Which surface has the highest listed dust clearance limit among the given surfaces?

Which surface has the highest listed dust clearance limit among the given surfaces?

• A. Furniture, 40 ug/ft2
• B. Outside concrete, 800 ug/ft2
• C. Window sills, 100 ug/ft2
• D. Window wells, 100 ug/ft2

Answer: (B)

Dust clearance limits show how much lead dust is allowed to remain on a surface after cleanup, expressed in micrograms per square foot. A higher number means the standard is looser for that surface. From the given surfaces, outdoor concrete is listed at 800 ug/ft2, which is higher than furniture (40), window sills (100), and window wells (100). So outdoor concrete has the highest listed dust clearance limit. This difference reflects that outdoor and rougher surfaces often have higher baseline lead levels and are harder to clean to very low values, whereas smooth indoor surfaces like furniture and window sills are controlled to stricter, lower limits.

Dust clearance limits show how much lead dust is allowed to remain on a surface after cleanup, expressed in micrograms per square foot. A higher number means the standard is looser for that surface.

From the given surfaces, outdoor concrete is listed at 800 ug/ft2, which is higher than furniture (40), window sills (100), and window wells (100). So outdoor concrete has the highest listed dust clearance limit.

This difference reflects that outdoor and rougher surfaces often have higher baseline lead levels and are harder to clean to very low values, whereas smooth indoor surfaces like furniture and window sills are controlled to stricter, lower limits.