| 摘要 |
The device comprises, in a recessed base 1, a housing 1a for accommodating an absorbent material which is held therein by a first grid 2, the whole being covered by a hood 3 fitted with a second grid 4 and defining between the two aforementioned grids a space 23 for diffusion of the surrounding air. The depth of the diffusion space, which determines the diffusion distance, is defined by a spacer 6 interposed between the inner upper face 3a of the hood 3 and the first grid 2. Use for sampling chemical pollutants under precise conditions. <IMAGE>
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