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Photosynthesis is the biological term for how plants make the energy to grow. It means making something (synthesis) from light (photo). Plants take in carbon dioxide (CO2) from the air through small holes in their leaves. They get water from the soil through their roots. Water plus CO2 plus light equals energy. In making the energy, oxygen is produced that goes back out through the leaf holes into the air you breathe.
Benefits of Indoor Plants
Humans need oxygen to breathe. Plants need CO2. Although CO2 can be toxic to humans, it is like oxygen for plants. Humans give plants CO2 and plants give humans oxygen, which is a mutually beneficial, called a symbiotic relationship.
You probably don’t need more oxygen in your house, and house air does not have enough CO2 to be dangerous, unless there is another source of CO2 like a space heater. But, house plants have another more important function that you can benefit from. They are a low-cost air purification system. Several studies show that indoor plants enhance air quality.
Phytoremediation: How House Plants Clean the Air
The process of plants filtering the air is called phytoremediation. Studies show that when house plants take in CO2 from the air, they also remove indoor VOCs. Air pollution can occur in your house and it can cause lots of problems, like allergies, headaches, infections, and asthma attacks. VOCs can come from smoking, paints, adhesives, plastics, cleaning solutions, and a whole host of other indoor products. Indoor air pollution can be worse than outdoor pollution if you live in a tightly made, modern house, especially since most people spend most of their time indoors.
Phytoremediation can remove cancer-causing VOCs like benzene, trichlorethylenes, formaldehyde, and toluene. It can also remove particulate matter like indoor allergens. Other organic compounds that can be harmful and can be removed by plants include nitrates, sulfates, ammonia, and ozone. Plants can remove airborne microbes like fungi and bacteria. One study found that plants could reduce airborne microbes by 50 percent. Finally, since plants keep indoor humidity at 40 to 60 percent, they can reduce the transmission of airborne viral droplets like flu or COVID-19. These viruses survive in the air and travel farther in low humidity.
How Many Plants Do You Need to Improve Air Quality?
The National Aeronautics and Space Agency (NASA) has been studying indoor plants as a natural filtration system and source of oxygen for space travel and indoor space stations. According to NASA’s research, 15 or more house plants would significantly improve air quality in a living space of 1,800 square feet. The best plants for air quality have lots of leaves, have at least an 8-inch diameter, and grow quickly.
Best House Plants for Oxygen and Air Quality
All plants add oxygen and improve air quality, but some have been studied and found to be best. The highest oxygen producing plants with the highest ability to filter the air include:
- Peace Lily
- Aloe Vera
- Weeping fig
- Areca Palm
- Gerbera daisy
Snake Plant: Oxygen at Night
One of the plants that NASA found beneficial as part of its clean air study is the snake plant, also called mother-in-law’s tongue. Out of five VOCs tested, this plant removed four. Another benefit for NASA is that this plant does not need direct sunlight and it gives off oxygen at night.
Before you load up on house plants make sure they are safe if you have small children or pets. For example, you might want to avoid the snake plant. If children eat parts of this plant, it can cause mild nausea and temporary mouth numbness. Poisoning is more severe in cats and dogs. It can cause severe vomiting and diarrhea in these animals.