The Peace Lily (Spathiphyllum) is a widely recognized indoor plant cherished for its glossy, dark green leaves and distinctive white flowers. It is a common fixture in homes and offices, largely due to the pervasive idea that it actively cleans the air. This belief suggests the plant can significantly scrub indoor spaces of harmful chemical compounds. Does the Peace Lily truly possess the air-purifying capabilities it is famous for?
The Origin of the Air-Cleaning Claim
The reputation of the Peace Lily as an air purifier traces its roots back to the 1989 NASA Clean Air Study. This research investigated methods for maintaining air quality in sealed environments, such as future space stations. Scientists placed common houseplants inside small, sealed test chambers and introduced specific airborne pollutants. The Peace Lily was one of the plants that demonstrated an ability to remove these toxic gases.
The key context of this foundational research is the highly controlled nature of the experiment. The plants were confined in an airtight container, and the air exchange rate was negligible. Under these specific, non-ventilated laboratory conditions, the Peace Lily showed measurable pollutant reduction over a 24-hour period. These results provided the initial scientific backing for the air-cleaning claim.
The Science of Removing Indoor Pollutants
The biological process by which the Peace Lily interacts with airborne toxins is called phytoremediation. This mechanism involves the plant taking up and neutralizing pollutants from the surrounding environment. The plant targets volatile organic compounds (VOCs), which are airborne chemicals emitted by everyday household items like paints, furniture, and cleaning products.
Specific VOCs the Peace Lily removes include formaldehyde, benzene, and trichloroethylene. The plant utilizes its leaves, primarily through tiny pores called stomata, to absorb these gaseous compounds. However, the most significant detoxification occurs in the plant’s root system. Microorganisms living in the potting soil and around the roots are responsible for breaking down the absorbed VOCs into harmless byproducts.
Practical Effectiveness in Home Environments
The scientific findings from the sealed chamber studies do not directly translate to a typical residential setting. Real-world rooms feature constant air exchange with the outdoors, which dilutes and removes pollutants at a rate far exceeding the capacity of a single houseplant. Modern buildings generally have a higher rate of air turnover compared to the airtight boxes used in the initial NASA testing.
To achieve an air cleaning rate comparable to standard home ventilation, the quantity of plants required becomes impractical. Estimates suggest that achieving a measurable improvement in air quality would necessitate placing between 10 and 1000 plants per square meter of floor space. This would require an unmanageable density of foliage for a standard-sized room. While a Peace Lily technically removes VOCs, its overall impact on the air quality of a well-ventilated home is minimal compared to mechanical filtration or fresh air exchange.