In the 1970s, the search for energy efficiency led to build more hermetic buildings, reducing ventilation and fresh air exchange. While this helped save energy, it also caused a significant increase in interior pollutants. The occupants of these buildings began to experience a variety of health problems, such as eye and skin irritation, headaches, fatigue and respiratory symptoms, a phenomenon known as the “Sick of the Sick Building”.
The synthetic materials used in modern construction and furniture emit hundreds of Volatile Organic Compounds (COVS). Even in low concentrations, these chemicals and their reactive by -products can negatively affect health. Given this challenge, and looking for solutions for closed environments of future space stations, the NASAin collaboration with the Associated Landscape Contractors of America (ALCA)explored a natural and economical solution, as they collect in their study.
Plants as natural purifiers
NASA’s research focused on the use of Interior plants and the microorganisms associated with its soil as a life support system to purify air. They evaluated leaves, roots and soil to reduce common pollutants. This idea is based on the fundamental dependence of the human being of plants and microorganisms in the terrestrial ecosystem.
The study tested the capacity of various plants to eliminate three common volatile organic pollutants: benzene, tricloroetileno (TCE) y formaldehyde. The benzene, present in gasoline, inks and plastics, has been associated with blood problems and cancer. The TCE, a key industrial solvent, is used in dry cleaning and is considered a powerful liver carcinogen. The formaldehyde, found in isolates, paper and fume products, irritates the airways and it is suspected that causes throat cancer.
How do plants work? The paper of the soil
The initial tests, carried out in sealed cameras with high chemical concentrations (15-20 ppm), identified several promising plants. However, surprisingly high elimination rates led to investigating the exact mechanism. It was discovered that the floor of the pot and its associated microorganisms They play a more significant role of what was initially thought about the elimination of pollutants.
Experiments comparing plants with complete foliage, soil without foliage and ground covered with gravel revealed that the area of The root and floor It is the most effective area for the elimination of COVs, provided there is enough contact between air and floor. Soil microorganisms, such as species of Bacillus, Pseudomonas and Flavobacterium, are able to biodegrade toxic chemicals. In addition, continuous exposure to these chemicals can increase the capacity of plants and soil to clean the air, since microorganisms can adapt genetically and use pollutants as a source of food.
The most effective plants according to NASA
Although many plants showed some capacity to eliminate pollutants, the results of the tests with low concentrations (more representative of the typical inner air) identified some as particularly efficient. According to the data presented:
● The English ivy (Hedera helix) demonstrated a notable capacity to eliminate benzene (89.8% in 24h), although it was less effective with TCE (10.9%).
● The Sansevieria or mother -in -law (Sansevieria Lawrence) eliminated 52.6% of benzene and 13.4% of the TCE in 24 hours.
● The Dracaena ‘Janet Craig’ It showed good elimination of benzene (77.6%) and TCE (17.5%).
● The Marginata (Dracaena marginata) It was effective for both benzene (79.0%) and for TCE (13.2%).
● The Poto dorado (Scindapsus aureus) eliminated 73.2% of benzene in 24 hours.
● The Moses cradle or lily of peace (Spamphyllum “Mauna”) eliminated 79.5% of benzene and 23.0% of the TCE.
● The Gerbera Daisy (Gerbera Jamesonii) and the I can mum (Chrysanthemum morifolium) They also showed good capacity in tests with high concentrations.
For formaldehyde:
● The Mother -in -law eliminated 31,294 micrograms.
● The Bamboo palm (Chamaedorea seifritzii) eliminated 76,707 micrograms.
● The Dracaena ‘Janet Craig’ eliminated 48,880 micrograms.
● The Marginata eliminated 20,469 micrograms.
● The Moses cradle eliminated 16,167 micrograms.
It is important to note that elimination efficiency can vary according to the initial concentration of the pollutant and the relationship between the volume of air and the plant/soil.
Beyond the pot: the advanced filtering system
Based on these findings, the researchers developed an air filtering system that combines plants with a activated carbon filter and a fan. This design allows to move large volumes of contaminated air through the coal filter, which adsorbs chemicals. Subsequently, the roots of the plants and their associated microorganisms decompose these adsorbed pollutants, “bioregenerating” coal and turning chemicals into plant tissue. This system is considered promising to handle high concentrations of pollutants, such as cigarette smoke or organic solvents.
In summary, this NASA study underlines the significant potential of indoor plants, particularly through the microbial activity on their ground, for mitigate air pollution inside. Incorporating these plants in our spaces not only adds beauty, but also represents a promising and economical strategy to improve air quality and combat the sick building syndrome. The optimization of the contact between the air and the area of the root-soil is key to maximizing its purifying benefits.
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