Ionizers have the ability to remove small particles in the form of smoke that is suspended in the air. Ion generators can charge the particles in a room that will make them latch to floorings, curtains, and walls. Ozone generators produce a gas called ozone, which is an irritant for the lungs.    When combined, ionizers and other ozone-generating air cleaners must be used with caution so as to prevent producing high levels of lung irritants that may become detrimental to human health.