Name three common active air sampling media for VOCs and a brief use case.

• A. Sorbent tubes, silica gel beads, and filter papers; used to collect VOCs.
• B. Sorbent cartridges, activated carbon cloth, and diffusion badges; used to collect VOCs.
• C. Glass microchips, quartz beads, and metal canisters; used to collect VOCs.
• D. Sorbent tubes, charcoal tubes, and sorbent cartridges; used to collect VOCs for GC analysis.

Answer: (D)

Active air sampling of VOCs relies on pulling a known volume of air through a sorbent medium so the compounds are trapped for later analysis. The media used are sorbent tubes, charcoal tubes (activated carbon), and sorbent cartridges, which are all designed to be connected to a pump that draws air through them. After sampling, VOCs are released from the media by desorption (thermally or with solvent) and analyzed by GC or GC-MS to quantify exposure levels. A common use case is industrial hygiene monitoring: a worker wears a small pump with a sorbent tube, sampling air over a shift to capture VOCs such as benzene, toluene, ethylbenzene, and xylenes, providing data on occupational exposure. Other items listed, like diffusion badges, are used for passive sampling rather than active collection, and media such as glass microchips, quartz beads, or metal canisters aren’t standard active VOC collection media.