Electrostatic precipitators are used to

Electrostatic precipitators (ESPs) are devices that are used to remove particulate matter from industrial exhaust streams. The principle of operation of an ESP involves the use of an electrostatic charge to attract and capture these particles.
An ESP consists of a series of plates that are charged with high-voltage electricity. As the industrial exhaust stream passes through the ESP, the particles in the stream become charged by the high-voltage electricity in the plates. The charged particles then become attracted to oppositely charged plates within the ESP and are captured on these surfaces. The captured particles can be removed from the ESP through a variety of means, such as by shaking or tapping the plates, or by using air or water to wash the particles away. The clean air is then released into the atmosphere.