The Microparticle Performance Rating (MPR) is an air filter rating system created by the company 3M.
Because MPR was created by 3M, it only applies to filters produced by the 3M brand.
MPR is different from MERV, the Minimum Efficiency Reporting Value.
The MERV system measures a filter's ability to capture large particles.
The MPR only takes into account the microscopic particles between 0.3 and 1 μm.