride was always present in aerosols in the form of large particles originating from seawater. Besides the marine chloride and nitrate, additional amounts of these ions could have been of terrigenous origin. Sodium and chloride concentrations were dominant in the total mass of aerosols at both stations; however, these concentrations were three times higher at the marine station. Similarly, the concentrations of ions originating from seawater, like magnesium and calcium, were, on average, three times higher at the marine station. The chemical composition of aerosols and air over the Gulf of Gdansk was modified through the evaporation of chloride from the marine salt particles in reactions with gaseous nitric and sulphuric acids. A certain deficit of chloride versus sodium ions was noted. At the marine station the Cl–/Na+ ratio reached 0.89 ± 0.2, on average, while over the land station it was 0.93 ± 0.25, i.e. lower than the seawater standard.
