[Fact check] Air purifying plants, how effective are they?

[Fact Check]

■ Broadcast: YTN Radio FM 94.5 (20:20-21:00)
■ Air date: January 18, 2025 (Saturday)
■ Host: announcer Choi Hwi
■ Bold: Selected number fact checker

* The text below may differ from the actual broadcast content, so please check the broadcast for more accurate information.

◇ Announcer Choi Hwi (hereinafter referred to as Choi Hwi): It's a fact check time to point out false suspicious information that needs to be checked. Let's meet Cho Sun-soo's fact checker on the phone. Hello?

◆ Fact checker of Sun Jung-soo (hereinafter, Sun Jung-soo): Yes, hello.

◇ Choi Hwi: Today's fact-checked theme plant. There must be a lot of misinformation about plants.

◆ Selection number: Yes. If anything is intervened, this false information that tries to attract consumers with content that is different from the truth will be judged. The same goes for plants. I'm sure you've heard a lot about "electromagnetic wave blocking plants" and "air purification plants." Today, we're going to check these things.

◇ Choi Hwi: As you said, some people put cactuses in their houses because they said they would block this electromagnetic wave. There are a lot of people who give and receive gifts. Plants block electromagnetic waves. Is it different from the truth?

◆ Selection number: Yes. It's not true. According to the National Radio Research Institute's experimental results, charcoal or cactuses have no effect on reducing or blocking electromagnetic waves. In the case of cacti, it is said that it does not have the effect of blocking electromagnetic waves such as 60Hz. Electromagnetic waves emitted from electronic products such as TVs, computers, hair dryers, and refrigerators are electromagnetic waves in the 60Hz band. Since plants are mostly composed of moisture, the 2.54 GHz electromagnetic waves emitted from microwaves can be partially absorbed. The microwave generates a frequency in the 2.54 GHz band using an equipment called a magnetron inside the cooking room, vibrating water molecules in food and generating heat. However, because the frequency in this band is reflected by the metal, it cannot get out of the microwave. It does not happen for the cactus to absorb electromagnetic waves from indoor electronics unless it is put in a microwave and turned around.

◇ [Choi Hwi] I see. I feel betrayed, too. It's hard to see these days, but electromagnetic wave blocking stickers made of thin metal were once popular. How about this? Is there an electromagnetic wave blocking effect?

◆ Selection number: Electromagnetic wave blocking filters sold on the market have also been found to be ineffective. The National Radio Research Institute announced that there was no blocking effect at all after collecting and testing an electromagnetic wave blocking filter that was attached to a power outlet. When electricity is used, electromagnetic waves are generated not only from power outlets but also from wires or products themselves, so if electricity is used, the generation of electromagnetic waves is inevitable. However, since the intensity of electromagnetic waves generated through wires is very weak, the radio researcher's position is that there is no need to worry about electromagnetic waves if you are a little away. And it has already been concluded that sticker-shaped electromagnetic wave blocking devices are not effective at all.

◇ Choi HW: This round electromagnetic wave blocking sticker. There are a lot of people who put it on the back of their cell phones, and I also put it on. This doesn't work very well either.

◆ [Cho Jong-soo] That's right.

◇ Choi Hwi: Let's go back to talking about plants. It's an air purification plant. This is also selling a lot. It's being introduced through all kinds of media, but I think they prepared it as a theme because they can't clean the air. Does this not work either?

◆ Cho Sun-soo: Yes, it doesn't work. There are also many distribution channels that sell plants that purify indoor air. There are a lot of media reports. Most people use the expression 'air purification plants recognized by NASA of the U.S. space agency'. This screw is not an institution that recognizes air purification plants. Nevertheless, the reason why so many people say 'air purification plants recognized by screws' is that the plants mentioned are mainly leafy tubular plants. You can often find it in shopping malls and media articles that sell these plants. I looked for an article posted on the Korean policy briefing site operated by the Ministry of Culture, Sports and Tourism in November last year. The title is 'Petter Plant 5 Good to Put in the Office'. I'm introducing a plant called Stucky, and the content is like this. It is a plant that has the ability to purify pollutants in the air and has the effect of blocking electromagnetic waves. ’ Let me introduce you like this. And in April 2019, the Hankook Ilbo said, 'See you at Shinsegae Department Store, the air purification plant selected by NASA. I reported an article about it. It was an article in this industry that the department store industry will hold an event to sell air purification plants for the first time.

◇ Choi Hwi: Recently, there have been many articles about the effect of removing fine dust from the tiger thorn tree on the fruit medium of love. Then, are the plants such as Stucky and tiger thorns that you mentioned not effective in purifying indoor air?

◆ Selection number: The National Institute of Biological Resources of the Ministry of Environment distributed a press release last month. When I experimented with native plants in Korea, I found that in some species, compared to a plant called Skynapsus, which NASA recognized as an air purification plant, the air purification ability was better. ’ This was included in the press release. To introduce it in more detail, it was confirmed that the eight types were effective in removing fine dust: △ tiger thorn, △ horn stone, △ tail of the big peak, △ tail of the big peak, △ tail of the big peak, △ sunflower, △ pepper, and △ mountain hydrangea, and △ island long flower, △ rose, △ rose, △ rose, △ rose, △ rose, △ rose, △ rose, △ rose, △ rose, and 하늘 rose, were effective in removing total volatile organic compounds. ’ This is what this press release contains. In particular, the Korea Institute of Biological Resources said, "The tiger thorn tree, known as the Christmas tree decoration and the fruit of love, had 1.4 times higher per hour than the skindapsus and about twice as much fine dust removal. ’ I emphasized it like this.

