Which scenario best calls for area sampling?

• A. Assessing an individual's risk for a specific task.
• B. When monitoring PPE effectiveness.
• C. Evaluating overall ambient concentrations in a workspace and identifying source areas.
• D. Measuring a worker’s monthly exposure to a contaminant.

Answer: (C)

Area sampling is used to characterize ambient air conditions across a workspace, providing a picture of the general environment and where contaminants originate. By placing samplers at fixed locations, you can map concentrations, spot hot spots, and identify source areas, which is essential for evaluating overall environmental levels and targeting controls such as ventilation improvements or source mitigation. The other scenarios focus on individual exposure rather than the space's ambient conditions: assessing risk for a specific task targets a single worker’s potential exposure during that task; measuring a worker’s monthly exposure sums exposure over time for one person; and evaluating PPE effectiveness usually requires knowing how much contaminant actually reaches the worker, which is best assessed with personal exposure monitoring rather than ambient area data.