Why do we think that plants can purify air?
Indoor plants are believed to have air-purifying abilities due to the findings of a 1989 NASA study, which placed plants into chambers that were two feet wide by two feet long, and filled the chamber with various gases. The study found that plants could reduce the amount of Volatile Organic Compounds (a type of air pollution) in the chambers, which then lead to the belief that houseplants can purify air.
Can plants actually purify the air in our homes?
In a recent study published in the Journal of Exposure Science and Environmental Epidemiology, researchers Michael Waring, an environmental engineer and indoor air quality expert at Drexel University, and study co-author Bryan Cummings reviewed 12 previously published studies about air-purifying plants, then completed their own tests comparing the air-purifying abilities of plants to mechanical air purifiers or opening a window.
While those studies suggest plants can, in fact, remove some toxins in the air, they do so at such a low rate that you would need 10 plants per square foot to achieve the same success of a mechanical air-purifier or airing out a room with open windows and doors.
What does this mean?
The NASA study, and the many studies that have come after it, prove that plants have the ability to purify air. Unfortunately, many of these tests were completed in lab-controlled environments – which are in no way similar to the modern residential home or apartment.
What the most recent study by Cummings and Waring proves is that mechanical air-purifiers, increased ventilation and other methods of increasing air flow are more effective methods of purifying the air in your home than indoor plants.
Are indoor plants worth the money?
Yes! In fact, NASA now has plants growing on board the International Space Station for fresh food, and for their ability to improve the mental state of people.