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Plants can reduce formaldehyde levels, contained in building materials

The toxic gas formaldehyde can create "multiple chemical sensitivity" and "sick building syndrome", medical conditions with symptoms such as allergies, asthma, and headaches.

A study led by Kwang Jin Kim of Korea's National Horticultural Research Institute compared the absorption rate of two types of houseplants. The results of the experiment on Weeping Fig (Ficus benjamina) and Fatsia japonica, an evergreen shrub.

The results showed the combined total of aerial-only and roots-only portions was similar to the amount removed by whole plants. Complete plants removed approximately 80% of the formaldehyde within 4 hours. Control chambers pumped with the same amount of formaldehyde, but not containing any plant parts, decreased by 7.3% during the day and 6.9% overnight within 5 hours. As the length of exposure increased, the amount of absorption decreased, which appeared to be due to the reduced concentration of the gas.

Aerial parts of reduced more formaldehyde during the day than at night. This suggests the role played by stomata, tiny slits on the surface of the leaves that are only open during the day. The portion of formaldehyde that was reduced during the night was most likely absorbed through a thin film on the plant's surface known as the cuticle. Root zones of ficus removed similar amounts between night and day. However, japonica root zones removed more formaldehyde at night.

by S. C.
21 february 2009, Food & Fun > Nature