| Popis: |
Publisher Summary Sampling of atmospheric trace gases using conventional denuders is a laborious task. Because it involves many manipulations in the field and the laboratory, the precision of this technique is limited. Automation of the technique increases its precision and offers the possibility to perform measurements over a long period, which allows a study of seasonal and daily influences on concentrations and fluxes. Initially, emphasis was placed on the development of thermodenuders. Thermodenuders for ammonia, in which NH 3 is collected on a V205 coating and partly converted to NO by heating and detected by an NO monitor, were used to study dry deposition over a forest (Speulderbos) for a period of five months. The relative precision of these instruments is 5% for concentrations of 1–20 g/m 3 . Another line of development involved wet denuders in which trace gases are collected in a solution film on the walls of an annular, rotating denuder. The denuder is automatically emptied and refilled. |
