Do houseplants clean the air?

Between increased wildfire smoke throughout 2023 and COVID-19, many people want to know how they can at least make the air in their homes purer. Enter the idea of house plants. 

Easy to place around, inexpensive to purchase and an immediate uplifting addition to any décor style, it’s easy to see why the belief of house plants cleaning your air would be an appealing one. 

Plus, there’s the idea that since they take in carbon and produce oxygen, maybe they’d clean the air in other ways, too. Unfortunately, plants do not clean air, and we’ll explore why. 

Why does everyone believe plants clean the air? 

It’s a common statement that house plants can clean your air. 

The origins of this belief can be traced back to a 1989 NASA study. It looked at using different types of plants to reduce air pollution in combination with a type of carbon filter.  

The study did state: “Low-light-requiring house plants, along with activated carbon plant filters, have demonstrated the potential for improving indoor air quality by removing trace organic pollutants from the air in energy-efficient buildings.” 

Just by reading that statement, you may be able to see how easy it is to assume house plants can be of some benefit. 

The biggest misconceptions of the NASA Clean Air Study

There are a number of problems with taking this study at face value. These include: 

1. The study wasn’t for home use  

The NASA study looked at improving air breathability in large-scale work settings. Simply placing plants in your home and expecting them to clean the air is an apples-to-oranges situation. 

2. It’s an old study

It’s important to reiterate that the NASA experiment was a decades-old study from 1989. A further memo from the U.S. Environmental Protection Agency in 1992 stated that someone would have to put 680 house plants in their home to meet the same results of the NASA study, which happened in a test chamber. 

3. The study used carbon filters 

That’s right, the study used carbon filters in addition to the plants. 

The study went on to state: “Activated carbon filters containing fans have the capacity for rapidly filtering large volumes of polluted air and should be considered an integral part of any plan using house plants for solving indoor air pollution problems.”

In short, even by the measures of this study, placing plants in your home is not the way to magically get perfect, clean air.  

4. At best, results are modest

One study only found that house plants had a 0.9 – 9% to indoor ozone removal effectiveness.   

5. Other studies outright suggest plants cannot remove VOCs

A literature review in Nature from 2020 discussed how someone would need to place 10-1,000 plants per square meter to equate to the same VOC removal that already happens when outdoor-to-indoor exchange happens in modern buildings. 

Another problem with the NASA study is it looked at increasing air quality in old energy-efficient buildings from the 1970s, where air quality was already remarkably poor.  

6. It would take genetically modified plants to clean the air 

A startup called Neoplants wants to grow genetically modified plants specifically with the purpose of being able to clean harmful chemicals from the air. 

6 science-backed benefits of indoor plants (beyond cleaning the air)

None of this means you should throw the fern plant from grandma’s estate out the window.  There are very real emotional, mental and health benefits to house plants.

1. House plants may make you healthier

One study suggested that house plants can even improve diastolic blood pressure.  

2. House plants can help improve your grades

The same review as above also found that house plants may help with academic achievement. Another study found that adding indoor plants to classrooms helped improve self-reported attention and well-being.   

3. The most beautiful house plants create the most well-being 

Research found that the more beautiful the plant was to those surveyed, the higher the participants rated their subjective well-being. Some of the most popular plants were bright, leafy specimens like palms, Ficus plants and Epipremnum.

4. Greenery even helped people feel better during lockdown 

Another study looked at how house plants or green window views helped students at home during Covid-19. Greenery both indoors and outdoors helped support the mental health of the participants.  

5. House plants can improve your mindfulness skills

One study looking at Chinese adults suggested that those who care for indoor house plants reported more mental well-being and had a greater mindfulness trait.  

6. You may feel physically better with house plants

In addition to reporting increased positive emotions and less negative feelings, one study found that house plants helped reduce physical discomfort in participants. 

Final thoughts

It turns out that, no, house plants are not magical little air purifiers straight from nature. This assumption has its origins in a 1989 NASA study that sought to use house plants in conjunction with carbon filters to clean up the air in 1970s energy-efficient work buildings. That doesn’t mean house plants are useless: they may make us healthier, happier, help with grades, reduce discomfort and even make us more mindful. Yet they’re still not air purifiers.  

If you want truly clean indoor air, you’ll still need to use a mechanical air purifier. An air purifier works by forcing dirty air through a series of filters to remove large particles like dust, odors and even bacteria and PM 2.5 particulates. You can see the process here:

As beneficial as your house plant may be, it’s no match for a HEPA filter. You can review some of the best air purifiers in our guide.