2023-07-25 11:24:59
image copyrightGetty Images
image caption,
Plants decorate the house, but do they purify the air?
Article informationAuthor, Christine RoRole, BBC Business Technology Reporter
15 minutes ago
Most people don’t realize how many pollutants circulate indoors, where they spend most of their time.
For example, many of the products we use to clean and scent our homes, schools, and workplaces add invisible toxins to the air.
“The smell of freshness is not a smell,” says Anne Hicks, a pediatric pulmonologist at the University of Alberta.
“If you can smell it, there’s a chemical in the air that gets into your nose. So it’s air pollution, whether the smell is good or bad,” she adds.
“Indoor air pollution is huge and it’s a relatively unknown frontier because even my neighbor’s house isn’t polluted in the same way mine is,” says Ms Hicks.
We recommend
Indoor air pollution is very complex, poorly regulated and often beyond individual control. For example, road traffic produces nitrogen dioxide, while dampness and structural problems in buildings can lead to mold.
Air purifiers with HEPA (High Efficiency Particulate Arrestance) filters can be helpful. But the initial cost and energy required to run them may be out of reach for many households.
This is one of the reasons why it is so attractive to consider potted plants as an inexpensive and passive air purifier. Plant leaves absorb carbon dioxide and other pollutants, which are either used in various plant processes or broken down.
The community of microorganisms and the growing medium (such as soil or compost) are particularly important in this respect: according to numerous studies, they absorb pollutants more than the plant itself.
An important NASA study from 1989 showed that plants located inside buildings can remove formaldehyde and other volatile organic compounds (VOCs) from the air. But the study was not carried out under realistic, ordinary and real conditions.
In fact, it would take an indoor forest to significantly reduce VOCs in a home.
“It takes a lot of plants in a very well-lit space to have a measurable impact on removing VOCs and many other gases,” says Tijana Blanusa, senior horticultural scientist at the Royal Horticultural Society and researcher at the University of Reading (UK).
Similarly, for carbon dioxide, “it takes a very large number of plants to achieve measurable effects at the ambient scale.”
So is increasing the number of plants the solution?
photo credit, PAUL DE BOIS
image caption,
Green walls are expensive to build and require a lot of maintenance
Some researchers, including Tijana Blanusa, have switched to growing active (living) green walls instead of individual plant pots. This model helps to concentrate more plants and filter the air more efficiently thanks to the way it can be moved through them.
“The air in the room is pushed or encouraged by the root systems to a higher level than would occur naturally if the plants were potted,” she explains of the green walls.
However, these walls are expensive to install and maintain. This is why most people continue to experiment with individual plants.
When construction company Cundall moved into its current London premises in 2015, it filled one of the meeting rooms, known as the ‘Green Lab’, with plants.
The aim was to monitor and record the impact of plants on indoor air quality. But it was difficult to take care of all the plants.
It also appeared that plants did not have the same effect on air quality as mechanical ventilation and air purification systems.
The room now has a few large plants in the corners, as well as a small rectangle of reindeer moss kept on the wall. Squishy foam is nice to touch and look at, but it lacks the ability to absorb pollutants.
image caption,
Kavita Kumari says plants in the home have little effect on air quality
When clients ask regarding the ability of plants to improve air quality, Kavita Kumari, Associate Director of Cundall’s London office, is honest and advises them on the benefits and limitations of plants.
She recommends plants that are relatively low-maintenance and at the same time able to reduce some VOCs and produce oxygen, although she acknowledges that these effects are small.
One of these plants is St. George’s sword, which many people already have in their homes. Kumari explains that while most plants take in carbon dioxide and release oxygen during the day, this one also does this process at night.
According to her, it is not enough to open a window to let pollutants out of the house, because in highly urbanized areas, outdoor pollutants can enter at the same time.
Scientists are currently working on a new generation of plants to make them particularly effective in purifying the air through bioengineering.
Researchers at the University of Washington (USA) modified plants of the species Epipremnum aureum, known in Brazil as jiboia or hera-do-diabo, and included in their system a synthetic version of a protein found in rabbits, which can process chloroform and benzene gases.
The Neoplants company has also modified the genes of this plant to enable it to recycle certain VOCs.
Additionally, the company has produced beneficial bacteria that are particularly effective at breaking down VOCs, which are carried to plant root systems. It is this microbiome, rather than the plant itself, that produces most of the air-purifying effects.
However, even multiplying by 30 the results obtained by NASA in its research, as Neoplants claims to do, it would still not be possible to rely exclusively on indoor plants to purify the air.
Photo credit, ANTOINE GUILLOTEAU/NEOPLANT
image caption,
Neoplants has genetically modified certain plants
For now, the actual ability of indoor plants to purify the air is therefore limited and cannot be compared to that of air purifiers.
But plants have other obvious benefits, including on mood, creativity, and productivity.
Ms. Kumari advises her clients to follow the objectives set by the WELL Building Standard, a certification that aims to promote health and well-being in different types of buildings. One of these goals is to cover 1% of the interior surface with plants.
This goal falls under the “mind” category rather than the “air” category, suggesting that there is more evidence of the benefits of plants for mental health than for air quality. As Kumari says, “plants give a sense of calm”.
Ultimately, air quality experts remain supportive of having plants in homes. But don’t expect too much.
1690284797
#plants #purify #air #home
