Air-purifying Plants

NASA-certified air-purifying houseplants

Hopefully, the heading here is already impressing you. And yes, that is THE National Aeronautics and Space Administration NASA. 

In the late 1980s, NASA partnered up with the Associated Landscape Contractors of America to carry out research into the best methods for cleaning the air in space stations. Following their study, they published a list of plants that help to purify and filter the air. This was a pretty comprehensive list of air-cleaning plants and showed which plants could filter which specific chemicals. The toxins that plants can help remove include benzene and formaldehyde. The principal investigator involved in the study also published more information that we are still using today to help inform our choices of plants.

This document identified that when offices become more energy-efficient, it actually led to a rise in health problems of office workers. There were a few reasons behind this, such as the reduced fresh air exchange, synthetic building materials or furniture that off-gas various organic compounds and also people who may carry germs. Together, these contribute to ‘sick building syndrome’. 

While NASA was looking into which plants to choose for their space stations, the benefits of their work have been far-reaching and influential right on this planet. The research helped to highlight how offices and homes can make us sick and shows there is a quick, easy, beautiful and natural way to go some way to prevent or overcome this. 

The chemicals in our air that plants can filter

If you’re not sure exactly what air-purifying means, then this is where it gets a little scientific. The NASA study looked at some specific chemicals to see what effect the plants had on them. 

Some of the below descriptions of the chemicals and what they can cause may seem a bit scary but don’t forget the quantities we experience on a daily basis are probably on a small scale. However, it is also important to remember that over time they can add up and while you may not be exposed to significant amounts, they’re clearly not doing us any good. Anything we can do to reduce the levels of these is going to be a positive contribution towards your health – so the work that our houseplants do in purifying the air is an important one:

• Benzene – a common solvent that can cause skin and eye irritation. It may also be a contributing factor towards long-term conditions such as leukemia, respiratory diseases and liver and kidney damage
• Trichloroethylene – has a number of uses and is often used in dry-cleaning and printing. It is a potential live carcinogen
• Formaldehyde – apparently found in most indoor environments from paper products to household cleaning agents. It is also in cigarette smoke and heating and cooking fuels. It is an irritant and can cause headaches. Research has shown that it may be behind a rare type of throat cancer seen in people who spend years living in mobile homes
• Xylene – often used as a common component of ink, rubber and adhesives but also as a cleaning agent. It can cause nausea, headaches and dizziness and like many of the above, is an irritant
• Toluene – this is a common solvent used in types of paint thinner, disinfectants glue and explosives (although we hope no one has any need to use it for this!). Low levels of the chemical can lead to fatigue or nausea but long-term it can inflict neurological damage
• Ammonia – the most common use of it as a fertiliser as it can improve crop yields. It has a wide range of other uses, such as treating textiles, cleaning or in the food industry for fermentation or antimicrobial purposes. Ammonia is a corrosive and can cause irritation as well

So which houseplants can purify your air?

Some of the best-performing houseplants when it comes to air-purification are:

• English ivy
• Devil’s ivy
• Boston fern
• Aloe vera
• Sansevieria

Most of the air-purifying plants above don’t filter out every single one of the chemicals above, but they all play a part in helping. They can also improve air quality as they increase humidity levels. This in turn increases oxygen levels and reduces airborne dust. Here is our low-down giving you more detail on the best purifiers for filtering out the nasties in your home or workplace. 

English Ivy

The English Ivy scored incredibly highly for NASA’s air-purification standards, ticking the boxes for all but ammonia. Pretty impressive! It is a beautiful and romantic plant, with its signature trailing leaves. It grows fairly quickly and looks great on a shelf or hanging up. 

Care advice: It prefers less light than other plants so will do well in shady spots. Also make sure the soil is dry before watering, which should be around every 1-2 weeks.

Devil’s Ivy

Another air-purifying ivy with similarities but also quite a few differences. The Devil’s Ivy’s leaves are larger, fewer and more heart-shaped. They can have beautiful patterns in greens and yellow, helping to add a bit of colour to your room. It can climb or hang so see what way it goes and either move it based on its development or try to encourage it by carefully selecting the location you display it in.

Care advice: tough as old boots, it is incredibly easy to care for and will grow nearly anywhere! However, keep it out of draughts and away from radiators or direct bright sunlight as this can scorch the pretty leaves. It needs a water around every 1-2 weeks when the soil feels a little dry.

Boston Fern

One of our favourites, the Boston Fern looks stunning growing out at all angles from its grey pot. Up, down, to the sides – the little feathery fronds will go in all directions. We particularly love the woodland or jungle feeling it gives. Another bonus is that it is non-toxic to cats and dogs! One of our favourite plants, but a particular highlight in this round-up of air-purifying plants, we would recommend the Boston Fern for any office or home.

Care advice: while this is the easiest fern to look after, it does need a bit more TLC. It loves high humidity and beware of letting the soil dry out as this can cause the leaves to drop! Given this, give it a water once a week and avoid direct sunlight to keep those fronds lovely and green.

Aloe Vera

The name of this plant must be familiar – even if you didn’t know that the Aloe Vera was clever enough to filter out benzene and formaldehyde, you must have heard of it in skin creams and other cosmetic products. The Aloe Vera has long leaves that grow fairly straight and each one is full of that lovely aloe gel. I’m sure you’re not surprised this makes the list of the best air-purifying plants.

Care advice: it loves the sunshine and should only be watered when it has dried out a bit. A handy tip is to squeeze the leaves – if they’re nice and firm then it is doing well. 

Sansevieria 

We have written about our beloved Sansevieria on many occasions and that it is because it is simply awesome. We have a few different types with our snakey plant, spikey and little punk. It is another of NASA’s high air-purifying achievers, filtering out everything but ammonia and that may be one of the reasons why it is so popular. Others include how stylish it is and also easy to look after! What a clever air-cleaning plant.

Care advice: for a full debrief on the sansevieria we recommend you read our ultimate guide to the plant. Short on time? Well then what you need to know is that it needs just 300ml of water every few weeks, it lights a bright area of full sun but also handles partial light and you can give it a top-up of generic houseplant feed every couple of months.

Our intricate relationship with plants

As the NASA principal investigator pointed out, “man’s existence on Earth depends upon a life support system involving an intricate relationship with plants and their associated microorganisms, it should be obvious that when he attempts to isolate himself in tightly sealed buildings away from this ecological system, problems will arise”. Having plants in a home can clearly be beneficial for reasons other than style and if small steps, such as having a few green house plants, can actually improve the air quality around you, then there should be no hesitation to greenifying the spaces you live or work in.