US Patent 7402194 - Air filtration using CNT ionization

http://www.freepatentsonline.com/7402194.html

This patent from IBM teaches a small scale and low energy air purifying filter formed using carbon nanotube as an ionization source. Claim 1 reads:

1. A method of electrostatically precipitating airborne particulates, said method comprising:

positioning a first electrode and a second electrode in a housing unit at a distance from one another, said first and second electrodes comprising poles of an electrostatic field;

growing at least one carbon nanotube on the second electrode, wherein said at least one carbon nanotube ionizes gas in said housing unit; and

applying an electrostatic field between said first and said second electrodes.