If you are looking for an air purifier, the term filterless (the most well known being the Ionic Breeze) will pop up now and then. They work by charging the incoming air, moving it across a collection point with an opposite charge, with the result of dust and impurities in the air glomming on to that collection grid. The grid will have to be cleaned, quite often if there are smokers around.
A byproduct of this process is ozone, deemed by some as a health hazard and a potential irritant to people with respiratory problems. So be careful to keep the size of the room within the limits on the air purifierís manual.
Filterless air purifiers eliminate expensive filters but the initial investment can be costly. They are almost noiseless, unlike other types of purifiers, so you can run it while you are sleeping.
If expensive filters and noisy operation are a real turnoff, check out a filterless air purifier.