Development and implementation of air pollution mitigation systems for animal husbandry in The Netherlands
Being one of the most densely populated nations in Europe, and housing an economically important livestock industry, the Netherlands face the challenge to strictly control environmental impacts of livestock production on residential and natural areas. The aim of this paper is to describe the main characteristics of the approaches followed in this policy with the focus on ammonia emission mitigation. It outlines technological developments and the implementation of mitigation technology in practice, and discusses benefits and drawbacks of the followed approach, and the possibility to make use of developed mitigation options in other regions with different productions settings. Since 1980 the ammonia emission from agriculture has been reduced by nearly 50%. This major achievement can be attributed to a number of general measures related to mandatory manure storage covering, low emission manure application techniques, and the implementation of low emission housing systems. Low emission housing systems have been developed for all main animal categories. Low emission is generally reached by restricting emitting surfaces, and quick removal and drying of manure. In general ammonia emissions were reduced by 50% and more, when compared to existing conventional systems. Higher reduction levels (70-90%) can be reached by air scrubbers. All measures were tested on practical farms using standardized measurement protocols. Low emission housing systems developed in one region cannot be simply transferred to other production regions. However, most of the mitigation principles that underlie these housing systems can be successfully applied in other settings as well, if modified and adapted to local conditions.
Air scrubbing techniques for ammonia and odor reduction at livestock operations : review of on-farm research in the Netherlands
Acid scrubbers and biotrickling filters have been developed for ammonia (NH3) removal at pig and poultry houses 
in The Netherlands over the last 20 years to prevent acidification and eutrophication of soils. Because of growing 
suburbanization, odor removal is increasingly considered important as well. In this review, we report the results of the on-farm 
research on full-scale operated scrubbers for treatment of exhaust air from animal houses with regard to NH3 and odor 
removal in The Netherlands. The NH3 removal of acid scrubbers ranged from 40% to 100% with an overall average of 96%. 
The NH3 removal of biotrickling filters ranged from -8% to +100% with an overall average of 70%. Minimum empty bed air 
residence times (EBRTs) were 0.4 to 1.1 s. For acid scrubbers, process control with pH measurement and automatic water 
discharge is sufficient to guarantee sufficient NH3 removal. For biotrickling filters, however, improvement of process control 
is necessary to guarantee sufficient NH3 removal. The odor removal of acid scrubbers ranged from 3% to 51% with an overall 
average of 27%. The odor removal of biotrickling filters ranged from -29% to +87% with an overall average of 51%. 
Minimum EBRTs were 0.5 to 2.3 s. Further research is necessary to explain this variation and to improve the odor removal 
efficiency of both acid scrubbers and biotrickling filters.
Acid rain research : do we have enough answers? : proceedings of a Speciality Conference, 's-Hertogenbosch, The Netherlands, 10-12 October 1994
Limitation of space allows only a selection of papers to be listed. Foreword. Acknowledgements. Conclusions. Opening Session. Opening remarks (A. van Alphen, Chairman Steering Committee Acidification Research). Atmospheric Deposition. Trace Gases. Long term measurement of SO 2 dry deposition over vegetation and soil comparisons with models (D. Fowler et al.). The use of the gradient method to monitor trace gas fluxes over forest: flux-profile functions for ozone and heat (J. Duyzer, H. Weststrate). Ammonia / Ammonium. Ammonia and ammonium in the atmosphere: present knowledge and recommendations for further research (W.A.H. Asman). Measurement and modelling of ammonia exchange over arable surfaces (M.A. Sutton et al.). Particle Deposition. Deposition of aerosol to coniferous forest (G.P. Wyers et al.). Microscopic processes governing the deposition of trace gases and particles to vegetation surfaces (J. Burkhardt). Generalization Total Atmospheric Deposition and Soil Loads Measurements and Models. On the determination of total deposition to remote areas (B.B. Hicks). Quantifying the scale dependence in estimates of wet and dry deposition and the implications for critical load exceedances (R.I. Smith, D. Fowler, K.R. Bull). Effects of Acid Deposition on Forest Ecosystems in The Netherlands. Effects of Acid Deposition on Forest Ecosystems in The Netherlands. Large scale impacts of acid deposition on forests and forest soils in The Netherlands. Ecological effects of atmospheric deposition on non-forest ecosystems in Western Europe (R. Bobbink, J.G.M. Roelofs). Future of Acidification Research. Today's Knowledge Is It Sufficient for Tomorrow's Decision Making Purposes? Lessons learned in acidification research: Implications for future environmental research and assessments (E. Cowling). Reliability of environmental information obtained by modelling and monitoring (J.A. Hoekstra et al.). Future Research Combination with Other Environmental Topics. Future of acidification research (T. Paces). Acidification and metal mobilization : effects of land use changes on Cd mobility (P.F. Romkens, W. de Vries). Posters. Critical Loads / Exceedances. Setting critical loads of acidity for dystrophic peat - a new approach (E.J. Wilson et al.). A comparison of models for the assessment of critical loads on different scales of observation (R.J.M. lenz, S. Mendler, R. Stary). wet Deposition / Throughfall. Eight years studying bulk and wet deposition in Spanish Basque country (D. Encinas, H. Casado). Scavenging of gases during growth of ice crystals (G. Santachiara, F. Prodi, F. Vivarelli). Dry Deposition / Concentrations. Dry depositions of acidifying and alkaline particles to forests: model and experimental results compares (W. Ruijgrok). Fine resolution modelling of ammonia dry deposition in Great Britain (R.J. Singles, M.A. Sutton, K.J. Weston). Miscellaneous.Carbon partitioning in Douglas-fir (E.G. Steingrover, M. Posma, W.W.P. Jans). The characteristics of acid precipitation in Southern China (T. Bai, X. Tang). List of Participants.