The exergy method is used to compare different production processes and various methods for emission abatement with respect to their overall environmental impact. Some ammonium nitrate production processes are studied as examples, because the pollutants (ammonia and ammonium nitrate), emitted from these processes into the air and/or into the water, are really a feedstock and a product from the production process. Therefore, the essential result of the waste flows treatment is the recycling of the pollutants (ammonia and ammonium nitrate) back into the production process, decreasing simultaneously the exergy input and cumulative exergy consumption (C) 2010 Elsevier Ltd. All rights reserved.