The first time I saw a commercial regarding those ion or ozone air purifiers I knew it was a scam. My theory was that a high efficiency filter doesn't mean anything if the air flow is low. The ORECK XL for example may remove 95% of all particles but if the air exchange rate per hour is very low then most of the air in a room is untouched. Well it turns out that it is even worse then I thought. When the manufactures claim their air purifiers clean 95% of airborne contaminants they provide no particle size range. As a matter of fact these purifiers remove mostly large particles while standard HEPA filters meet a minimum efficiency of 99.97% at 0.3 microns. Turns out the majority of harmful particles are 3 microns or less in size as small particles travel deeper into the lungs, causing more damage while larger particles get trapped in your nose a throat. In addition these ion purifiers can release harmful ozone into your home. Consumer Reports criticizes ionic air purifier. I guess the moral is that scientific claims can be used to mislead... do your research.