What is a P-100 filter?

• A. A carbon filter
• B. A HEPA filter that is oil-proof (P-100)
• C. A ceramic filter
• D. A charcoal adsorption filter

Answer: (B)

P-100 is a respirator filter for particulates that is oil-proof and provides high-efficiency filtration. The “P” means it’s resistant to oil-containing aerosols, and the “100” signifies 99.97% filtration efficiency for particles, which is the HEPA-class level. This makes it suitable for filtering very fine dust, smoke, and other aerosols—even in oily environments. It does not filter gases or vapors, so gas/vapor cartridges would be needed for those.

So the best description is a HEPA-class filter that is oil-proof (P-100). Carbon or charcoal filters target gases and odors, not particulates; a ceramic filter isn’t the standard P-100 description, and adsorption filters alone don’t capture particles the way a P-100 does.