In the range of small particle sizes, the probability of separation decreases due to lower inertia, so that electrostatic charging of a generated water spray mist is suitable to improve the emission-reducing effect. Based on an application scenario, the separation mechanisms caused by inertia, turbulent mixing, and electrostatic attraction were studied to approximate the fractional separation efficiency. The approach illustrates the size-dependent dominance of the separation mechanisms and allows a qualitative comparison with practical results.