Atmospheric deposition of nitrogen compounds in the Czech Republic

This study presents estimates of dry and wet deposition of nitrogen compounds in the Czech Republic. Deposition has been estimated from monitored and modelled concentrations in the atmosphere and in precipitation, where the most important nitrogen compounds are nitrogen oxides and ammonia, and their reaction products. Measured atmospheric concentrations of NOx, NH3 and of aerosol particles (NO3− and NH4+), along with measured concentrations of NO3− and NH4+ in precipitation, weighted by precipitation amounts, were interpolated with a properly used Kriging technique on a 10 × 10 km grid covering the whole Czech Republic. Wet deposition was derived from concentration values for NO3− and NH4+ in precipitations and from precipitation amounts. Dry deposition was derived from concentrations of gaseous components and aerosol in the air, and from their deposition velocities. A resistance model was used for calculating NOx, NH3 deposition velocities; deposition velocities of HNO3 were derived from the literature and deposition velocities of particles were parameterized. The annual average NOy deposition in the Czech Republic in 1994 was estimated at 972 eq H+ ha−1 a−1 and the annual average NHx deposition at 887 eq H+ ha−1 a−1.