4 Most Effective Air Purifying Indoor House Plants

A quick Pinterest daily scroll will tell you how indoor plants are blooming as Interior décor. All those ferns and fiddle leaf figs didn’t gain popularity for nothing!

Can Indoor plants really purify the air inside?

With the recent lock-down over the world due to the Coronavirus, we spend 90% of our time indoors indulging ourselves in Work from home, Netflix binging, sleeping or trying out the new MasterChef Season 7 recipes. And all that time exposes us to Indoor Air Pollution.

"Indoor Air Pollution"- Is that even a thing? According to the Environmental Protection Agency, it most definitely is.

Indoor pollution can occur due to a number of factors like furniture, paint, carpets, upholstery, cleaning agents, mold, bacteria etc. All these are releasing Volatile Organic Compounds (VOCs) into the air and constantly exposing us to it. Common VOCs that may be present in our daily lives include Benzene, Ethylene Glycol, Formaldehyde, Methylene Chloride, Toluene, Xylene and Tetrachloroethylene. Benzene is emitted by gasoline, paint, rubber, tobacco smoke, detergent, and a variety of synthetic fibers. Trichloroethylene can be found in paint, lacquer, glue, and varnish. In other words, it’s commonly emitted by furniture and upholstery.

Studies have shown that the percentage of VOCs on the inside is 5X the amount found on the outside. These toxic compounds can have an array of heath effects including conjunctival irritation, nose and throat discomfort, headache, allergic skin reaction, dyspnea, nausea etc.

Indoor plants come with a long set of air-improving qualities and health benefits.They act as natural humidifiers and reduce the Carbon Dioxide levels.  Apart from that they have also shown to reduce stress and improve attention span. Even a limited number of foliage plants scattered across your home can significantly improve the interior environment.

So your houseplants not only visibly appease your eyes but also work a little harder to cleanse the air you breathe.

Indoor Plants can be a little intimidating to keep, especially if you do not have a green thumb. However, these plants are extremely easy to maintain and you have to try pretty hard to kill them. Each kind has its own conditions for survival, so read along to see which plant you are ready to bring home.

For those who would like to skip reading, here is a summary table of how much VOCs are removed by each plant. 

Plant Name	Benzene Removed	Formaldehyde Removed	Toluene Removed
Spider Plant	0.6 to 8.5 µg/m3/day	29 to 90% per day	54% in 72 hours
Arrowhead Vine	40 to 60% in 24 hours	29 to 91% in 12 hours	Effective Removal
Snake Plant	0.6 to 8.5 µg/m3/day	0.08µg/m3 in 1 hour to 5 hours	5.0 to 5.8 µg/m3/day
Peace Lily	3.2 to 26.8 µg/m3/day	0.14 to 0.88 µg/m3 in 5 hours	_
Palm Plants	1420µg/hr	876µg/hr	_

 

Top 4 Air-Purifying Plants

• Spider Plant

For an amateur houseplant parent, this plant is an excellent choice. They are the easiest air-purifying plant you can grow if you are the forgetful type. The major pollutants it removes are: Benzene, Toluene, Pentane, Xylene and Formaldehyde, some of which are major contributors in the printing and rubbing industries. Studies have shown that it can remove benzene and toluene from 0.6 to 8.5 µg/m3/day and formaldehyde upto 29 to 90% per day. It also removes Toluene about 54% in a 72 hour time span. It is also one of the few houseplants that are non-toxic to your pets.

 

To understand this article better, it is important to understand how is the concentration of VOCs measured. It is measured in microgram (or µg). [1µg is equivalent to 1000mg. So if we say that a particular area has a concentration of 1000 µg/ m3 of Benzene, then the plant can remove xx µg of Benzene per m3 in the stipulated time span, ranging between 5 hours to 24 hours, from that particular area.]

How to care for Spider Plants?

Being one of the most resilient plants around, it does not require too much attention. 

LIGHT: The plant loves bright or indirect sunlight with a cooler temperature of around 20℃. They benefit from occasional pruning, cutting them back to the base.

WATER: The plant should be watered well but should not be overwatered so as the soil to turn soggy. Soggy soil will eventually lead to root rot. In fact, the plant prefers to be dried out a bit between watering.

SOIL: Provide them with a well draining soil. Since spider plants prefer a semi-potbound environment, repot them only when their large, fleshy roots are highly visible and watering gets difficult.

