Cost-effective strategies for reducing nitrogen deposition in Europe

This paper explores the potential cost savings which would result from a combined control of emissions of nitrogen oxides and ammonia for the cost-effective achievement of nitrogen deposition targets in Europe. Based on the Regional Acidification Information and Simulation (RAINS) model, a framework has been constructed for a simultaneous optimization of nitrogen oxides and ammonia emission reductions using nitrogen depositions from both pollutants as side constraints. The paper first demonstrates that the same nitrogen deposition resulting from the currently committed reductions of emissions of nitrogen oxides (without measures for ammonia emissions) can be achieved at only 55% of the costs if measures for ammonia reduction would also be applied. The analysis shows that no large scale substitutions of reductions of nitrogen oxides by ammonia measures occur. The cost savings mainly result from replacing the most expensive (and ineffective) nitrogen oxide abatement at a few places in Europe with inexpensive ammonia control measures. Consequently, the total level of emissions of nitrogen oxides is hardly higher than in the reference case, but substantial ammonia reductions are implemented lowering total cost. The second case explores the potential contribution ammonia control can make to attaining the same nitrogen deposition levels resulting from the maximum application of nitrogen oxide abatement technologies solely. In this case, reductions of ammonia emissions can lower total abatement costs by 23%, basically by modified manure handling, stable adaptations for poultry, and the control of industrial ammonia emissions