Purifying Properties of Plants?

In recent years, a surge of indoor potted plants has popped up all over the US, a new trendy, fun, and healthy hobby to improve one’s quality of life. Succulents, ferns, cacti and more are used and advertised as a fun way to keep your life clean and cute. Plants are marketed as the miracle of modern life. They’re claimed to have seemingly magical properties like increasing productivity and happiness.  Another quality that life magazines such as Country Living like to market is that they can purify the air, removing harmful toxins.

NASA, in 1989, conducted a study saying that plants could remove up to 87 percent of air toxins in 24 hours. Due to findings that swamp plants in Florida had been taking in and removing Agent Orange, a tactical herbicide used in the Vietnam War, Environmental scientist Bill Wolverton decided to further his investigation to discover the true air-cleaning properties that plants innately have. He used a tightly sealed bio-chamber in which he conducted his studies, and found out that the plants could, indeed, remove the toxins in the air. This study, being 30 years old now, is hardly much to go off of, yet many vendors and magazines will use it to back up their claims. Recently, however, scientists such as Michael Waring at Drexel University underwent a study to go into deeper depths of what is already known on this topic, and to challenge the findings of NASA in the late 80s.

In this new study, they made a revelation. What NASA had studied was definitely true, but that since these tests were done in a lab, they were unable to mimic the climate and air quality of a standard household. These experiments would place the plant in a small chamber and expose it to large amounts of volatile organic compounds (VOC) that it would then be expected to absorb and purify. The troubling thing is that the data in the study is not incorrect, it just shows that plants can purify the air in small, airtight containers – not full-sized houses. Houses have multiple openings, vents, and materials that must be considered. All of these Wolverton did not consider.

Waring, in order to right the studies that NASA began 30 years ago, decided to calculate the “clean air delivery rate,” (CADR) for the plants. This is the amount of clean air pumped into a room, usually by an artificial air purifier. Unfortunately, what Waring found was enough to make a middle-aged mom cry. Although houseplants do, in fact, cut down on VOCs, the rate at which they do so is much too slow to compete with anything that is already happening within the modern home. Ventilation systems and air purifiers, along with the materials used to build your home are a much bigger factor in in-home air quality.

The harmful thing about marketing plants as modern miracles is that the information has now been proven to be inaccurate. When in need of air purification, instead of breaking the bank on a spectacular new succulent or a quality control fern, one must consider the true pros and cons of indoor plants, removing this misconception from their list.

About Mr. Mohn

Biology Teacher

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