healthy house institute

4 Free HHI Books:

Creating a Healthy Household, The Healthy House Answer Book, Healthy Home Building, The Healthy House 4th Edition
Your email will only be used as described in our Privacy Policy

Follow us on Twitter



Proud Supporter of:




House Plants - Do They Help Indoor Air Quality?

By HHI Staff

Live plants inside your home can provide a sense of unity with nature. Many people also believe that their house plants will clean their home of air pollution. But will they?


article continues below ↓

We do not strictly control Google ad content. If you believe any Google ad is inappropriate, please email us directly here.


Actually, some early studies by the National Aeronautics and Space Administration (NASA) did indicate that some living plants could provide reduced formaldehyde levels. In their initial research, NASA scientists placed plants inside a sealed chamber, injected a certain amount of formaldehyde into the chamber, then measured the concentration of formaldehyde after a certain amount of time had passed. After a while, the formaldehyde had, in fact, disappeared. What appeared to have happened was the plants metabolized the formaldehyde and used it as food. Later, it was determined that it was actually bacteria on the plant’s roots that did the formaldehyde metabolizing, not the plant’s themselves.


NASA’s early findings have since been challenged. More-thorough research at Ball State University, and at other laboratories, has concluded that house plants (or the root bacteria) simply can’t substantially reduce formaldehyde or other contaminant levels found in indoor air. (Note: Plants can reduce carbon dioxide (CO2) levels, but CO2 is not considered an air contaminant.) In these more recent tests, plants were again placed in sealed chambers, but with a continuously outgassing source of formaldehyde, such as particleboard. (Houses often contain particleboard and other continuously outgassing sources of formaldehyde, so these new experiments were designed to mimic a real-world situation.) The results were disappointing. There was only a slight lowering of formaldehyde levels—no really significant reductions. So, in a real-world situation, where there’s a continuously outgassing source of formaldehyde, plants (or their accompanying bacteria) can slowly metabolize some of it, but not as quickly as additional formaldehyde released.


Interestingly, if you have very many plants in your home, this can lead to a higher indoor relative humidity (from the ongoing watering), and formaldehyde outgasses at a faster rate as the air’s moisture content goes up. So, you may actually increase formaldehyde levels inadvertently. In the end, it must be concluded that, while house plants will create a certain amount of oxygen, they simply aren’t effective air filters in this context.


Even though they aren’t going to substantially improve the air in your home, you’ll probably still like to have a few live house plants around. If so, you might consider choosing either cacti or succulents (plants with thick waxy leaves). Cacti and succulents require only occasional watering and misting, and little in the line of routine maintenance. Without the need for a great deal of water, these plants rarely become contaminated with mold or mildew—a real plus for mold-allergic people. Having lower water requirements also tends to lessen the chances of insect infestations and plant diseases. Finally, fertilizer applications with cacti and succulents are usually kept to a minimum.


(Note: The views expressed in this article are those of the author, and do not necessarily represent those of The Healthy House Institute, LLC.)



HHI Error Correction Policy

HHI is committed to accuracy of content and correcting information that is incomplete or inaccurate. With our broad scope of coverage of healthful indoor environments, and desire to rapidly publish info to benefit the community, mistakes are inevitable. HHI has established an error correction policy to welcome corrections or enhancements to our information. Please help us improve the quality of our content by contacting with corrections or suggestions for improvement. Each contact will receive a respectful reply.

The Healthy House Institute (HHI), a for-profit educational LLC, provides the information on as a free service to the public. The intent is to disseminate accurate, verified and science-based information on creating healthy home environments.


While an effort is made to ensure the quality of the content and credibility of sources listed on this site, HHI provides no warranty - expressed or implied - and assumes no legal liability for the accuracy, completeness, or usefulness of any information, product or process disclosed on or in conjunction with the site. The views and opinions of the authors or originators expressed herein do not necessarily state or reflect those of HHI: its principals, executives, Board members, advisors or affiliates.

House Plants - Do They Help Indoor Air Quality?:  Created on December 17th, 2007.  Last Modified on February 27th, 2011


We do not strictly control Google ad content. If you believe any Google ad is inappropriate, please email us directly here.



Information provided by The Healthy House Institute is designed to support, not to replace the relationship between patient/physician or other qualified healthcare provider.

Education Partners



Popular Topics: Air Cleaners & Air Purifiers | Allergies & Asthma | Energy Efficiency & Energy Savings | Healthy Homes | Green Building
Green Cleaning | Green Homes | Green Living | Green Remodeling | Indoor Air Quality | Water Filters | Water Quality

© 2006-2018 The Healthy House Institute, LLC.


About The Healthy House Institute | Contact HHI | HHI News & Media | Linking Resources | Advertising Info | Privacy Policy | Legal Disclaimer


HHI Info