Plants have a reputation for being able depollute the ambient air of the house, and this is part of the growing craze for different plant species to grow indoors. Moreover, whether or not they are depolluting, plants are absolutely essential and it is not just a question of aesthetics, far from it, sincethey improve our living environment. But are they really depolluting? To find out, let’s take a look at the conclusions published by scientists who have looked seriously at the issue thanks to the Phyt’air program to find out whether or not the degradation of organic compounds was possible by plantsthat is to say the phytoremédiation.
Main pollutants at home
We can say that the quality of indoor air is far from healthy because pollutants are very numerous. For example, you can find there:
- Dioxides of carbon, sulfur, nitrogen,
- carbon monoxide,
- You radon,
- allergens,
- Bacteria…
Cigarette smoke, combustion vapor, building materials, glues, lead paint, dust, solvents, insecticides are among the many sources of pollutants present in our homes and business premises.
Why do we say that plants are depolluting?
It was in the mid-1970s that the NASA entrusted major work to its principal investigator, Bill Wolverton. The objective was to identify the plants capable of purifying the air to which the astronauts confined in shuttles and the like were exposed. No less than fifty plants were therefore tested and recognized as more or less depolluting. These results were confirmed in the 1990s by researchers around the world.
According to Bill Wolverton and later scientists, it was therefore possible to purify indoor air with plants. For your information, the plants have been classified by Bill Wolverton as part of the Biohome project according to their ability to purify the air by absorbing various pollutants.
Depolluting plants: what are scientists saying today?
More recent studies have been carried out by scientists to study the depolluting capacities of plants. A vast subject which has not yet finished being elucidated since other studies are in progress. However, according to the findings of French program Phyt’airit appears that it is exclusively under very specific conditionsto know in laboratorythat plants have the ability to make the surrounding air healthier.
What is the Phyt’air program?
The Phyt’air program ran from 2001 to 2012. The long-term work that was carried out had a specific objective: to work towards improving air quality inside enclosed spaces. This program took place in three steps quite distinct.
La phase Phyt’air I
It has enabled researchers to scientifically measure the depolluting capacity of various plant species.
La phase Phyt’air II
It was devoted to the deepening of studies carried out both on plants and on pollutants in order to glimpse the different possibilities of cleaning the air by plantsand more precisely thanks to soil/plant systems since it appears that the efficiency of the substrate, micro-organisms and roots is higher than that of the foliage in terms of absorption of pollutants.
La phase Phyt’air III
It made it possible to perform a indoor biomonitoring workand to do this, the experiments carried out during the previous phases were transferred in real conditions (schools, administrative offices, farms). At the end of this third phase of the Phyt’air program, it was concluded that outside of a laboratory, the action of plants in such conditions did not make it possible to obtain a sufficient purification efficiency.
During the Phyt’air program, more than three hundred plant exhibitions were carried out under various conditions. A significant difference was noted between the results obtained after the exposure of the plants in realistic conditions and those observed previously in the laboratory where the conditions were extremely controlled, and consequently incommensurate with the interior of a house, an educational establishment or other.
The actual absorptive capacities of potted plants
Three plants frequently grown indoors were used during the Phyt’air program, namely:
- The Dragonnier (Dracaena marginata),
- The Phalangere (Chlorophytum comosum) also commonly known as spider plant,
- The devil’s ivy (Scindapsus aureus).
But many other studies have been carried out around the world using dozens of different species of potted plants to verify their “depollution” capacity, such as:
- The date palm,
- The Gerbera,
- Mother-in-Law’s Tongue,
- The Kentia,
- Le Ficus benjamina,
- Le Ficus elastica
- Moon Flower,
- Ferns…
It would be an exaggeration to claim that plants are not depolluting at all. But it’s more accurate to say thatthey have an effective absorption capacity in a controlled environment. This capacity is also variable depending on the pollutants but also on the plants. In real living conditionsthe elimination of pollutants is however not not significant enough to claim that plants can purify our indoor environments. It is nevertheless accepted that they participate in the improvement of our living environment, but ventilate a room optimally is one of the active strategies to limit the presence of pollutants, as recommended by ADEME.