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ECN publication
Karakterisering van de regionale concentratievelden van ammoniak :monstername en meetstrategie
Published by: Publication date:
ECN 1995
ECN report number: Document type:
ECN-C--95-109 ECN publication
Number of pages: Full text:
40 Download PDF  

Five different samplers are tested for their appropriateness to determinemonthly average concentrations of ammonia in the ambient air. The samplers were diffusion tubes, which varied in their length and coverage, and a low-flow denuder. The measured results of those samplers were compared with the measured results of a reference continuous-flow denuder for different locations and during twelve periods of four weeks. Also, the impacts of meteorological conditions on the measurements were studied. Based on the accuracy of and agreement between the data of the samplers and the reference sampler it appeared that two types of passive samplers are very suitable for the measurement of monthly ammonia concentrations: a 7 cm diffusion tube, covered by a stainless steel gaze and a 3.5 cm diffusion tube, covered by a synthetic membrane. The last sampler will be used in a follow-up study to characterize regional concentration fields of ammonia. In order to develop a measurement strategy to characterize regional concentration fields of ammonia the spatial variability of the ammonia concentration in two areas of 5x5 km is investigated by means of model simulations and measurements. A minimum of 8 measuring points per area are required to realize an acceptable determination of the annually average ammonia concentration. 19 figs., 5 tabs., 10 refs., 2 appendices

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