The Epipremnum aureum, commonly known as Pothos or Devil’s Ivy, is a popular vining houseplant celebrated for its resilience and ease of care. It is also widely known for its purported ability to purify indoor air. This claim originates from decades-old scientific research suggesting the plant can effectively scrub harmful chemicals from enclosed spaces. This analysis examines the biological mechanism behind this air-cleaning ability and addresses the practical reality of its impact on air quality inside a modern home.
The Mechanism of Plant-Based Air Cleaning
The process by which plants filter atmospheric pollutants is known as phytoremediation. This biological function involves a two-part system to remove Volatile Organic Compounds (VOCs) from the air. Leaves absorb a small portion of these gaseous contaminants through tiny pores on their surface called stomata.
The majority of air purification occurs in the root and soil environment, not within the plant itself. The potting mix contains a complex ecosystem of microorganisms, including bacteria and fungi, that thrive in the root zone. As the plant draws air down through the soil, these microbes consume the VOCs, breaking them down into harmless compounds. This symbiotic relationship between the plant’s roots and the soil microbiome is the main driver of pollutant removal in potted plants.
Pothos and Targeted Air Pollutants
The scientific basis for the Pothos’s air-cleaning reputation originates from the 1989 NASA Clean Air Study. This landmark research explored methods for cleaning the air in sealed environments, such as future space stations, where airborne toxins concentrate. Pothos was one of the plants tested in these controlled laboratory settings.
In this sealed environment, the plant demonstrated an ability to reduce the concentration of several common household VOCs. Pothos was found to target specific compounds: formaldehyde, released from building materials and furnishings; benzene, a solvent found in plastics, fabrics, and pesticides; and xylene and toluene, components of paints, adhesives, and varnishes. These early findings established Pothos as an effective biofilter under the specific conditions of a closed chamber.
Scientific Claims Versus Home Reality
The significant difference between the laboratory environment and a typical dwelling determines the practical impact of a Pothos plant. The original NASA study used small, sealed chambers with no air exchange, measuring the plant’s effect against a high concentration of toxins. A standard home, by contrast, has a constant rate of air exchange (ACH) with the outside environment, which continually dilutes and replaces indoor air.
The air exchange rate in a typical building is far more efficient at removing VOCs than a small number of houseplants. To achieve the same rate of air purification seen in the sealed laboratory studies, an immense density of plants would be required. Current research suggests that making a measurable difference in air quality requires approximately 10 to 1,000 plants per square meter of floor space.
For a large room, this requirement translates into hundreds of plants, effectively turning the space into a greenhouse. While Pothos technically filters the air, its practical contribution to improving indoor air quality in a standard, ventilated home is minimal. Mechanical air filtration systems or simply opening a window are far more effective at reducing pollutant levels.
Pothos Safety Considerations
While Pothos is celebrated for its decorative qualities, the plant contains compounds toxic to both humans and pets if ingested. All parts of the Epipremnum aureum contain insoluble calcium oxalate crystals. These microscopic, needle-shaped structures are released when the plant tissue is chewed or bitten.
Upon contact, these crystals penetrate the delicate tissues of the mouth and throat, causing intense pain and irritation. Symptoms in humans and animals typically include excessive drooling, oral swelling, difficulty swallowing, and vomiting. Although ingestion is rarely fatal, the discomfort is significant, requiring the plant to be placed safely out of reach of curious pets and small children.