TIPS: If you begin to notice spider plant leaves browning, there’s no need to worry. Browning of leaf tips is quite normal and is not harmful to the plant. This is often the result of fluoride found in water, which causes salt to build-up in the soil. It usually helps to periodically leach plants by giving them a thorough watering to flush out the excess salts. Be sure to allow the water to drain out and repeat as and when needed. It may also help to use distilled water or even rainwater on plants instead of that from the kitchen tap or outside spigot.

• Arrowhead Vine or Syngonium podophyllum

Syngonium plants are not just decorative but they also clean the air you breathe and act as anti-pollutants. They reduce airborne microbes and also reduces humidity. Researchers from NASA and other major organizations have approved of this plant as an air purifier, and it tops the list. Syngoniums absorb the pollutants into their leaves, and the toxins go to the root zone where they are transformed into nutrients to be utilized by the plant. Houseplants also emit water vapors that help the plant pull polluted air to the roots where the plant converts the toxins to plant food leading to photosynthesis and ultimately, to oxygen production.

The major pollutants it removes are: Benzene, Formaldehyde, Toluene and Xylene.

Studies have shown that the plant has the ability of removing 29 to 91% of these toxic pollutants from the air in a 12 hour approximate time span with the toxin concentration of almost 15000 µg/m3

How to care for Arrowhead plants?

LIGHT: The plant grows best in bright filtered light. It should never be subjected to direct sunlight, since that would scorch the leaves. If you notice more growth on one side then simply turn the pot because that side is likely to be receiving more light (this will even grow out).

WATER: Water the plant in proper intervals, allow the top of the soil to dry completely. The soil should be moist and not soggy. Avoid overwatering as it will cause root rot. Water regularly during summer/spring also gradually reduces during cold winters.

SOIL: During the growing season fertilize the plant once in a month and avoid it during winters. Syngonium plant looks pretty well even without fertilizing as it is not a big feeder. Use a well-drained fertile soil. The soil pH should range between 5.5 - 6.5

TIPS: It has its own setbacks from time to time, but it always rallies. It can appear to be almost dead, but if you get them back on the right track, with regulated lighting and watering, they become beautiful and full again! That’s why they are difficult to kill and good for those who cannot tend to care too much about keeping plants alive.

• Snake Plant or Sansevieria Trifasciata

The plant soared to popularity after NASA published an article on space station air-purifying indoor plants back in 1989. Though NASA published their article stating that the plant reduces two air pollutants : Benzene and Formaldehyde, studies later showed that the plant was capable of reducing four major pollutants making them one of the most effective toxin-fighting plants you can buy. Apart from that, they also act as amazing anti-allergens, purifying the air of airborne microbes and dust. They produce oxygen at night, making them a good candidate for bedside tables.

Major pollutants the plant removes are: Benzene, Toluene, Formaldehyde and Xylene.

According to a study, the plant has the capacity of removing almost 0.6 to 8.5 µg/m3/day with an approximate room concentration of 33,000 µg/m3

How to care for Snake Plants?

LIGHT: Unlike other house plants, snake plants can tolerate a variety of lighting conditions, ranging from low light to full sun. However, indirect sunlight is always favoured. The ideal placement for a snake plant would be a few feet away from a west or an east-facing window so they can absorb the required amount of sunlight per day. If you notice that the light falls directly on your snake plant, you can either move it away from the window or cover the window with a sheer shade or curtain and your plant will be happy.

WATER: Snake Plants do not require a lot of watering, so depending on the temperature and the soil moisture, watering should be done. Ideally, you can water it once every week or 10 days, depending on if the topsoil is dry or not. Avoid overwatering in winters.

SOIL: Fertilize the plant once in spring and summer. You should use any all-purpose liquid houseplant food. It requires well-draining soil.

TIPS: If you notice that the leaves on your snake plant are looking a bit yellow, it’s a sign that the plant is in distress. This could be due to cold temperatures or overwatering. If you notice the yellow leaves, move the pot to a warmer location, and ensure that the soil dries out completely between waterings.

• Peace Lily or Spathiphyllum 

A long-time favorite among house plant enthusiasts, as in a research conducted by NASA found the Peace Lily to be one of the top indoor plants for cleaning air. This tropical plant breaks down and neutralizes toxic gases like benzene, formaldehyde, and carbon monoxide. Apart from that, the plant also reduces Trichloroethylene which can be found in paint, lacquer, glue, and varnish. While we all appreciate cleaner air, it’s the Peace Lily’s occasional white bloom that makes it such a popular house plant, making the house aesthetically soothing and fresh.

Major pollutants the plant removes are: Formaldehyde, Benzene, Carbon Monoxide and Trichloroethylene.

