Atmospheric Ammonia, 2009 Detecting emission changes and environmental impacts. Results of an Expert Workshop under the Convention on Long-range Transboundary Air Pollution

1. Introduction PART I: AMMONIA CRITICAL THRESHOLDS 2. Reassessment of critical levels for atmospheric ammonia 3. Potential for the further development and application of critical levels to assess the environmental impacts of ammonia. 4. Long-term cumulative exposure exacerbates the effects of atmospheric ammonia on an ombrotrophic bog: Implications for Critical Levels. 5. The application of transects to assess the effects of ammonia on woodland groundflora. 6. Estimation of the ammonia critical level for epiphytic lichens based on observations at farm, landscape and national scales. 7. Mapping ammonia emissions and concentrations for Switzerland – effects on lichen vegetation. 8. Over which averaging period is the ammonia critical level most precautionary? 9. Machrolichens on twigs and trunks as indicators of ammonia concentrations across the UK – a practical method. 10. Assessment of critical levels of atmospheric ammonia for lichen diversity in cork-oak woodland, Portugal. PART II: TEMPORAL TRENDS IN ATMOSPHERIC AMMONIA 11. Linking ammonia emission trends to measured concentrations and deposition of reduced nitrogen at different scales. 12. Long-term record (1981-2005) of ammonia and ammonium concentrations at K-puszta Hungary and the effect of SO2 emission change on measured and modelled concentrations. 13. Assessment of NH3 and NH4+ trends and relationship to critical levels in the UK National Ammonia Monitoring Network (NAMN). 14. Review of published studies estimating the abatement efficacy of reduced-emission slurry spreading techniques. PART III: ANALYSIS OF AMMONIA HOTSPOTS 15. Ammonia deposition near hot spots: processes, models and monitoring methods. 16. Standardised grasses as biomonitors ofammonia pollution around agricultural point sources. 17. Soluble ammonium in plants as a bioindicator for atmospheric nitrogen deposition: refinement and testing of a practical method. 18. Spatial planning as a complementary tool to abate the effects of atmospheric NH# deposition at the landscape scale. PART IV: REGIONAL MODELLING OF ATMOSPHERIC AMMONIA 19. Modelling of the atmospheric transport and deposition of ammonia at a national and regional scale. 20. Application of a Lagrangian model FRAME to estimate reduced nitrogen deposition and ammonia concentrations in Poland. 21. Application of the EMEP Unified Model to the UK with a horizontal resolution of 5 x 5 km2. PART V: CONCLUSIONS AND OUTLOOK 22. Critical Levels for NH3. 23. Detecting change in atmospheric ammonia following emission changes. 24. Assessment methods for ammonia hot-spots. ( 25. Modelling the national and regional transport and deposition of ammonia. 26. Reliability of ammonia emission estimates and abatement efficiencies. 27. Ammonia policy context and future challenges. 28. Synthesis and summary for policy makers.