In AHERA clearance monitoring, the specified number of samples is?

• A. 5 samples
• B. 20 samples
• C. 13 samples
• D. 10 samples

Answer: (C)

The main idea here is that AHERA clearance monitoring uses a fixed sampling plan to reliably decide if the air is clean after asbestos work. The protocol specifies a total of thirteen air samples to be collected as part of the clearance test. This total usually includes a set of interior samples that cover the work area to capture variation in fiber concentrations, plus one outdoor background sample to account for ambient asbestos levels not related to the work. Having thirteen samples provides enough data points to make a defensible clearance decision; too few samples could miss localized contamination, while this number keeps the testing practical and consistent with the regulatory procedure.