Researcher Kamal Meattle lives in New Delhi -- and breathing the air landed him in the doctor's office with diminished lung capacity. He embarked on research to find a way to clean the air around him using houseplants (much of this work had already been done by NASA and the folks at Biosphere 2). In this four-minute talk, Meattle shares the very simple results -- using just three species of common houseplants, you can create measurably cleaner indoor air, increase oxygen levels, and decrease indoor air pollution. It does take some work (and a lot of plants -- a single person requires more than ten large houseplants!), but ultimately this is a simple recipe for cleaning your indoor air.
In case it goes by too quickly, I've typed up the basics of Meattle's recommendations here:
"The Living Room Plant"Areca Palm (Dypsis lutescens) The workhouse of Meattle's plan. Get four of these per person, and wipe the leaves regularly to clean off crud. Needs occasional time outdoors. "The Bedroom Plant"Mother-in-law's Tongue (Sansevieria trifasciata) Works at night, so put them in the bedroom. You need six to eight per person. "The Specialist Plant"Money Plant (Epipremnum aureum) Filters out formaldehyde and other nasty stuff.
See also: Wikipedia's list of air-filtering soil and plants.