Electrical attraction is another technology used by air purifier appliances to trap airborne particles. There are three types of products that use this technology: electrostatic precipitating cleaners, electret filters, and negative ion generators.

Electrostatic precipitating (also called “electronic” air purifiers) draw particles into the unit via a fan and charge them with a series of high-voltage wires. Several plates (the precipitating cells) carry the opposite electrical charge and attract the contaminants as they pass by the plates, thus trapping them. They are typically not as effective as HEPA, removing 95% of airborne particles as opposed to 99.97% in a HEPA air purifier.

Electret filters use synthetic fibers to create static charges to attract particles.

Negative ion generation is a technology that is sometimes used as the sole cleaning agent, or in conjunction with HEPA filtration in an air purifier. Negative ions are emitted into the air and attach to the positively charged particles in the room, then clumping together to settle out of the air onto a surface. Read more about air purifier technology.