METODEAFPRØVNING AF PASSIVE DIFFUSIONSOPSAMLERE ...

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Measurements of atmospheric ammonia concentrations by two types of
passive diffusion tube samplers (ALPHA and Radiello) have been compared
to active measurements obtained by the denuder method. The
comparison was made at several locations over a one year period, covering
different concentrations levels and seasons. The passive diffusions
tube samples were found suitable for fortnight to monthly sampling.
Both types of passive diffusion tubes showed a small systematic overestimation
of the ammonia concentration compared to the denuder tubes
and therefore demand a correction. The precision is good and both types
of tubes are suitable for measuring local gradients. Since the passive diffusion
tubes are independent of power supply, they are very suitable for
monitoring purposes.
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