Ions are nothing more than atoms or molecules that have gained or lost an electron.
Thses ions, in turn, react wuth dust and pollutants to form larger perticles. Negative ions collide with airborne molecule- which are large raft for hundreds of toxic chemical and diseases organisms. The Negative ion gives up its negative charge to the molecule. These new negative molecules are then attracted to the positive molecules surrounding them. This accumulation process continues until the particles become heavy enough to fall to the floor.