New York State Asbestos Investigator Practice Exam

Under what circumstances must point counting be conducted in asbestos analysis?

1. If the materials are unpainted

2. When the fibers contain more than 10% asbestos

3. When PLM percentages are from 1-10%

4. In all cases of airborne samples

The correct answer is: When PLM percentages are from 1-10%

Point counting must be conducted in asbestos analysis in cases where polarized light microscopy (PLM) reveals percentages of asbestos that fall within the range of 1-10%. This is because the quantification of asbestos fibers at lower percentages requires a more precise counting method to ensure accuracy in determining the asbestos concentration within the material. Asbestos regulations often dictate that when the asbestos content is ambiguous or at a borderline level, such as 1-10%, point counting provides a systematic approach to confirm the percentage of asbestos present. This method is crucial for regulatory compliance and helps ensure that any necessary remediation actions or health precautions are based on accurate data. Point counting involves analyzing a specific area of the sample under a microscope and systematically counting the number of asbestos fibers present to generate a reliable estimate of the material's asbestos content. In contrast, other scenarios outlined in the choices may not necessarily require point counting, as higher concentrations may be apparent through gross examination, unpainted materials may not pose the same quantification challenges, and airborne samples have their specific protocols without necessarily using point counting alone.