Which statement about exposure assessment for continuous versus episodic releases is true?

• A. Continuous releases require long-term monitoring and modeling; episodic releases require event-driven sampling to capture peak exposures.
• B. Continuous releases require event-driven sampling.
• C. Episodic releases require long-term monitoring.
• D. Both rely on a single sample.

Answer: (A)

Exposure assessment depends on how the release behaves over time. A continuous release creates a relatively steady concentration, so it's important to collect data over long periods to understand long‑term averages and variability, and to use modeling that accounts for emission rate, ventilation, and dispersion to estimate sustained exposure. An episodic release, on the other hand, produces brief but potentially very high peak concentrations, so the sampling strategy focuses on capturing those peaks through event‑driven sampling timed around likely release events or upset conditions, sometimes with short‑term measurements or rapid response monitoring. A single sample won’t adequately represent either scenario because it can't reflect the temporal variability or the peaks, making long‑term monitoring plus modeling for continuous releases and targeted, event‑driven sampling for episodic releases the appropriate approach.