How does an electrostatic air filter operate?

An electrostatic air filter operates by utilizing charged grids to attract and capture airborne particles. In this particular design, one grid is positively charged while the other is negatively charged or grounded. This charge differential creates an electrostatic field between the grids, which effectively ionizes particles in the air as they pass through the filter.

When air containing dust, pollen, smoke, and other pollutants flows through the filter, these airborne particles become charged as they interact with the ionized fields of the grids. The charged particles are then attracted to the oppositely charged grid, where they are collected and held, preventing them from recirculating back into the environment. This method not only enhances the efficiency of the air filtration process but also allows for a significant reduction in pressure drop across the filter, making it an effective component in many HVAC systems.

In contrast, if both grids were positively charged, as mentioned in another option, there wouldn't be any attraction of particles since like charges repel each other. Similarly, both negatively charged grids would create a similar situation, preventing the effective capture of particles. If no charge were applied at all, the filter would function poorly, as there would be no mechanism to charge and attract particles, significantly reducing its efficacy. Thus, the correct