ATMOSPHERIC NITROGEN DEPOSITION TO THE NORTH-SEA

The groups of nitrogen components that contribute most to the eutrophi cation of the sea are ammonia, nitrogen oxides and their respective re action products, The emission of ammonia is mainly from animal husband ry, whereas the emission of nitrogen oxides is mainly from combustion processes, Ammonia reacts in the atmosphere to form particulate ammoni um, Nitrogen oxides react to form nitric acid, nitrous acid, particula te nitrate and peroxy-acetyl nitrate, The various nitrogen components have different physical and chemical properties, Therefore, their dry and wet deposition velocities differ, The dry deposition velocity of g as to the sea depends on its solubility, reactivity, concentration in seawater and the wind speed, The dry deposition velocity of a particle depends on its size and the wind speed, The wet removal rate is a fun ction of meteorological conditions, For a gas it further depends on th e solubility and reactivity of the gas, For a particle, it further dep ends on the particle's ability to act as a condensation nucleus for pa rticles, The total deposition of ammonia and its reaction products to the North Sea is about 140 kt N a(-1). The total deposition of nitroge n oxides and their reaction products is about 200 kt N a(-1).