Which plants purify your indoor air best?

Houseplants make an excellent addition to your indoor spaces. Adding a bit of green to your space via indoor plants has a calming effect and brings nature into your home or workplace. Air-purifying plants use phytoremediation, a natural process used by plants to clear the air, soil, and water of pollutants. Some indoor plants, however, purify the air better than others! Which plants purify your indoor air best? Read on to learn more.

DISCLAIMER: several of these plants are toxic when ingested by humans and animals. If you purchase these for your home, be sure to place them in a location out of reach of children and animals. Ask an employee at your local greenhouse for more information or refer to the ASPCA’s website to learn more about plants that are toxic for pets.

What is phytoremediation?

Definition

Phytoremediation, also called ‘bioremediation’, is a plant’s ability to remove pollutants from air, water, and soil. Plants have been a popular choice for centuries in purifying the air and cleaning up human messes in both bodies of water and soil. They are used to clean up toxic spills, chemicals, petroleum derivatives, and heavy metals, to name a few. But how does it work?

Phytoremediation processes

Plants typically use phytoremediation to cleanse their environments using multiple processes, some of which include:

• Phytostabilisation: plants pull up contaminants and chemicals from the soil into their roots, leaves, and stems
• Phytoextraction: plants that are capable of accumulating large amounts of toxins from the soil or air collect toxins in their leaves and stems, then destroy the intoxicated portions
• Phytodegradation: toxins found in the soil are reduced or absorbed by the plant’s root zones when the plant attracts certain bacteria that will degrade those substances
• Phytovolatilization: plants and other organisms convert toxic airborne gases into less toxic forms¹

Source ²

When plants are used indoors to fight against indoor air pollutants, they typically employ one of the two main types of phytoremediation.

Passive systems

This is the simplest and most popular form of using air-purifying plants to combat indoor air pollution. It involves placing potted plants in an indoor space and letting them perform their job naturally. In a passive system, plants remove indoor air pollutants like particulate matter (PM) and volatile organic compounds (VOCs) using deposition and absorption mechanisms².

A 2012 study found that the presence of six indoor plants in schools reduced PM10 concentrations by 30%. The indoor plants also reduced VOC concentrations from 933 to 249 μg/m3.³

This method of phytoremediation is the most practical method for homes and small offices. All it takes is choosing the most effective plants as you will find detailed below in this article.

Active systems

In addition to deposition and absorption mechanisms, active systems also use filtration to remove indoor air pollutants. This is when polluted air is forced through a plant’s substrate. Although a bit less popular because they require more design work, active systems are two to four times more effective than passive systems. They are heavily dependent upon a plant’s root structure, meaning that plants used for active systems must be chosen carefully in order to produce the best results¹.

Active phytoremediation system designs vary substantially depending upon many different factors including size, alignment of plants, soil medium, water and air supply, and more. Active systems must be fairly regulated, never becoming too moist or too dry. An example of an active phytoremediation system may be a vertical green wall that uses specific plants, a water source, and increased airflow. Although effective, these systems are not typically practical in a home. Larger spaces like some offices or warehouses may benefit greatly from an active system to produce substantial air filtration⁴.

The best houseplants for air purification

As mentioned above, certain indoor plants have more powerful air purifying properties than others. It is crucial to choose the right air-purifying plants when aiming to combat indoor air pollution especially as a new houseplant owner. Indoor plants all have different needs regarding care, especially regarding sunlight and watering needs. Read the list below to find the most efficient plants for reducing indoor pollutant concentrations.

Some indoor plants are non-toxic and safe if accidentally ingested. Others, if you choose to install them in your home, should be placed out of reach of pets and children to avoid accidental consumption.

