Sitting in the middle of a forest, you will feel how fresh the air you breathe is. In school, we also learned that plants can absorb carbon dioxide and produce oxygen. These facts make people believe that having houseplants may improve indoor air quality. But is that true?
How Plants Work
The leaves of plants have pores that can absorb gases around them, including some types of air pollutants. With the help of sunlight, plants perform photosynthesis. This process turns carbon dioxide into oxygen, which makes the air feel fresher when we breathe it in.
Pollutants absorbed by the leaves will get filtered out so they will not return to the open air. Meanwhile, at the bottom of your plant pots, the microorganisms that live in the soil play an important role in neutralizing those pollutants.
How Effective Are They?
Although the process makes sense, it turns out that a pot of houseplants can only filter a very small amount of air. Furthermore, the process of absorbing and neutralizing air pollutants is incredibly slow. Because of this, it would be impossible for a houseplant to maintain good indoor air quality on its own.
Compared to an air purifier, the capability of houseplants to remove pollutants from your indoor air is very low. To match the effectiveness of a regular air purifier, you need approximately 10 houseplants per square foot of floor area. That means hundreds of houseplants are required to keep the air clean in one small room.
Different types of plants have different capabilities when it comes to purifying the air. But even with the most effective plant at purifying air, you would need at least one large pot for each square foot. It is clear now. Buying houseplants is not a cheaper alternative to an air purifier.
The Origin of the Myth
The reason why some people believe that houseplants can improve air quality is because of an experiment performed by NASA. Back in the 1980’s, the institution tried keeping houseplants in its space station lab. They concluded that the 19 houseplants they kept significantly improved the indoor air quality in the space station’s lab.
Unfortunately, the conditions in residential buildings are a lot different than those in a space station lab. There are many types of pollutants in a house that are absent in the space lab, such as cooking combustion, dust, dirt, chemical compounds from cleaning agents, and many more. Hence, the indoor air quality in houses or offices is lower than in NASA laboratories. Some research has even found that indoor air can be far more polluted than the outdoor air in big cities.
The benefits of houseplants are mostly psychological rather than physical. They are pleasant to look at, and they can provide a sense of comfort and serenity. Therefore, even if they can’t effectively improve your indoor air quality, having some plants in your house is not a bad idea.