From a botanical perspective, the Snake Plant (genus Sansevieria, now reclassified as Dracaena) engages in fundamental processes that inherently interact with its aerial environment. Like all plants, it performs photosynthesis. During daylight hours, it absorbs carbon dioxide (CO2) from the air and, using light energy, converts it into oxygen (O2), which is released back into the atmosphere. This process directly increases oxygen levels in its immediate vicinity. Furthermore, through transpiration, the plant releases water vapor into the air, which can modestly increase humidity. These core functions form the baseline of its air-quality interaction, but the story of purification is more specific and hinges on a remarkable adaptation.
The Snake Plant possesses a significant physiological edge in air purification due to its Crassulacean Acid Metabolism (CAM). Most plants open their stomata (pores on the leaf surface) during the day to take in CO2 for photosynthesis, simultaneously releasing water vapor. However, CAM plants like the Snake Plant have adapted to open their stomata at night to minimize water loss in arid conditions. This means they are actively absorbing CO2 and other gaseous compounds from the air during the nighttime hours. Consequently, the Snake Plant is one of the few plants that continues to convert CO2 to oxygen even after the sun has set, making it particularly valuable for improving air quality in a bedroom while people sleep.
The air purification claim primarily stems from a famous NASA Clean Air Study published in 1989. The study found that Snake Plants, along with several other houseplants, were effective at removing certain volatile organic compounds (VOCs) from a sealed experimental chamber. The plant's leaves absorb toxins such as benzene, formaldehyde, trichloroethylene, xylene, and toluene through their stomata during gas exchange. Once inside the leaf, these compounds are broken down and neutralized through metabolic processes within the plant's cells or are translocated to the root zone. There, they are broken down by microbes present in the soil ecosystem surrounding the roots. This entire system—plant and soil microbiome—acts as a biological filtration unit.
It is crucial to contextualize the plant's ability from a practical standpoint. The NASA study demonstrated efficacy, but it was conducted in a highly controlled, sealed laboratory environment. A typical home or office has constant air exchange with the outside environment through doors, windows, and ventilation systems. Therefore, while a single Snake Plant does actively and verifiably remove trace amounts of toxins from the air immediately surrounding it, one cannot expect a single plant to purify the entire air volume of a large room. The real-world effect is more subtle and contributory rather than comprehensive. To meaningfully impact indoor air quality, a significant number of plants would be required, effectively creating a "bio-wall" or large grouping to process a greater volume of air.
