> At least some of the expensive filters have activated charcoal Activated carbon is effective just to remove odors and nothing more. It's not expensive either

> At least some of the expensive filters have activated charcoal Activated carbon is effective just to remove odors and nothing more. It's not expensive either, it's like $ 10/kg retail. A high-end filter is more likely to work with ionization. [1] [1] http://www.amazon.com/Sharp-FPA80UW-Plasmacluster-Purifier-Filter/dp/B0067X12EW/ref=cm_cr_pr_product_top http://www.amazon.com/Sharp-FPA80UW-Plasmacluster-Purifier-F...