Lead-based paint is defined by what concentration measured with an XRF analyzer?

Lead-based paint is defined by what concentration measured with an XRF analyzer?

• A. 1 mg/cm^2 using XRF
• B. 0.5% using laboratory analysis
• C. 1 mg/m^2 using XRF
• D. 5% using laboratory analysis

Answer: (A)

The main idea here is how lead in paint is defined when using an XRF analyzer. For on-site screening, lead-based paint is identified when the XRF reading shows 1 milligram of lead per square centimeter of painted surface. This per-area threshold is used because XRF provides surface concentration data, not a weight percentage. Why this is the best choice: it aligns with how XRF is used in the field—to quickly screen surfaces by measuring lead per unit area. The other options mix in laboratory-based percent-by-weight measurements or use incorrect units, which don’t correspond to how XRF readings are reported.

The main idea here is how lead in paint is defined when using an XRF analyzer. For on-site screening, lead-based paint is identified when the XRF reading shows 1 milligram of lead per square centimeter of painted surface. This per-area threshold is used because XRF provides surface concentration data, not a weight percentage.

Why this is the best choice: it aligns with how XRF is used in the field—to quickly screen surfaces by measuring lead per unit area. The other options mix in laboratory-based percent-by-weight measurements or use incorrect units, which don’t correspond to how XRF readings are reported.