Cost-effective means of reducing ammonia emissions from UK agriculture using the NARSES model

To comply with International agreements to improve air quality, signatory states need to reduce emissions of ammonia (NH 3). Since the majority of NH 3 emissions come from agriculture, measures may need to be implemented by the farming industry. Member states of the EU will, by 2010, require large pig and poultry production units to reduce NH 3 emissions to comply with the integrated pollution prevention and control directive (IPPC). The NARSES model uses a mass-flow method to estimate NH 3 emission from UK agriculture and to identify the most cost-effective means of reducing NH 3 emissions. Model runs were carried out to assess the likely impact of the IPPC Directive on UK NH 3 emissions and the sensitivity of model output to input data on the costs and abatement efficiencies of proposed abatement measures. The impact of the IPPC Directive is likely to be small, offering a reduction of c. 8700 t, 3.5% of total UK agricultural NH 3 emissions. Even large (30%) changes in our estimates of cost or changes of 10% in our estimates of abatement efficiency will make little difference to the ranking of abatement techniques according to cost-effectiveness. The most cost-effective reductions may be achieved by replacing urea fertilizer with ammonium nitrate, immediate incorporation of manures and slurries to tillage land by discs, storing all FYM and poultry manures before spreading to land and applying slurries to grassland by trailing shoe.