Safe, non-toxic houseplants

• Areca palm or the ‘Kentia’ or ‘Thatch’ palm
• A resilient, elegant plant that produces small flowers and is perfectly adapted to flat living and indirect sunlight
• Make excellent living room, kitchen, and bedroom plants
• Eliminates: carbon monoxide, formaldehyde, trichloroethylene, benzene, and xylene
• Bamboo palm
• Ideal for lower-light living conditions (bamboo palms still thrive even in indirect sunlight), sometimes offshooting small, orange flowers
• Beautiful, green, arching palm leaves on a bamboo palm make it the ideal for both homes (living rooms and bedrooms, for example) and offices
• Eliminates: chemical pollution like formaldehyde, xylene, benzene, and carbon monoxide
• Spider plants
• Incredibly resilient (growing in both bright and indirect sunlight, moist and dry conditions)
• Possible to remove the tiny ‘spiderettes’ from a spider plant to grow your spider plant family: they are perfect as bedroom plants!
• Eliminates: carbon monoxide, xylene, and other air pollutants found in solvents, grout, and adhesives (great for the kitchen!)

Houseplants that are toxic to animals

The following indoor plants are toxic to cats and dogs. Remember: cats are climbers! Ensure that these plants are inaccessible to cats, but keep out of reach for all pets. They may cause vomiting, salivating, and/or dilated pupils if ingested. Most of these plants are resilient and easy to grow, requiring minimal care and thriving in both bright and indirect sunlight.

• Dracaenas
• Known for being one of the most effective plants for fighting against indoor pollutants
• Available in all shapes and sizes and are very resilient
• Dracaenas are ideal for a new houseplant grower learning about plant care: dracaenas thrive even in indirect sunlight
• Eliminates: formaldehyde, trichloroethylene, toluene, benzene, xylene
• Pothos or ‘Devil’s Ivy’
• Adaptable to most light and watering conditions with its large, waxy, green leaves
• Grows up to 8 feet (2.4 metres) long!
• Eliminates: formaldehyde, carbon monoxide, benzene, xylene, and toluene
• Rubber plants
• Recommended by NASA for its effective air filtering qualities
• An extremely low-maintenance, easy-to-grow plant requiring minimal care
• Forms interesting shapes with its green leaves, making them excellent living room, kitchen, and bedroom plants
• Fun fact: rubber makers have historically used rubber plants’ latex sap in the rubber-making process!
• Eliminates: trichloroethylene, formaldehyde, and carbon monoxide; raise oxygen levels

Houseplants that are toxic to humans and animals

The following indoor plants should not be left accessible for anyone who may accidentally ingest it including cats, dogs, and other pets; children; and even farm animals. Most of these plants are resilient, growing in both bright and indirect sunlight.

• English ivy
• An easy-growing, climbing plant with small leaves that adapts to most interior conditions (both bright and indirect sunlight) and requires minimal care
• Eliminates: formaldehyde, trichloroethylene, carbon monoxide, benzene, and airborne faecal particles and mould spores, making it the ultimate houseplant for the bathroom
• Aloe vera
• Bold-textured plants that are accustomed to dry environments, thus requiring minimal watering
• Never leave an aloe vera plant with soil that is too moist; it is recommended to avoid placing it in humid places like the bathroom
• Keep in mind that if you want your aloe vera plants to thrive, they do need full sunlight
• Added bonus: use aloe vera leaves to heal minor burns!
• Eliminates: excess carbon dioxide; raises oxygen levels
• Peace lily plants
• An adaptive plant that grows well in bright and darker conditions (but be careful not to leave a peace lily in conditions that are too dark or its flowers may not bloom) and easy to grow, requiring minimal care
• Peace lily plants may even help dry upper airways – they increase a room’s humidity by 5%!
• Eliminates: ammonia, formaldehyde, trichloroethylene, xylene, and benzene; raise oxygen levels^5,6

Plants remain limited in their purification capacities

A 2019 study found that you would need around 93 houseplants per square foot (10 to 10,000 plants per square metre of a building’s floor space, according to the study) for them to be effective enough to reduce pollutants down to safe levels⁷.

