NASA scientists have found that houseplants are useful in absorbing potentially harmful gases and cleaning the air inside modern buildings.

The foliage of indoor plants is capable of removing low levels of pollution, while the plant's roots, assisted by activated carbon filters, removed air pollutants at higher concentrations. In tests, these filters removed and biologically degraded pollutants before they accumulate.

Here's NASA's list of the top house plants that were most effective in removing formaldehyde, benzene, trichloroethylene, and carbon monoxide:

Bamboo palm, Chinese evergreen, English ivy, Gerbera daisy, "Janet Craig" Dracaena, Dracaena "Marginata," Corn plant, Mother-in-Law's Tongue, Chrysanthemum, Peace lily and Dracaena "Warneckii."