Which condition must be met regarding electrostatic precipitator design?

Electrostatic precipitator design is fundamentally influenced by various parameters that directly affect its efficiency in capturing airborne particles. Among these parameters, both voltage and spacing play critical roles. The application of voltage generates an electric field that ionizes the particles as they pass through the precipitator, enabling their collection on charged plates. If the voltage is insufficient, the particles may not get adequately charged, leading to reduced capture rates.

Similarly, the spacing between the charged plates is significant. If the plates are too close, it can lead to a higher risk of sparking, whereas if they are too far apart, the efficiency of particle collection can be diminished. Hence, optimizing both the voltage applied and the distance between plates is essential for maximizing the performance of the electrostatic precipitator.

The other options do not account for the complexity of electrostatic precipitator design. While factors such as particle size and filter materials are relevant in the context of air filtration, they do not singularly capture the intricate dynamics of voltage and spacing that influence the effectiveness of an electrostatic precipitator system.