Air cleaners are used to separate particles from air. Many air cleaners are like filters with a depth or absolute media to trap particulates. Some filters use media that will absorb any oil or moisture in compressed air to protect machinery.

Other styles of air cleaner include:
Electrostatic air cleaning is a two-step process. The air is first passed over electrically charged bars. These ionize particles entrained in the air. The air and particles are passed over a negatively charged plate. The electrostatic potential attracts the charged particles to the plate where they are held. Periodically the cleaner is powered off and the captured particles removed by blowdown, washdown or other means.

Vortex, sometimes called cyclone, air cleaners inject the dirty air into a vertical tube on a tangent. This creates a centrifugal effect that forces the particles to the outer wall where they fall to the bottom of the tube. Clean air exits at the top of the cleaner.

Additional air jets and baffles can help the cleaning efficiency.