In 1989, NASA conducted its famous Clean Air Study to see whether common houseplants might purify indoor air by removing toxins1 in addition to absorbing carbon dioxide and releasing oxygen. It worked, and while plants are still capable of absorbing harmful toxins in the air, new research suggests that potted plants’ ability to improve air quality in the home or office is largely overstated and buries a more effective solution to keeping the air clean.
Writing in the Journal of Exposure Science and Environmental Epidemiology, researchers found that natural ventilation of indoor environments dilutes2
concentrations of potentially harmful air pollutants3
much faster than a plant is capable of extracting them.
"The best way to have a healthy home is to try to reduce indoor emissions4
, ventilate well (especially when doing high impact emissions like cooking), and using filtration for certain pollutants (e.g. particulate5
matter),” study author Michael Waring of Drexel University told IFLScience.
Where NASA and similar studies went wrong is that they conducted their experiments in sealed chambers6
in laboratories, which do not accurately7 mimic8
the many factors that influence our indoor environments.
"In a small office, you would have to have somewhere between 100 to 1,000 plants to have the same air cleaning impact of ventilation at 1 air change per hour," said Waring.
That doesn't mean you should chuck out your plants just yet. Waring says that although houseplants do not clean the air under typical settings, houseplants have many benefits, most of which are psychological.