The Nederlandse organisatie voor Toegepast-Natuurwetenschappelijk Onderzoek (TNO) is currently estimating the predicting NH3 concentrations and reactive nitrogen is severly hampered by a lack of good emission timing in the chemistry-transport models (CTMs). The emission of NH3 varies locally and inter-annually as a result of local climate (temperature) and local agricultural management. Our research in the coming years will include deriving and testing parameterization of ammonia emissions for use in our chemistry-transport model LOTO-EUROS. A more realistic representation of the emissions will change the deposition patterns and hence may influence the most effective policies to protect nature reserves and reduce emissions. As part of thid development TNO will also focus on further increasing the spatial resolution of its model to more accurately represent local emissions and local depostions that can be of direct benefit to Component 1 of the 'Towards INMS' project.