The removal efficiency of oil particles smaller than one micron in size drops off rapidly. Mist collectors remove most of the oil mist but not the finer aerosols without the use of after filters. Many fine aerosols come from aqueous coolants, which is the newer cooling technology. Most mist collectors are compact, easy to install and have continuous drain of the oil and coolant that is being removed. Many applications are the direct attaching to metal cutting machines, where the mist of the cooling oil or aqueous coolants is gathered and fed back into the cooling cycle.

The multi filter oil mist collector systems use metal mesh coalescing filters and fiber spun bound cartridges that are bag shaped or pleated. These filters are large in size and are used in sequence to efficiently remove oil mist and aerosols. The disadvantage is the need for removing and cleaning the filters. This requires downtime to allow the oil to drain from the filters. The advantage of this type of mist collector is larger air volumes and higher particle removal efficiency up to 99.97% of particles of 0.5 micron size