Faster Sampling Rates and High Capacity Offer Advantages
By Kristen L. Schultz

Passive sampling offers advantages over active sampling in that the passive sampling devices do not require an air sampling pump and calibration. Classic passive sampling devices have a two-dimensional geometry with a flat adsorbing surface and are known as axial-type samplers. Since 1990, radial passive sampling devices have emerged that have a 360-degree adsorbing surface. By nature of this radial symmetry, the uptake rates are two to three times higher compared to axial diffusive samplers.
Sampling for Formaldehyde with Radial Passive Sampling Devices
Figure 1. The axial sampler shown on the left has only one diffusive surface. The radial-type sampler on the right has a 360-degree diffusive surface.
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