Ruimtelijke verdeling van ammoniakconcentraties inNederland gemeten met passieve samplers

To obtain a spatial distribution of the ammonia concentrations in the Netherlands measurements of ammonia have been performed on a grid of 15 x 15 km (159 locations) with passive samplers from September 2000 until September 2001. The highest ammonia concentrations represented by the grid are observed in all months in the East of Noord-Brabant and the North of Limburg with yearly average concentrations of 15 ug/m3. Elevated concentrations of about 10 ug/m3 are seen in the Gelderse Vallei, the Achterhoek and Twente and concentrations of about 7 ug/m3 are seen in central Overijssel and Friesland. De monthly ammonia concentrations averaged over the Netherlands varied from 4 ug/m3 in fall of 2000 to 9.6 ug/m3 in May 2001 with a yearly average of 6.6 ug/m3. The yearly average concentration calculated from the 159 measurement locations yields also 6.6 ug/m3, while the average on the eight LML-locations is higher with 7.8 ug/m3.