Electrostatics is put to good use in a wide variety of applications. For examples, the electrostatic precipitator enables smoke emissions from power-station chimneys, smelting plants, and other industrial plants to be reduced to relatively low, acceptable levels. On a smaller scale, efficient filters exist for removing dust from the air in offices, public places, and the home. In some filters, dust particles undergo corona charging as they are sucked by a fan through a duct, and are then collected on grounded electrodes; in others, permanently electrified filter material is used, made from thin plastic sheets which have been treated by surface bombardment from a corona ion source.
In several applications which utilize electrostatics, solid or liquid particles
are charged and sprayed onto grounded objects. Dry powder coating is
used in many industries in preference to the wet-paint-spraying process.
Crop spraying is another important application in which electrostatic
forces help to efficiently apply herbicides or insecticides.