High-efficiency particulate air or HEPA is a type of air filter. Filters meeting the HEPA standard have many applications. To qualify as HEPA by US government standards, an air filter must remove at least 99.97% of all particles greater than 0.3 micrometers from the air that passes through the filter. Omni CleanAir branded HEPA filters ensure our machines operate at peak CFM rates. All OCA HEPAs align with our exclusive TrueCFM standards. When OCA specifies a machine's capability to achieve the designated CFM, with the right setup, you can rely on that level of air exchange for your project's CFM calculation and the machine's performance.