Air and liquid enter the atomizing nozzle under pressure. The air moves through the nozzle under pressure and meets the liquid at the nozzle tip, causing the formation of spray droplets that are 30 to 60 microns in diameter. At the tip of the nozzle is a tiny electrode which applies an electrical charge to the spray. The electrical charging causes a natural force of attraction between the spray droplets and target surface, similar to the attraction between items of clothing created by the tumbling of a clothes dryer. The attraction to the target's surfaces relates to Coulomb's Law, which states that any two charged objects will create a force on each other. The charge on the droplets, though small, pulls the spray towards the target at 75 times the force of gravity. The spray droplets can reverse direction, moving against gravity, to coat all sides of an object.
ESS takes advantage of the principal of physics to achieve better coverage and to lessen the environmental impact by allowing smaller amounts of chemicals to be used. In addition ESS uses air-assistance to help with spray delivery. Air is necessary in electrostatic spraying to create tiny droplets (30-60 microns, 900 times smaller than conventional sprayers) that can travel in the turbulent airstream into dense areas.