The Pothos, scientifically known as Epipremnum aureum, is one of the most popular and resilient houseplants cultivated across the globe. Its distinctive heart-shaped, variegated leaves and cascading growth habit make it a common fixture in homes and offices. This plant has long been championed as a natural solution for improving indoor air quality, a widespread belief that has driven its popularity. This reputation stems from landmark scientific research, but the practical effectiveness of a single potted plant is a matter of scale. Understanding the scientific basis requires examining the laboratory conditions under which it was first studied.
The Scientific Foundation for Air Purification
The concept of houseplants actively removing pollutants originated with the 1989 NASA Clean Air Study, a research project designed to find ways to purify the air within sealed space habitats. Researchers placed various common houseplants, including the Pothos, into small, airtight plexiglass chambers. They then injected concentrated levels of specific airborne chemicals, known as Volatile Organic Compounds (VOCs), into these sealed environments.
The study focused on VOCs commonly found in modern building materials, furniture, and household products. These included formaldehyde, benzene, and trichloroethylene, which are present in paints, solvents, and synthetic materials. The experiments demonstrated that Pothos and other plants were highly effective at reducing the concentration of these toxic compounds within the controlled, closed system. Within a day, up to 70% of the pollutants were removed by the plant systems. This early research established the biological capacity of plants to metabolize harmful organic molecules.
How Pothos Plants Process Air Toxins
The mechanism by which the Pothos plant system removes airborne toxins involves a dual biological process. One method is the direct absorption of gaseous molecules through the leaves’ stomata, the tiny pores used for gas exchange during photosynthesis. Once inside the plant tissue, enzymes transform the toxic VOCs into less harmful compounds through a process called phytodegradation.
The second, and more significant, method involves the dense community of microorganisms living in the potting soil. Airborne VOCs are transported into the soil as the plant draws air down around its roots or as the compounds passively settle. The roots exude organic compounds that nourish a complex ecosystem of bacteria and fungi, known as the rhizosphere. These soil microbes metabolize the airborne toxins as a food source, continuously breaking them down.
Real-World Limitations on Air Cleaning
While the Pothos plant demonstrates a real ability to clean air in a laboratory, the results do not translate effectively to the average home environment. The original NASA experiments were conducted in small, sealed chambers with minimal air movement, creating conditions that maximized the plant’s metabolic rate against a finite amount of pollution.
A typical home or office, by contrast, is a large, unsealed space with a continuous air exchange rate (ACH) due to open windows, drafts, or HVAC systems. This constant air exchange dilutes the concentration of VOCs much faster than a single houseplant can absorb them. To match the purification rate of typical home ventilation, the required density of Pothos plants becomes impractical for residential living.
Research suggests that one would need between 10 and 1,000 potted plants per square meter of floor space to achieve a noticeable air cleaning effect. For a standard 1,500 square foot home, this would necessitate approximately 680 plants, a density that would interfere with the room’s functionality and purpose. The practical air-cleaning contribution of a few Pothos plants in a modern home is considered negligible compared to mechanical filtration or simply opening a window.