Nitrogen species and macroelements in aerosols over the Southern Baltic Sea

The annual cycle of atmospheric nitrogen species and macroelements (Na+, K+, Ca2+, Mg2+ and Cl−) over the south-eastern Baltic region was investigated. A one-year record enabled the variability of nitrogen species and macroelements in the aerosol over the coastal station at Hel to be traced. The highest concentrations of sea salt components were recorded in summer, while anthropogenic nitrate concentrations were highest in winter. When the air masses were of mixed marine and continental origin, the nitric acid reacted with coarse sea salt particles to form stable, coarse sodium nitrate. This seems to be a permanent removal pathway for nitrate. Anthropogenic aerosol species like NH+4 or NO− 3 formed by gas-to-particle conversion were generally associated with fine particles (<1 μm). Coarse particles like sodium or chloride resulted from resuspension from seawater.