When we want to give a little life to our homes, the first thing we think about is putting in several plants with the idea that, in addition to giving it a more natural touch, they will also clean the air we breathe. And it’s no wonder, because all you have to do is take a look around the internet or through the hallways of any nursery to find us. with the promise that pothos, mother-in-law’s tongue or ribbon are “natural purifiers” that eliminate toxins. But It’s not like that.
The origin of the idea. To understand why we blindly believe in the purifying power of the plants that we can have in our home, the responsibility lies with NASA and its classic studies published in the 80s. Here, in their quest to find ways to clean the air on space stations, researchers placed different plants in hermetically sealed chambers and injected volatile organic compounds that were partly removed by the plants.
This was very relevant, but the extrapolation to the general population, not so much. And these investigations were carried out in an airtight chamber in a laboratory, and at the moment a home or an office is not hermetically closed, but there is the possibility of air constantly entering and leaving through windows, doors or cracks. But this detail has not resonated so much with the population.
A bath of reality. This arrived in 2019, where a study from Drexel University analyzed a dozen previous studies to evaluate actual plant performance using a standard metric: the clean air delivery rate, or CADR. Here the conclusion reached is that potted plants do not improve indoor air quality in a relevant way.
And the explanation is purely mechanical, since the normal ventilation of any building eliminates volatile organic compounds at a rate faster than the absorption capacity of an indoor plant.
Size matters. With this premise, for the plants to match the purification achieved by the ventilation system of a standard building or the simple act of opening windows, you would need between 10 and 1,000 plants per square meter. I mean, you would have to literally turn your living room into a dense, impassable rainforest to notice the difference.
Very controlled exceptions. This does not mean that all pro-plant studies lie, but rather that context is everything, since some studies point to a decrease in CO₂ levels.
A notable example is a study conducted in a school in Portugal, where flower pots were introduced into classrooms and an improvement in the air was measured. However, the scientists themselves warn that these are highly specific and controlled environments and their results cannot be mathematically extrapolated to what happens in the living room of a normal apartment or in a standard office.
There is no evidence. Given all this that we already know, the authorities are sharp noting that there is no evidence that a reasonable number of indoor plants remove significant amounts of pollutants in homes and offices.
What do we have to do? In order to improve air quality inside the home, the important thing here is to reduce the use of chemicals and avoid smoking indoors. In addition, opening the windows every day to renew the air is the key measure, as well as the installation of air purifiers, which are almost mandatory in many cases for people who have significant allergies.
Images | freepik
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