Samsung's S-Plasma Ion - scientific basis
if you can take a look at the main web site, then it seems they make $\ce{HO2}$ and not $\ce{HO2-}$. This a peroxy radical which exists at trace levels in the ambient atmosphere, usually from reactions of light with oxides of nitrogen and volatile organic compounds. Its really reactive and I don't know for sure how long it will last in the air of the room. It will however react with $\ce{OH}$ radical and make water and $\ce{O2}$. $\ce{HO2 + OH -&gt; O2 + H2O}$. $\ce{HO2}$ will also react with $\ce{NO}$ to form $\ce{NO2}$ and then depending if there is sunlight could make ozone. One of the issues for the machine will be that $\ce{HO2}$ will need to made at some point and therefore one of the first molecules it will encounter will be itself and therefore make $\ce{H2O2}$ (hydrogen peroxide). I think getting one into a lab and testing it would be a start.