Studies have shown that this plant has the capacity of reducing almost 0.14 to 0.88 µg/m3  in a 5 hour time span (approximately) with the Formaldehyde toxicity of almost 2500 µg/m3

How to care for Peace Lily Plant?

LIGHT: Peace lilies prefer light partial shade, and can tolerate fluorescent lights. Consider placing the plant six to eight feet away from a north- or west-facing window. It prefers a temperature range of 65-85°F and humid climates. It's best to keep them indoors most of the year and displayed away from any heating or cooling home appliances.

WATER: Water at least once a week and keep the soil moist. Throughout the summer growing season, spritz the leaves with soft or distilled water. Water your plant less often in winter. Even if you forgot to water for a while and find your plant completely depleted with fronds flat over the pot edge, water and spritz right away. One of the great advantages in caring for the peace lily is the fact that it sags a bit when it needs water, essentially telling you when it’s thirsty.

SOIL:Fertilize the plant once a month or every 20 days during spring and summer. Use any well-draining soil for Spathiphyllum. You should not fertilize the plant during winters.

TIPS: Yellowing leaves indicate that the light is too strong, and brown leaves or streaks indicate scorching from direct sunlight. Peace lilies are listed by the ASPCA as one of the common houseplants that are poisonous to cats.  Peace lilies can be sensitive to chlorine. If your municipal water system is heavily chlorinated, fill a container with water and then allow it to stand overnight so the chlorine can percolate out before pouring into the peace lily.

• Special Mention - Palm Plants

Palms are perhaps, the most versatile and stylish plants that stand out as statement varieties and also are power packed with air-purifying benefits. These outdoorsy plants have recently found their domain in the interior spaces with their deep set fringy leaves, low maintenance and neglect tolerant capacity and a great decor item for a corner. Completely foliage variteis, palms family is HUGE! From Areca Palm, Ruffled Fan Palm, Table Palm to Lady Palm, Bamboo Palm and so so many others, there is always a Palm for you!

Major pollutants the plant removes are: Formaldehyde, Benzene, Carbon Monoxide and Xylene.

Studies have shown that this plant has the capacity of reducing almost 1420µg/hr of Benzene and reduces the Formaldehyde toxicity of almost 876µg/hr. 

How to care for Palm Plant?

LIGHT: Palms prefer bright filtered light, and cannot tolerate fluorescent lights. Consider placing the plant six to eight feet away from a north- or west-facing window. It prefers a temperature range of 60-83°F and humid climates. It's best to keep them indoors most of the year and displayed away from any heating or cooling home appliances.

WATER: Water deeply once a week and keep the soil moist. Throughout the summer growing season, spritz the leaves with soft or distilled water. Water your plant less often in winter. Even if you forgot to water for a while and find your plant completely depleted with fronds flat over the pot edge, water and spritz right away. The plant is a little finicky with water, but once you get a hang of them, they can be the best plants to keep around.

SOIL:Fertilize the plant once a month or every 20 days during spring and summer. Use any well-draining soil. You should not fertilize the plant during winters.

TIPS: Yellowing leaves indicate that the light is too strong, and brown leaves or streaks indicate scorching from direct sunlight. An added advantage for these are that palms are absolutely SAFE for Pets! Palms can be sensitive to chlorine. If your municipal water system is heavily chlorinated, fill a container with water and then allow it to stand overnight so the chlorine can percolate out before pouring into the plant.

 

Research & Reference Links used in this article: 

1. https://greenplantsforgreenbuildings.org/wp-content/uploads/2014/09/Dela-Cruz-2014-review-on-phytoremediation-with-indoor-plants-2.pdf
2. https://www.researchgate.net/publication/11158517_Detoxification_of_Formaldehyde_by_the_Spider_Plant_Chlorophytum_comosum_L_and_by_Soybean_Glycine_max_L_Cell-Suspension_Cultures 
3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5480428/ 
4. https://www.researchgate.net/publication/234258743_Investigations_on_Chlorophytum_comosum_ability_to_remove_toluene_from_air_in_a_closed_environment
5. https://greenplantsforgreenbuildings.org/wp-content/uploads/2014/09/Formaldehyde-removal-plant-species.pdf

Author: Swastika Sarkar, Botanist at Leafy Island

About the Author: Swastika is a Botanist who has been into the research in the fields of Environmental Sustainability and Bio remediation with the use of Biological Organisms. She has presented various papers in both national and international conferences on the use of micro-organisms as a method of Phycoremediation and reducing pollutants from contaminated mediums in an ecologically and environment friendly manner.