Distinguish between personal sampling and area sampling in industrial hygiene and when each is appropriate.

• A. Personal sampling measures ambient concentrations in the space.
• B. Area sampling measures a worker’s actual exposure.
• C. Personal sampling measures a worker’s actual exposure; area sampling measures ambient concentrations in a space.
• D. Personal sampling is used for area compliance testing only.

Answer: (C)

The main idea is that personal sampling captures what a worker actually inhales, while area sampling measures the contaminant level present in the surrounding environment. A sampler worn in the worker’s breathing zone directly reflects exposure during the task, accounting for how long they are in a space, how they move, and whether PPE or respirators are used. In contrast, fixed monitors in a room or area measure ambient concentrations in that space, which helps characterize the general air quality and identify sources or areas where ventilation may need improvement.

This is why the best answer states that personal sampling measures a worker’s actual exposure, and area sampling measures ambient concentrations in a space. Use personal sampling when you need to quantify individual exposure for risk assessment or regulatory compliance; use area sampling to understand environmental concentrations for ventilation design, source control, or to map where contaminants are most concentrated—information that may not directly translate to a specific worker’s dose.