How do HEPA filters and carbon adsorbers differ in air filtration?

• A. HEPA removes gases; carbon adsorbs particulates.
• B. HEPA removes odors; carbon adsorbs radiation.
• C. HEPA removes particulates; carbon adsorbs volatile organic compounds and some gases.
• D. HEPA adsorbs VOCs; carbon removes bacteria.

Answer: (C)

The key idea is that filtration media target different types of contaminants. HEPA filters work by physically trapping solid particles as air passes through a dense mat of fibers, using mechanisms like diffusion, interception, and impaction. This makes them excellent at removing dust, pollen, mold spores, and other particulates, but they don’t remove gases or odors. Activated carbon adsorbers, on the other hand, use a highly porous carbon surface to attract and hold gas-phase molecules, so they’re effective for odors and many volatile organic compounds (VOCs) and some other gases, though they don’t reliably remove particulates or microbes. Because of these distinct roles, the correct description is that HEPA removes particulates while carbon adsorbs VOCs and some gases.