Indoor air quality has become a growing concern as modern construction practices create more tightly sealed homes and offices. These enclosed environments can trap volatile organic compounds (VOCs) and other pollutants released from common household items, potentially affecting health. Nature offers a natural method to counteract indoor pollution using specific houseplants. This review identifies which plants are most effective at filtering the air and explains the science behind their purification capabilities.
The Science Behind Plant Air Filtration
Plants absorb carbon dioxide and release oxygen through photosynthesis, but their air-cleaning ability extends far beyond this simple gas exchange. The process by which plants and their associated microorganisms remove gaseous pollutants is broadly termed phytoremediation. This biological mechanism involves both the plant’s leaf structure and the activity within the soil.
The leaves of the plant contain tiny pores called stomata, which are the primary entry points for atmospheric gases. While the plant uses these pores for respiration, gaseous pollutants like VOCs can also be absorbed through this mechanism. The pollutants are then transported down into the plant tissues.
The most significant part of the air purification process, however, occurs not in the leaves, but in the soil and root system. The root zone is home to a dense and diverse community of microorganisms, including bacteria and fungi. These microbes break down the absorbed toxins, converting the harmful organic chemicals into less harmful substances like new plant tissue, carbon dioxide, or water.
The foundational understanding of this capability was established by research conducted in the late 1980s. Initial experiments demonstrated that certain common indoor plants could remove specific volatile organic pollutants from sealed test chambers. The plant-soil-microbe system functions as a living biological filter, laying the groundwork for further investigation.
Top Plants for Indoor Air Quality
Specific plants absorb and break down common volatile organic compounds (VOCs) found in homes, such as formaldehyde, benzene, trichloroethylene, and xylene. Formaldehyde off-gasses from furniture and adhesives; benzene and trichloroethylene are found in plastics, synthetic fibers, and cleaning products. Xylene is an ingredient in paints and varnishes.
The Snake Plant (Sansevieria trifasciata) is highly effective at removing formaldehyde, benzene, trichloroethylene, and xylene. This plant is unique because it uses a specialized form of photosynthesis, allowing it to primarily exchange gases at night. This nocturnal gas exchange makes it a popular choice for bedrooms, as it can absorb carbon dioxide and release oxygen while people sleep.
The Peace Lily (Spathiphyllum) is recognized for its broad-spectrum cleaning ability, targeting formaldehyde, benzene, and trichloroethylene, in addition to ammonia, a common ingredient in household cleaners. This plant is known for its glossy green leaves and distinctive white flowers, and it also contributes to increased humidity in the air.
Dracaena varieties, such as the Red-Edged Dracaena (Dracaena marginata), are proficient at filtering xylene, trichloroethylene, formaldehyde, and benzene. This makes them a versatile choice for areas with new carpets or furniture.
The Spider Plant (Chlorophytum comosum) is one of the most common and easy-to-grow houseplants, and it is particularly effective at reducing formaldehyde and xylene. Studies have demonstrated its ability to remove measurable amounts of formaldehyde, sometimes showing removal efficiencies around 70% in controlled settings.
The Golden Pothos (Epipremnum aureum) is a trailing vine known for its hardiness and ability to thrive in low light conditions. It is a workhorse against formaldehyde and benzene, making it a good choice for garages or areas where vehicle exhaust fumes may enter the home.
The Florist’s Chrysanthemum (Chrysanthemum morifolium) is a flowering plant that excels at filtering benzene, a compound often found in inks, detergents, and plastics. This plant needs bright light to bloom, and while its air-cleaning power is temporary, it provides a powerful burst of purification when used indoors.
Maximizing Air Purification at Home
To effectively use plants for air purification, it is important to understand practical requirements for a noticeable effect in a typical indoor environment. While laboratory studies use hermetically sealed chambers, a normal home has constant air exchange with the outdoors, which dilutes the concentration of toxins. Therefore, a single plant will not purify an entire room.
For a measurable impact on air quality, recommendations often suggest a density of approximately 15 to 18 medium-to-large plants per 100 square feet of floor space. Achieving this high plant density can be impractical for most homeowners, so it is helpful to place plants strategically to maximize their limited purification capacity.
Plants should be positioned near sources of pollution, such as new furniture, freshly painted walls, or computers, to intercept off-gassing toxins directly. Placing plants in areas where people spend the most time, like a home office or bedroom, can also help improve the air quality immediately surrounding the occupants. Avoid placing plants near drafts or vents, as this can stress the plant and reduce its natural air-filtering ability.
Maintaining the health of the plants is also directly linked to their efficiency as air filters. Dust accumulation on the leaves can block the stomata, which are the pores necessary for the plant to absorb air and pollutants. Regularly wiping the leaves with a damp cloth ensures the plant can breathe and photosynthesize efficiently, supporting the overall purification process.
Houseplants should be viewed as a supplement to, rather than a replacement for, proper ventilation and source control. While they contribute to a healthier environment and offer documented psychological benefits, their use should be combined with opening windows or utilizing mechanical air filtration systems for meaningful air quality improvement.