Ammonia and methane emissions from a dairy farm in Segovia (Spain)

A large proportion of the NH3 emitted locally is deposited in the immediate neighbourhood of the source rather than transported over long distances. A realistic distribution of NH3 sources and sinks requires quantitative information on the spatial location of the emission sources, as well as emission estimates, suitable spatial resolutions and the acquisition of data in different climatic conditions. Very few of the studies carried out in southern Europe show the distribution of NH3 emissions around point sources. In general, ammonia gas deposits close to the emission source. Studies in the surroundings of a poultry farm in UK reported NH3 deposition fingerprints of less than 1 km. In Spain, the ammonia concentration field around a laying hen farm decreased to levels of 3-5 mu g/m(3) (background levels for the area) within distances of less than 600 m, whereas at the same distances around a broiler meat farm the concentration levels were double. The aim of this paper was to determine the NH3 concentrations in the surroundings of a dairy farm in Spain, since no measurements around this type of farm are available, and to combine these measurements with estimates of the ammonia fluxes from the same farm. The ammonia concentrations were determined by passive samplers placed 2 m above the ground at 60 sampling points. To estimate the fluxes from the farm buildings, continuous measurements with an Innova (mod. 1412-5) were performed at different points. The concentrations near the stable showed a maximum of 150 mu g/m(3) and decreased to 23 mu g/m(3) within 200 m; the wind direction determined the shape of the plume. The background concentrations were estimated to be 5 mu g/m(3). The estimated NH3 emissions from the stable were 10.5 kg of NH3/cow/yr, which are lower levels than the ones used for the Spanish inventory. In addition, CH4 emissions were also estimated (79 kg of NH3/cow/yr).