Operation of air filters
Types of residential filters are discussed on the Filters page. This is about how and how well they work. There are two types, mechanical and electronic. Filter media thickness, air speed and particle size are the main factors for how well filters perform in a given situation.

Mechanical filters use three different processes for cleaning. Impaction or impingement, interception and straining. All methods exist in each filter but one method will be predominate.
Impaction is when larger particles can't make the turn around a filter fiber. They fall out of the air stream, impact and stick to a filter fiber.
Interception is a particle following the air stream but still coming in contact with a filter fiber and staying. Filter fiber diameter will effect the size of particle it can most easily capture and hold. Smaller fibers generally do better on smaller particles. Interception is a major factor in electrostatic filters. The generated charge increases the attraction and holding power of the filter media.
Straining is exactly that. The filter fibers are to close together for the particle to fit. Straining has the least effect in the filtering process.

Electronic filters require an outside power source. There are three steps in a good electronic filter installation. The pre filter, ionizing wires and collection plates.
Pre filters are used to filter out the larger particles that may be moving to fast for proper collection. They may also cause "arcing". This makes noise and can generate ozone (O3). Some manufacturers included washable metal pre filters. Disposable spun fiber or pleated filters may be used if the system pressures allow.
Ionizing has a electrified wire in the air stream to place a positive charge into passing particles. Air speed, wire spacing and voltage are the main variables. Voltage usually does not exceed 12kV because of ozone creation.
Collector plates are flat metal strips with a negative charge. The voltage is less the 6kV. Positive charged particles are drawn out of the air stream and stick to the plates. Smooth air flow is essential for small particle collection. Small particles may have a adequate charge but buffeting in the air stream can keep them away from the plates. Positive charged particles that miss the negative collector plates will stick to anything with a sufficient negative charge.