How Well Do Houseplants Really Clean the Air?

Introduction: How Well Do Houseplants Really Clean the Air?

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Houseplants are a healthy addiction. They're good for the soul. I did a little research which got me to thinking: how well do houseplants really clean & purify the air? Here are my thoughts.

Step 1:

Houseplants are an blissful addiction for me and I want at least 1 or 2 of them in every room. They make my house a home and really put a smile on my face. I never bought any of them with the purpose of detoxification. As I was preparing for this post and video it got me thinking: how well do our houseplants really clean the air?

My conclusion is at the end but 1st I want to share a few thoughts with you. There’s a complex process called photosynthesis where in a nutshell plants absorb carbon dioxide and convert it to oxygen which they then release. Too much carbon dioxide bad, oxygen good. We, and the earth in general, need photosynthesis to occur.

The study that everyone (bloggers, youtubers, news stations, journalists etc) refers to is the NASA study done in the 1980’s. The plants tested in this study are the ones people mention and highly praise as being our homes’ air purifiers. I had never done any research on this subject, so as I looked as the details of this study, it really got me questioning and wondering.

NASA is the federal agency responsible for our space program. This study was done in conjunction with the Association of Landscape Contractors of America from what I understand was a 2 year period. To me, the results just aren’t conclusive enough – here’s why.

The most important thing I took into consideration is that this study was done in controlled, sealed chambers. They were researching how to keep the air quality good in spaceships, not our homes. Our homes, offices, lobbies, etc are much more complicated environments than a sealed, controlled chamber. No studies have been done on how much houseplants clean the air in typical home environments.

Step 2:

Dracaena marginata or Red Edged Dracaena

1 of the things tested for was formaldehyde, which is found in fabrics, building materials, glues, etc. What they did in the study was inject it into the chamber and then measured the decay with and without plants present. Formaldehyde is constantly being emitted, not just a one time shot. The conclusion as per the US EPA: plants do remove VOC’s , just not significant amounts.

The Association of Landscape Contractors of America did another study in the 1990′s where they conducted controlled experiments with plants on 2 office floors over a 9 month period. Basically, the presence of plants didn’t make a lot of difference in the air quality but the numbers and types of plants weren’t listed. The limited numbers of studies done, including NASA, use the words “may” and “suggest” with no definitive numbers and hard facts to back any of this up.

The amount of houseplants we’d need:

All houseplants clean the air around them. The amount of plants we’d need in a typical room (the estimate of 1 plant per 100 square feet really hasn’t been proven) to make a difference sounds like it would be over 100. There have been no definite numbers as to how many are really needed to be effective. It’s been suggested that a lot of good stuff happens through the microbes in the soil. And of course, the more actively a plant is growing, the more it’ll clean the air.

Step 3:

Sansevierias or Snake Plants

The plants which clean the best, according to the study:

In the NASA study, different plants were shown to remove different pollutants. It makes sense to know which are in your home so you can choose plants which are best at removing those toxins. The number one champion at removing all pollutants is the Spathiphyllum or Peace Lily. Mums, Snake Plants , English Ivy and Dracaenas were right up there too.

Step 4:

Spathiphyllum or Peace Lily

What you can do to help keep pollutant levels down:

An 8″ houseplant releases far, far less oxygen per hour than we humans need. A good way to keep the air healthy in our homes and let as many VOCs out is to open the windows and doors and let as much fresh air in and have it circulate around. Paints are a big culprit so use ones with low or no VOCs. There’s a wide variety of eco-friendly building materials on the market now so that’s another way to keep pollutants out.

This post turned out way different than I originally thought. I’d like to think that my houseplants keep my entire home nice and clean but just having them around is enough for me. Houseplants make my space a much happier place, regardless. Just the presence of plants is grounding and therapeutic.

Bottom line:

No matter how much they do or don’t clean the air, houseplants are so healthy to have in our homes.

What are your thoughts on this? Inquiring horticultural minds want to know!

Happy indoor gardening,


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    2 years ago

    I suspected that the "houseplants are miraculous air cleaners" line sounded a little too good to be true. Nevertheless, I'll keep my little succulent garden, and stop pretending it's magic. Thanks for your very informative instructable, I really appreciate it.