Estimation of emission data in Europe as input for long range transport calculations

For the 3D-Eulerian chemical transport model (CTM) of the troposphere developed and applied by the EURAD-project the aim of which is to investigate and forecast the tropospheric ozone formation and acid deposition in Europe an emission inventory has been established for SO$_{2}$ , NO$_{2}$, and volatile organic compounds (VOC). SO$_{2}$, NO$_{2}$, and VOC emissions from the power plants in Nest Europe are calculated from available data on installed power, on sulphur content of fuel used, and from estimated emission factors usin g the available data on emission modes. For NO$_{2}$ and VOC also the long distance road traffic is considered. The roads are considered as straight lines between the cities, and the line emission or the traffic volume is assumed to be proportional to the population number of the connected cities. Biogenic VOC emission was estimated based on forest distribution. The emissions are calculated in each of the grid elements used by the EU RAD model (80 by 80 km$^{2}$). The difference between these calculated emission data and the averaged annual emission data available on national level is distributed in the grid elements assuming that the residual emission is proportional to population density. Cities are considered as point sources the emissions of which are proportional to their population number. The rest of the total emission is distributed uniformly on the rural area taking in account the land distribution in each grid element. The comparison of this model with more sophisticated emission inventories available for some countries or regions shows the quality of the estimation for the countries where data are lacking. A simple estimate of the concentration of gaseous emitted pollutants as for example SO$_{2}$ is given using the emission data of these compounds on an European scale assuming that the chemical processes degrading these compounds can be parameterized by an exponentialdecay