There are many reasons why you’d want to have house plants in your home or office. One benefit that often pops in people’s minds is that plants can help clean the indoor air. But is this true? An extensive review of decades of research says: No. The review, published this month in the Journal of Exposure Science & Environmental Epidemiology, examined a dozen studies that tested how potted plants might reduce indoor air pollutants over time.

You might be wondering: if it’s wrong, why is the common notion that house plants can purify the air in your home so popular? While the review article’s conclusion is clear — the title literally starts with, “Potted plants do not improve indoor air quality” – the studies it examined don’t have the same clarity. The answer boils down to differences in environment between the experiments and an actual office or home. 

Past experiments involved potted plants being placed in small, sealed chambers. The scientists in these past studies then injected some volatile organic compound (VOC), a common class of indoor air pollutant, into the air and measured how much its concentration decreased over time. The experiments often lasted for hours or even days in order to detect a significant drop in air pollution. This does demonstrate that plants will remove pollutants from the air, but they do so incredibly slowly. That creates a problem when trying to extend these results to a house or an office space, which is what much of popular media has done with these past research findings. In the average American home or workplace, indoor air is actually replaced by air from outside in about an hour. That’s much faster than a plant can remove pollutants from a room.

To see how many plants you’d need to clean the indoor air, the review’s authors took the past observations and extended them to larger rooms and a larger number of plants. They found that even if you had a potted plant for almost every square foot of your home, the natural ventilation of the building would still being doing most of the work at getting rid of VOCs. (VOCs largely come from indoors in the first place, e.g. from cooking or using air fresheners). You’d need close to 10 plants per square foot before potted plants start cleaning the air at almost the same rate it’s removed via exchange with outdoor air!

The authors recommend future research efforts shift to environments that have the basic indoor process of exchanging air with the outside. Until then, if you want to better clear the air in your home, maybe just open a window.

Managing Correspondent: Jordan Wilkerson

Original Scientific Article:

Potted plants do not improve indoor air quality: a review and analysis of reported VOC removal efficienciesJournal of Exposure Science & Environmental Epidemiology

Image Credit: “Plants” by flyover is licensed under CC BY-NC-ND 2.0 

10 thoughts on “House Plants Don’t Really Clean Indoor Air

  1. Perhaps I’ve missed something. Could the author kindly direct me to any actual phytoremediation studies that were undertaken under real life conditions i.e. a home / apartment / office etc that is currently in use? Would be interested to review the results where the existing air pollutants (type and quantity) are first measured prior to and then after introduction of a phytoremediation system for various time points? The results would of course be specific to that particular ‘space’ at a defined time frame but nevertheless could prove insightful and informative.

  2. I am living in the city. I vexed with dryness. The Photosynthesis is very true we know .
    The greenery definitely gives goodness to the health , mentally and physically also .
    How many reacerches are giving statements differently no one can say that plants are not good for homes .
    Maybe Nasa proposed plants are best ,but no plant is bad in the concrete jungles and the Plastic world .
    Definitely plants are good friends 😊 even though they can’t move .
    Plants 🪴 give very good air undoubtedly , they give awareness than before . Definitely plants turn lives into healthier ways . Start growing plants Around the area , how much small place it is 🪴 🪴 plants turn lives into ☺️ definitely healthy lifestyle. It is true.
    No researches are nessassary to say plants are good for human s .

  3. I live in a city and keeping the windows open pretty quickly results in sooty surfaces. How do I determine whether the value of ventilation is countered by the pollutants that come indoors from open windows?

  4. However, plants live in a home so do their magic along with the mechanical devices used. A simple test for me was sneezing. I have always used air cleaners, but sneezed a lot, especially in mornings where I had no portable air cleaners. After putting a few plants into my office, which has no air cleaners, I sneeze much less in the mornings, almost not at all. The tests are for a limited time and not for a home where plants live for years. Cumulative results vary from the test. Try plants to see if they clean smells and irritants in your home. Watering plants also adds natural humidity to dry winter air inside.

    1. Plants helping with allergies has nothing to do with cleaning the air. Plants definitely do not clean allergens like pollen, dust, pet dander, mold spores, etc out of the air in the slightest. Your allergies changing is not a result of “cleaner air”. People outgrow allergies all the time, and allergies change as we age. That’s perfectly normal.

  5. While this study is helpful generally there is some contradicting information available. I think it’s important to remember the types of spaces can vary greatly.
    The Potted-Plant Microcosm Substantially Reduces Indoor Air VOC Pollution: I. Office Field-Study
    September 2006Water Air and Soil Pollution 175(1):163-180
    DOI: 10.1007/s11270-006-9124-z

    1. Agree, all scientific research needs to be cross referenced in detail. However, the article you cite above consists of multiple sponsored research papers from between 20-30 years ago. The science will always move on but in this instance we have proven research that house plants do not have a material effect on the air we breath in a closed environment, from an academic institution.

      1. It really depends on the home. Most older homes like mine built in 1910 have gaps that bring in air (and mice). I do hope to construct a home one day with double walls and is sealed well, so well in fact that it would need a system to bring in and filter air from the outside.

        While house plants might not filter the air as much as we hope, they bring joy, which is probably as important.

  6. Filling your house with potted plants might make you happier and more productive, but it’s not going to make the air you breathe any cleaner. That is, unless you had a ludicrous number of indoor plants: somewhere between 10 and 1,000 for every square metre of your living space.

    Nice article and conclusion. Thank you

  7. It was interesting when you talked about how ventilation would still be doing most of the work even if we had a plant in every square foot of our home. I was thinking about buying some potted plants for my home to see if they might help the allergy-like symptoms my husband and daughter have been having. I’ll have to look into more effective methods like duct cleaning now that you’ve taught me about the importance of the ventilation system!

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