So basically, from the article, air purifiers which work ionically barely generate any ozone. If you believed every last scaremongering tactic, you would have to stop drinking cans or bottles containing benzoic acid (sodium benzoate) due to "high levels" of benzene, which add up to less than a second of filling up a car with petrol.
If you wanted to go down the ionic route, I wouldn't let the ozone problem put you off.