Looking For A Small Ionizer And/or Air Purifier?

I am Looking for a small ionizer and/or air purifier to place near my new computer to help clean the air and to help keep particles out of the computer. What would be best to get, an ionizer or air cleaner? I would prefer something small and no filter to clean. I found a couple at walter drake and harriet carter that i like but i'm not sure how well they clean.
Thank you in advance
Jason