The Physics of an Air Filter

This is a picture of an air filter in my house that is meant to capture harmful materials in the air such as dust, cotton, and pollen. The filter is able to do this through the use of technology that is related to what we are learning in Physics right now. Near the front of the filter is a grill, which is called the "corona discharge" and is meant to ionize particles in the air. This electrical field gives extra electrons to the neutrally charged particles in the air. Because dust and other harmful substances are usually large, they are the ones who gain the negative charge produced by the "corona discharge." Further into the filter there is a metal plate with a strong positive charge, to which the now charged particles in the air are attracted to. With most of the harmful materials gone, clean air can flow from the top.