Do indoor plants purify the air?
Indoor plants have become incredibly popular in recent years, but do indoor plants really purify the air? And how effectively so?
Since the COVID-19 pandemic began, there's been an increasing focus on the importance of indoor air quality since so many of us have spent increasing amounts of time inside.
Further to this, the Environmental Protection Agency (EPA) reports that Americans spend up to 90% of their time indoors, where levels of pollutants can be up to five times higher than outside air. And that's just one of the many reasons why it's essential to ensure the air we breathe indoors is as clean as possible. We wrote about this in our article: Indoor Air Pollution: An Invisible But Deadly Threat.
So, do house plants truly purify the air we breathe? Can they substitute the need for an air purifier? Let us take a look into the science behind plants and their effect on air quality.
How do indoor plants purify the air?
According to the EPA, indoor air quality is mainly affected by volatile organic compounds (VOCs), which can exist in some of the products and materials inside our homes, as well as other gases such as carbon dioxide, carbon monoxide, and nitrous oxide.
Through photosynthesis, plants convert the carbon dioxide we breathe-out and also remove gases from the air through a process called absorption.
In the now famous 1989 NASA report, pioneering scientist Bill Wolverton studied how household plants could provide an alternative help to indoor air quality. Mr. Wolverton studied the ability of plants to remove VOCs from the environment and their potential for use in space-related missions.
Scientists studying the effectiveness of indoor plants found houseplants reported in 2017 in the journal Building and Environment that plants alone make "at best, modest contributions to indoor removal effectiveness". The tests found a few houseplants barely affected the environment. To make a meaningful difference to the air quality of your home, you'd need to drastically increase their concentration, which is borderline impossible in most cases.
But while a single plant won't purify the air enough, a green wall covered in plants just might, found scientists in a study published in 2020 in the Journal of Environmental Management. So, in high enough quantities, plants can improve air quality. But what should we buy?
Which pollutants can indoor plants filter from the air?
According to NASA, the most common, harmful pollutants found indoors are trichloroethylene, formaldehyde, benzene, xylene and ammonia. These pollutants can be found in paints and varnishes, fabrics, smoke and cleaning products.
In high concentrations, these five pollutants can cause dizziness, headaches and irritation to nose, mouth and throat as well as liver and kidney damage. The results of NASA’s study showed two plants that work particularly well in reducing the levels of all five of these pollutants from indoors. These are Peace Lilies (Spatiphyllum ‘Mauna Loa’) and Florist’s Chrysanthemums (Chrysanthemum morifolium).
Do indoor plants have other health effects?
During COVID-19 lockdowns, many of us decided to get our hands dirty and get into gardening – but is there any real health benefit to it?
In May 2021, a study published by the journal Environmental Research, found that houseplants were linked to feelings of "being away while at home" providing a staycation for the mind that improves mental health.
Another recent study from Princeton University found that gardening can be beneficial for physical and mental health. While a third study cited in the Journal Physiological Anthropology found that indoor gardening lowers stress responses compared to the demands of completing a computer task.
Are indoor plants safe for pets?
Introducing more plants and greenery to the home can have benefits, but are indoor plants safe for our pets?
Most people know that Lilies are dangerous to cats and tomato plants to dogs, but many other species also threaten the health and wellbeing of our pets. There are too many to list here but there's a full list of poisonous plants available on the ASPCA's website.
If your pet chews on a plant, it is unlikely it will have to serious consequences. In any case, you should keep the situation monitored, take a photo of the plant (just in case) and call the vet in if you pet starts vomiting or behaving strangely.
9 Best indoor plants that clean the air
Spider plants (Chlorophytum comosum)
Also known as air plants, spider plants grow quickly and look great in hanging baskets, especially in your work space. Sometimes they even produce lovely white blossoms.
Spider plants have more than 200 species and many of them can survive a little forgetfulness from us.
Plant care: Water your spider plants two to three times a week.
Non-toxic: This plant is safe for both children and animals.
Filters: formaldehyde, xylene
Dracaenas are a newbie green thumb’s dream. This large group of houseplants comes in all shapes, sizes, and colors. Choose from the tall corn plant, which has interesting markings, or the rainbow plant, which comes in bright purple.
Plant care: Keep the soil damp but not soggy, as too much water is a kiss of death for this plant.
Toxic to animals: Your cat or dog may vomit, salivate more, or have dilated pupils if they eat dracaenas.
