Plug-in Ionizers and Negative Ion Emitters

IonizerNegative ions are molecules that have been charged with an extra electron. This is done with a high voltage needle. When the molecule encounters another element it tends to give up its extra electron. When the encountered (now charged) molecule comes within proximity to an electrically grounded structure like your wall it sticks via the extra charge.

The bottom line is that they are moderately effective as air cleaners but they take the dirt out of the air and put it on the walls of the environment.