Risk of damage to crops in the direct neighbourhood of ammonia sources

In the Netherlands ammonia is emitted from several thousand sources (animal buildings, manured pastures, slurry storage facilities, etc.). Obviously, the ammonia concentrations are higher close to the source, but at this shor t distance vegetation has no special value in terms of nature conservation, as it mostly consists of ammonia-resistant agricultural crops. However, th ree crop categories include relatively sensitive species (fruity culture, g lasshouse crops and arboriculture). This paper presents an estimation of th e risk of ammonia damage to sensitive crops as related to the distance to t he source, based on the mean and variation in emission, dispersion, regiona l background concentration, landscape characteristics and plant sensitivity . Some attention is paid to damage of natural vegetation and to risk-reduci ng measures (elevation of emission point, wind fence around the source). Th e goal is to provide information for regional and local officials and farme rs who are dealing with risk evaluation, claims for damages, and environmen tal policy matters like stable reallocations etc.