[url=http://en.wikipedia.org/wiki/Air_ioniser#Ionic_air_purifiers]WikiPediA[/url] said:
Consumer Reports court case
Consumer Reports, a non-profit U.S.-based product-testing magazine, reported in October 2003 that air ionisers do not perform to high enough standards compared to conventional HEPA air filters. In response to this report, The Sharper Image, a manufacturer of air ionisers (among other things), sued Consumer's Union (the publishers of Consumer Reports) for product defamation. The Sharper Image's Ionic Breeze unit did meet all EPA guidelines, including less than 50 ppb ozone production [citation needed]. Consumer Reports gave the Ionic Breeze and other popular units a "fail" because they have a low Clean Air Delivery Rate (CADR). CADR measures the amount of air circulated during a short period of time, and was originally designed to rate fan-based purifiers. The Sharper Image claimed that this test was a poor way to rate the Ionic Breeze, since it does not take into account other features, such as 24-hour a day continuous cleaning, ease of maintenance, and silent operation. The U.S. District Court for the Northern District of California subsequently struck The Sharper Image's complaint and dismissed the case, reasoning that The Sharper Image had failed to demonstrate that it could prove any of the statements made by Consumer Reports were false. The Court's final ruling in May 2005 ordered The Sharper Image to pay $525,000 USD for Consumer Union's legal expenses