Filter Purifiers

• Filter air purifiers work by using a fan to force air through tiny holes in their filters. More efficient filters have smaller holes and produce cleaner output air, but are also more expensive. The filters gradually fill with particles and need to be changed, but it is difficult to tell when they are full, and the time they last will vary depending on your home's air quality and the amount you run the purifier.
  
  

Ionic Purifiers

• Ionic air purifiers work by emitting a stream of negatively charged molecules, called ions. When the negative ions float into particles in the air, they transfer some of their charge, which makes the pollutant particle weakly attracted to other surfaces. Because of this attraction, the particles stick to surfaces in your home and are removed from the air.
  
  

Considerations

• Ionic purifiers are more expensive but do not require constant filter changes. Filter purifiers have a built-in fan, while ionic machines rely on natural air currents.