A 2022 study went further and determined the clean air delivery rates (CADR) of certain plants in order to compare them to a standard air purifier:

Source ²

The above plants were determined to have CADRs of between 0.002 to 0.084 m3/h². Compared to standard air purifiers, plants simply cannot compete. The CADRs of Eoleaf devices, for example, are as follows:

• AEROPRO 40: 420 m3/hr
• AEROPRO 100: 570 m3/hr
• AEROPRO 150: 670 m3/hr
• Pure CAR: 45 m3/hr

The best of both worlds

Given the above information, the best way to benefit from indoor plants and the purest air available is to use both in your indoor spaces! Houseplants do help us to fight indoor air pollution, and furthermore, they bring joy and a natural aesthetic to our interior spaces.

Air purifiers are highly recommended for those trying to combat indoor air pollutants. Remember: our interior spaces are 2 to 5 times more polluted than our outdoor spaces. According to the World Health Organisation (WHO), household air pollution is one of the most critical public health issues of our time. Indoor air pollution was responsible for 3.2 million deaths in 2020 alone, 237,000 of which were children under 5 years old. The adverse health effects caused by indoor and outdoor air pollution claim the lives of 6.7 million people annually⁸.

Eoleaf’s air purifiers use an 8-step purification technology used in purifying all three types of air pollution (biological, chemical, and fine particle). Our HEPA H13-certified filters guarantee removal of 99.9% of airborne particles down to a size of 0.01 microns. Our devices remove:

• Germs (bacteria and viruses including COVID-19)
• Allergens (pet hair and dander from cats and dogs, dust and dust mites, pollen, and mould and its spores)
• Fine particle pollution (including PM10, PM2.5, and PM0.1)
• Chemical pollution like VOCs including formaldehyde, a known carcinogen
• Unpleasant odours thanks to our activated carbon filter

In addition to investing and installing an air purifier in your indoor spaces, it is also recommended to improve ventilation and to keep a clean home. Refer to our article on tips to ventilate your space more effectively. Hoover rugs and carpets, mop wooden floors and tile, keep humidity low in bathrooms and laundry rooms, and dust regularly to keep pollutants from accumulating. Also keep humidity levels low and try to avoid using harsh VOC-emitting chemicals in your home like synthetic cleaners and air fresheners.

Our air pollution specialists are available any time to help you choose the right device for you and protect your health. Contact us with any and all questions. Additionally, feel free to refer to our Buying Guide that provides an in-depth look on all of the factors to consider before purchasing an air purifier.

Resources

¹ Pandey, V. C., & Bajpai, O. (2019). Phytoremediation. Phytomanagement of Polluted Sites, 1–49. doi:10.1016/b978-0-12-813912-7.00001-6

² Budaniya, M., & Rai, A. C. (2022). Effectiveness of plants for passive removal of particulate matter is low in the indoor environment. Building and Environment, 222, 109384. doi:10.1016/j.buildenv.2022.109384

³ Pegas PN, Alves CA, Nunes T, Bate-Epey EF, Evtyugina M, Pio CA. Could houseplants improve indoor air quality in schools? J Toxicol Environ Health A. 2012;75(22-23):1371-80. doi: 10.1080/15287394.2012.721169. PMID: 23095155.

⁴ Pettit, T., Irga, P. J., & Torpy, F. R. (2018). Towards practical indoor air phytoremediation: A Review. Chemosphere, 208, 960–974. doi:10.1016/j.chemosphere.2018.06.048

⁵ Prattey, S., & Joyner, L. (2023, March 24). 26 best air purifying plants for the home. Country Living. https://www.countryliving.com/uk/wellbeing/a668/houseplants-to-purify-house-air/

⁶ Riley, E., & Wilson, D. R. (2018, September 18). The Best Air-Purifying Plants for Your Home. Healthline. https://www.healthline.com/health/air-purifying-plants?c=15147792784

⁷ Cummings, B. E., & Waring, M. S. (2019). Potted plants do not improve indoor air quality: A review and analysis of reported VOC removal efficiencies. Journal of Exposure Science & Environmental Epidemiology, 30(2), 253–261. doi:10.1038/s41370-019-0175-9

⁸ World Health Organization. (2022, November 28). Household air pollution. World Health Organization. https://www.who.int/news-room/fact-sheets/detail/household-air-pollution-and-health