The Medify Air MA-40 uses True HEPA H14 filters with 3 layers of filtration: pre-filter, H14 True HEPA and active carbon composite for odors. The high-efficiency True HEPA filter is tested to remove up to 99.99% of particles down to 0.1 mic. This higher-grade HEPA filter easily catches pollen, dust mites, mold spores and other tiny airborne particles you can't even see.