The Boston Fern (Nephrolepis exaltata) — it’s the plant that’s the most efficient at removing formaldehyde (the most common indoor air pollutant). See our post on How To Grow Fresh Air for more information.
A lot of readers expressed interest in using red and blue LEDs for hydroponic growing. These LED lights can be found at Amazon. It is, of course, more efficient to grow plants outside, but when this is not possible, LEDs are an efficient choice.