US Patent 7147692 - Nanoparticles for Air Cleaning

http://www.freepatentsonline.com/7147692.pdf

There has been discussion in some circles about possible adverse environmental effects of nanoparticulate matter. However, this patent from Procter & Gamble looks to the high surface to volume ratio characteristics of nanoparticles to assist in air purification. Claim 1 reads:

1. A method for cleaning indoor air comprising contacting the air with an aqueous or non-aqueous liquid through a packed column scrubber comprising a photobleaching agent with nanoparticles dispersed therein in a stand-alone apparatus.