The most efficient air filter for improving air quality is the electronic air cleaner. Air returning to the furnace or air handler passes through a screen to trap any large dust particles or objects. The dust particles pick up a positive charge, then pass through plates or grids that are negatively charged. Opposites attract, and the dust particles collect on the plates. Smoke is microscopic particles, and is trapped as well.
Ozone is created from the charged air, which helps kill bacteria and odors.
The dirtier they get, the lower the effectiveness, so clean grids are a must. Before removing the screens and grids for cleaning, it is imperative to shut the power off and wait a few seconds to allow the grids to lose the static charge. They are dishwasher safe as long as they fit inside. If not, sloshing around in a tub of hot soapy water will loosen dirt that can be blasted off with a garden hose. Extreme caution must be taken when handling to protect the grids and the person handling them.