What are the requirements for clearance air monitoring required under AHERA?

• A. PCM - TEM - 0.01 f/cc, 70 structures =/< 260 sqft with 13 samples
• B. PCM - TEM - 0.01 f/cc, 50 structures =/< 260 sqft with 10 samples
• C. PCM - TEM - 0.02 f/cc, 70 structures =/< 260 sqft with 13 samples
• D. PCM - TEM - 0.01 f/cc, 70 structures =/< 270 sqft with 12 samples

Answer: (A)

AHERA clearance air monitoring requires a very strict fiber concentration limit and a defined sampling plan after asbestos abatement. The accepted clearance criterion is 0.01 fibers per cubic centimeter (f/cc). PCM is the standard method used to count fibers in air, and TEM may be used as a confirmatory or complementary analysis to verify results when needed. The sampling plan is tied to the project size; for a project involving up to 70 structures with a total area not exceeding 260 square feet, the plan calls for 13 air samples to demonstrate clearance. So the correct approach uses the 0.01 f/cc limit, PCM with TEM as applicable, and 13 samples for that scope. The other options differ in the limit, the number of structures, or the total area, which do not match AHERA's clearance requirements for this scenario.