The exprimenters put chemicals in sealed plexiglass containers with different plants to produce a list of the top pollution removers. The results are very encouraging. However, once you get them, you can breed them like rats and sell them. Davis Nursery on 5th street between L and Poleline. Also, if you kill plants by over or underwatering them like I do, you should get a Moisture Meter.
Plants are probably cheaper and more effective at removing pollution than any known air filters.
Some air filters actually cause more problems than they solve because they produce ozone which is dangerous. HEPA filters don't produce ozone, but the filter fills up with gunk and that stuff keeps growing. The filter can become a dangerous breeding ground for microorganisms. The article is a great place to learn about the dangers of common air pollutants. In addition, it is used in printing inks, paints, lacquers, varnishes, and adhesives.