Air purifiers should be approached very carefully. They are typically Ozone generators of some sort. I have done a modest amount of research on them and the results are disappointing. The only positive information on them is by, or paid for by the people that make them. Any independent information on ozone I found is negative. The list citations I have are quite long but can be provided if emailed separately. Ozone is not what the device manufactures claim it to be. This following quote is indicative of the problem: "However, independent studies have shown that ozone generator do not effectively destroy microbes, remove odor sources, or reduce indoor pollutants enough to provide any health benefits. More alarming these devices can generate excessive levels of ozone and may contribute to eye and nose irritation or other respiratory health problems for users." This came from the state of California Health and welfare agency. I can provide a list of none California based citations also. Bruce and Critter [Posted in FML issue 2863]