For those that need to know every detail you can, here is a link to some "how it works" info on a Sharp Electronics web site, makers of the Plasmacluster filter technology.

http://www.sharp.ca/products/ion/index.asp

I've heard a lot of bad things about some ion filters, how they create too much ozone to be healthy and actually pollute the air. I haven't heard boo one way or the other on this technology. The web site kind of makes sense if you buy into it. I imagine Toyota would have taken the time to ensure the tech is good before licensing it from Sharp.