Filters: formaldehyde, xylene, toluene, benzene, trichloroethylene
Golden pothos (Epipremnum aureum)
Also known as devil’s ivy, this plant may be as close as plants can get to indestructible. It flourishes in a variety of conditions and can grow up to 8 feet long. It’s also considered one of the most effective indoor air purifiers for removing common toxins.
Plant care: Water when the soil is dry. You can trim the tendrils when the plant gets too big.
Toxic to animals: Keep this plant out of reach for both cats and dogs.
Filters: formaldehyde, xylene, toluene, benzene, carbon monoxide, and more
Areca palms (Chrysalidocarpus lutescens)
This small plant from Madagascar is easier to grow outdoors. But if you have a space with bright filtered light, its gracefully arching leaves will make a pretty addition to the room.
Plant care: This thirsty plant needs plenty of water during growth, but less in the winter.
Non-toxic: These tall plants and their leaves are non-toxic to both cats and dogs.
Filters: benzene, carbon monoxide, formaldehyde, trichloroethylene, xylene, and more
Chrysanthemums (Chrysanthemum morifolium)
Florist’s chrysanthemums or “mums” are ranked the highest for air purification. They’re shown to eliminate common toxins as well as ammonia.
Treat yourself to a fresh pot, as this flower only blooms for about six weeks. Or you can fertilize the pot again in the spring when new growth appears. But without the flowers, it won’t be purifying the air. If you don’t want to wait, you might want to just get a new pot.
Plant care: Check the soil’s moisture every other day, and keep it damp.
Toxic to animals: Even though it has a friendly name, mums are toxic to both cats and dogs.
Filters: formaldehyde, xylene, benzene, ammonia
English ivy (Hedera helix)
This evergreen climbing plant is well adapted to indoor conditions. Different varieties will prefer different light situations, from bright, indirect light to low-light spaces. It’ll look especially picturesque growing from a hanging basket or around your windowsill.
Plant care: Water generously during growth, but don’t overwater during the winter.
Toxic to animals and humans: Although the English ivy thrives almost anywhere, it’s known to cause problems in dogs, farm animals, and humans when eaten. The chemicals in the sap can also cause severe contact dermatitis in humans, especially those with sensitive skin.
Filters: benzene, carbon monoxide, formaldehyde, trichloroethylene, and more
Rubber plants (Ficus elastica)
Rubber plants are evergreen trees from India. Their roots grow upwards and often become entwined around the plant’s trunk, forming interesting shapes. These plants love bright, filtered light and a little attention now and then.
Plant care: Water moderately to keep the soil moist, especially in the winter. Prune the leaves and wipe them down to keep them looking pretty.
Toxic to animals: Rubber plants are mildly toxic to cats and dogs.
Filters: carbon monoxide, formaldehyde, trichloroethylene and more
Chinese evergreen (Aglaonema)
These evergreen perennials are native to tropical forests in Asia. In addition to looking patterned and colorful, these pretty plants can remove many common toxins. But caring for these plants may require extra attention.
Plant care: Water moderately and allow compost to almost dry out before watering. Chinese evergreens like high humidity, a little regular misting, and getting repotted every few years.
Toxic to animals: Chinese evergreen plants are toxic to dogs.
Filters: benzene, carbon monoxide, formaldehyde, trichloroethylene, and more
Peace Lilies (Spathiphyllum)
In the 1980s, NASA and the Associated Landscape Contractors of America discovered that peace lilies were one of the top three plants for removing common household toxins, even ammonia.
Plant care: Keep soil slightly moist. Peace lilies thrive in most lighting conditions, but too little light can prevent flowers from blooming.
Toxic to animals and humans: Despite its calming name, this beautiful plant is toxic to cats, dogs, and children. It’s best to keep this as an ornamental plant as it can cause burning, swelling, and skin irritation in adults.
Filters: formaldehyde, benzene, trichloroethylene, xylene, ammonia, and more
More ways to purify the air in your home
Besides houseplants, there are other ways you can purify the air in your home:
- Keep your floors clean by vacuuming and mopping.
- Avoid synthetic cleaners or air fresheners.
- Reduce humidity in your air.
- Increase ventilation.
Some studies also used air filters in combination with plants. So if you’re new to planting or don’t have enough room, purchasing an air filter is one easy step to cleaner air.
While plants can make your home a more pleasant environment and taking care of them can have mental health benefits, it's unlikely they'll do too much to purify the air — unless you're going to buy hundreds. So if you're concerned about air quality in your home, we advise you to invest in an good air purifier, preferably one fitted with a high-quality, sustainable filter like KORU's.