Aarhus University, DCE - Danish Centre for Environment and Energy, has prepared an overall assessment of the potential environmental impacts from a major release or spill of ammonia in relation to production and transportation of ammonia in a PtX plant or by shipping in Greenland. Three sites were included in the assessment: Kangerlussuaq (Sdr. Strømfjord), Kangerlussuatsiaq (Evighedsfjorden) and Nuup Kangerlua (Godthåbsfjorden). The overall findings shows that a large, worst-case ammonia spill could cause severe toxic damage to organisms during the passage of the ammonia cloud from within a few km to possibly more than 10 km from the source. This could lead to local loss of animal and plant abundance for some years. However, the ammonia will be quickly diluted and degraded and will not be transferred in the food web, and the mortality will not seriously impact plant and animal populations at a regional scale. There could be a fertilising effect of ammonia on the nutrient-poor terrestrial environment lasting for some years.