What's the difference between a HEPA, activated-carbon, and standard cabin filter?

Standard particulate filters trap dust and pollen; HEPA-style filters claim finer particulate capture; and activated-carbon filters add a layer that helps reduce odors, smog, and exhaust smells. Several listings here combine HEPA-style media with activated carbon, marketing both particulate and odor control, though none of the supplied signals included independent lab verification of those filtration claims.