No, your green plants do not really purify the air inside your home

Indoor plants have the power to brighten up a home, no doubt. However, their "depolluting" effect should be taken with a grain of salt.

There is a tenacious idea that green plants purify the air in a room. Because the impact of the pollution of our interiors is very real. Burning a candle, using a cleaning spray in the kitchen, or putting on perfume, are all additions of particles to the air in your home, which add to the pollution already emitted by paints, fabrics, heating appliances, potential mold, etc.

Without necessarily being fatal, these harmful substances present in the air can be allergenic (pollen, dust mites, dust), cause respiratory diseases or chronic fatigue..

Solutions exist

In truth, to protect yourself from indoor pollution, there is no secret : you must ventilate your home every day. There are also air purifiers with high-efficiency particulate filters (HEPA), which are very effective, but may be financially out of reach for many households. So, faced with this belief that green plants, in addition to brightening up an interior, help to purify it, we would be tempted to buy more and more of them. Except that it would literally take a jungle at home for this to have a real impact on our health.

Indeed, the 1989 NASA study that found that certain houseplants could remove formaldehyde and other volatile organic compounds (VOCs) from the air was seen around the world and had a significant influence. But the study carried out in the laboratory became unrealistic in real conditions.

Concretely, the leaves of plants absorb particles and gases, such as the carbon dioxide that we emit through our breathing, and then use them through various processes specific to these plants, having the effect of decomposing these pollutants to transform them into organic products. The plants then emit water vapor when they transpire, which improves the humidity and oxygen levels of the environment. In fact, the microorganisms present in the soil or compost that form the soil where the roots of the plant grow are particularly important, more so than the plant itself, according to numerous studies.

"Depolluting": a marketing argument

"You need a very large number of plants in a very well-lit space to have a measurable impact on removing VOCs and many other gases," such as carbon dioxide, Tijana Blanusa, a researcher at the University of Reading and the Royal Horticultural Society, told CNN.

The British expert advises instead to set up a green wall that can concentrate more plants indoors to possibly have a real filtering effect. "Room air is pushed and sucked through the root systems at greater levels than would naturally occur if you just had plants in a pot," she adds. A solution that is nevertheless difficult to install and maintain.