It was 1989 when a work commissioned by NASA was published that aroused a lot of interest, also because it focused on a problem that would become increasingly important over the years, air pollution in homes and offices. In particular, the author of the study, the scientist B.C. Wolverton, had tried to identify the most effective plants at removing the main pollutants and toxic substances to humans, such as formaldehyde, benzene and toluene, from the air. And Wolverton had succeeded in his goal by publishing a list of just over 50 plant species capable of improving the microclimate of offices and homes. Among these plants there is the Dracaena deremensis Warneckii, also called the trunk of happiness, but let's try to understand better.
Pollution in buildings, possible sources
For external pollution, for the numerous sources of noise but also for energy saving, we live and work indoors where the fresh air exchange is often reduced. The problem is that closed environments are not protected from the release of pollutants. In fact, often the risk is right inside the home and, where there is little air exchange or the outside air is very polluted, toxic substances can accumulate. Formaldehyde is an irritant and classified as a carcinogen by the IARC. Formaldehyde is released in combustion processes, so, for example, it is a product of cigarette smoke. However, this substance is also found in chipboard and plywood, in insulating materials, in resins used for upholstery and carpet, curtains and fabrics subjected to anti-crease treatments (Source Italian Ministry of Health). Benzene is a substance classified as a carcinogen. Benzene is emitted from cigarette smoke, but also from paints, glues and solvents. Not only that, incorrect positioning of the air intakes in the vicinity of underground parking lots, garages and high traffic streets increase the benzene values in closed spaces (Source Italian Ministry of Health). Trichlorethylene is classified as a probable carcinogen and can cause developmental problems such as heart malformations. Trichlorethylene is released by solvents and is released into the atmosphere by industrial metal degreasing processes, it can contaminate both surface water and groundwater (Source Italian Ministry of Health).
Anti-pollution plants, how they work
Anti-pollution plants act by removing toxic substances essentially through two mechanisms. The first is direct and is represented by the absorption and subsequent elimination of pollutants. The second, on the other hand, is indirect and is the result of the transformation of pollutants into new plant tissue by micro-organisms that live on the plant itself and on its soil (Cruz et al, Environ Sci Pollut Res, 2014). Indeed, it has been observed that the soil plays an essential role in the removal of toxins from the environment, as shown by the researches of Wolverton who tested for each plant its anti-pollution action both in case of dense foliage and by removing the lower leaves leaving discovered the soil. In the latter case, the plant was more effective in removing pollutants since more soil was in contact with the environment and therefore freer to act (Wolverton, Interior Landscape Plants for Indoor Air Pollution Abatement, 1989 ).
The beneficial action of Dracaena deremensis Warneckii
Considered the lucky plant par excellence, so much that it is nicknamed the trunk of happiness, Dracaena deremensis Warneckii is a type of evergreen plant, excellent as an ornament in offices and homes. Its shape resembles the palm tree and is characterized by narrow and arched dark green leaves with silver streaks. The plant, in addition to adding a joyful note to the interior, is also beneficial for the microclimate in the house. In fact, the trunk of happiness was able to remove, in 24 hours, 50% of the formaldehyde contained in a room. Not only that, Dracaena Warneckii removed 52% of benzene, although in other measurements it achieved 70% removal of this substance, and 10-20% of trichlorethylene after being placed in a closed room for 24 hours ( Wolverton, Interior Landscape Plants for Indoor Air Pollution Abatement, 1989). And this dracaena is also easy to grow. It loves bright environments but it is better not to expose it to direct light, watering should be such as to guarantee only moist soil and the plant resists up to 10° C, therefore to a temperature that is difficult to reach in a home or office.