From our perspective as plants, the process you call "air purification" is simply a fundamental part of our existence. We engage in two primary processes: respiration and photosynthesis. During the day, we absorb carbon dioxide (CO2) and light energy to create sugars for food, releasing life-sustaining oxygen (O2) as a byproduct. At night, we respire, much like you do, taking in oxygen and releasing carbon dioxide. This constant gas exchange is our first contribution to improving your indoor atmosphere.
Furthermore, we absorb gases through tiny pores on our leaves called stomata and through our root systems. As we pull water up from our soil and release it into the air through transpiration (a process like sweating), we create a slight pressure gradient at our roots. This helps pull surrounding air, and any volatile organic compounds (VOCs) dissolved in it, down into the root zone where associated microbes can begin to break them down.
Your home is filled with invisible chemicals off-gassing from paints, furniture, cleaning products, and plastics. These are known as volatile organic compounds (VOCs), such as formaldehyde, benzene, and trichloroethylene. To you, they are pollutants. To us, they are a potential food source. The NASA study you reference was significant because it identified specific plant species, including the Peace Lily (Spathiphyllum), that are particularly adept at metabolizing these compounds.
We don't simply "trap" these gases; we biologically break them down. We absorb the VOC molecules through our leaves and roots. Once inside our system, we transport them to our root zone. Here, a symbiotic relationship occurs. Naturally occurring microorganisms (bacteria) living in the rhizosphere—the area around our roots—feast on these chemicals. They break the complex VOC molecules into simpler compounds, which we can then use as a source of energy and carbon for our own growth. It is a beautiful, natural recycling system.
So, why was my species, the Peace Lily, highlighted in such a prominent study? We possess several physical and physiological traits that make us exceptional air purifiers. We have broad, relatively large leaves with a high surface area, providing more stomatal pores for gas absorption compared to plants with needle-like or small leaves. Our dark green foliage is also highly efficient at photosynthesis under the lower light conditions typical of a home, meaning our gas-exchange processes remain active even away from direct sunlight.
Perhaps most importantly, we are known for our high transpiration rate. We move a significant amount of water from our roots, through our stems, and out through our leaves. This vigorous activity acts like a natural air pump, actively drawing the surrounding air toward our root system where the VOC-consuming microbes live. This makes us one of the most effective plants for facilitating the biological degradation of airborne toxins.
It is crucial for you to understand that we are not mechanical air filters like the one in your HVAC system. Our ability to purify air is a biological function, integral to our health and vitality. Our effectiveness is dependent on several factors: access to light for energy, adequate water to maintain transpiration, and healthy leaves free of dust so our stomata remain unclogged. The soil and root microbiome must also be healthy to host the necessary bacteria. A stressed, wilted, or dying Peace Lily cannot perform this function efficiently. You must care for us to enable us to care for you.
