Exposure to low levels can cause drowsiness and headaches. Researchers have identified several varieties of houseplants that excel in removing these chemical pollutants from the air. The most effective in removing formaldehyde were philodendron, spider plant, and golden pothos. The peace lily and the chrysanthemum removed the highest percentage of trichoroethylene. Since all plants utilize carbon in the process of producing new growth, all these varieties are effective in removing low levels of carbon monoxide.
All plants produce oxygen through the process of photosynthesis.
Thus any plants you choose, in addition to the varieties named here, will increase the concentration of oxygen in their immediate surroundings. In general, one large plant per 100 square feet of space is sufficient to clean the air in an average home or office. A more heavily polluted environment would require a greater concentration of plants. Most of these houseplants are relatively easy to grow in moderate to bright indirect sunlight or under florescent lighting. Avoid windows or glass doors where sunlight shines directly on the plants, except for flowering mums and gerbera daisy, which thrive in sunlight.