◇ Choi Hwi: It says that Korean native plants have a better air purification effect than the types recognized by NASA. Then, has NASA done any research on air purification of plants?

◆ Selection number: I looked for a paper published by NASA in 1989. It's been a long time. The title is like this. It's about landscaping plants to reduce indoor air pollution. In the study, NASA used 12 plants to test whether they could reduce the contamination of benzene, trichloroethylene, and formaldehyde. I did it with plants such as bamboo palm, Chinese evergreen, and English ivy. The researchers said, 'Indoor plants and activated carbon filters that require less light have shown the potential to improve indoor air quality by removing trace amounts of organic pollutants from the air in energy-efficient buildings. ’ That's how I evaluated it.

◇ Choi Hui: Air purification plants recognized by NASA, I thought these were some advertisements that were not true, but it's true that NASA chose air purification plants.

◆ Selection Water: The results of this study do not mean that plants effectively remove pollutants from indoor spaces in houses. First, if you look at the experimental conditions of the paper. The experiment was conducted in a cube-shaped space with one corner of 0.76 meters. It's called the chamber. This plant wasn't just planted in a pot, it was also combined with an activated carbon filter. And the purpose of this study was to find a way to filter pollutants out of the air so that astronauts can live healthy in enclosed spaces like space stations. It's completely different from the real-life conditions we live in. Michael Waring, a professor of architectural and environmental engineering at Drexel University in the United States, reviewed and reproduced 12 different papers on plant air purification in this confined space. 196 experimental results were calculated and analyzed. In November 2019, I posted this result in a journal called the Journal of Exposure Science and Environmental Dynamics. The title is like this. 'Fossils do not improve indoor air quality: a review and analysis of volatile organic compound removal efficiency'

◇ Choi Hwi: You mentioned a paper entitled Potting does not improve indoor air quality. For some reason, plants seem to improve indoor air quality, but that's not the case.

◆ [Cho Jong-soo] Yes, that's right.

◇ Choi Hwi: Can you tell me more about it?

◆ Selection water: The researchers expressed the results of several experiments in units of clean air transmission rate, CADR. This is the volume of clean air supplied in 1 hour, in cubic meters per hour. The higher this number, the more air it purifies per unit time. According to the study, the air purification rate of air purification plants averaged 0.023 cubic meters per hour, showing very low efficiency. If general air purifiers are expressed as CADR indicators, they are formed between 10 and 100. But if you look at this air purification plant, it's 0.023, so it's very inefficient. This means that you need to have 10 to 1,000 pots per square meter to remove pollutants as much as they are removed through ventilation in general buildings. As you know, 1 square meter is an area of 1 meter each by 1 meter, and you have to put 10 to 1,000 pots here. This is a story that is not possible in real life.

◇ Choi Hwi: I think there's virtually no air purification rate. Why is the term NASA-recommended air purification plant so widespread?

◆ Cho Sun-soo: As I said earlier, can NASA filter out cancer-causing chemicals from the space station? I did a study to find out about this. Because when you go into space, you have to live in an enclosed space, and carcinogens can harm the health of astronauts. This study has been conducted and it has been shown to have a distinct effect. In small, enclosed spaces, up to 70% of toxic pollutants in the air were removed in a single day. But as I said, the experiment site was a very narrow closed space. We put one pot in this space, we injected one type of volatile organic compound, and we looked at how much it decreased over time. However, in real life, this method cannot be applied. Over time, these experimental conditions were buried and only the experimental results were highlighted, resulting in inflated air purification effects of plants. Since then, subsequent studies have also been carried out ignoring the environmental engineering aspect, and have deviated from their original context, the aforementioned researchers Michael Waring pointed out. The indoor space we live in is not sealed unless it's a really special place, a sterile room or something. The air naturally comes in and out. And it's not as narrow as this lab space. In order to control the experimental results in real-life spaces, it is not enough to place potted plants without any time to step. It's almost fraudulent to say that placing a couple of plant pots in your home that are good for air purification can improve indoor air quality.

◇ Choi Hwi: So it worked in a special environment called outer space. However, should we organize that there is no air purification effect in our daily living indoor space?

◆ Selection number: Yes, exactly.

◇ Choi Hwi: But why did Korean government research institutes release this press release?

◆ Sun Ji-soo: I asked this National Institute of Biological Resources, which I personally issued a press release. If any citizens who have encountered the press release have attempted to clean indoor air quality by relying solely on plants without ventilation, do you think this is a recommended method to maintain proper indoor air quality? ’ I asked like this. Here's the response from the resource officer to this. "According to the results of the study, plants can play an auxiliary role in improving indoor air quality, and through a press release, we wanted to introduce and inform native plants that have better air quality improvement effects. ’ That's what I said. I also added this story. This study was conducted to promote a wider variety of native plants growing in Korea, not plants imported from foreign countries, and to help these native plants help people's living health. As interest and demand for companion plants are on the rise, we hope that the results of this study will contribute to the public's interest and choice of native plants and contribute to the increase in native plant production in related business fields. ’ Like this.

◇ Choi Hwi: Of course, it's a good thing if Korea's native plants become industrialized and sell a lot. If you believe in press releases from these research institutes and rely only on plants without ventilation, you can't maintain good indoor air quality.

◆ [Cho Jong-soo] That's right. In this way, research closely related to people's lives should be conducted by creating experimental conditions similar to real life conditions. Inevitably, if experiments were conducted under conditions different from those in real life, it is necessary to clarify these limitations of how the research results can be applied in this real life, or how they differ or cannot be applied. No matter how much such research was done to make Korean native plants loved by the people, we should have considered how the people would accept it. How the media reported the results of this study is. "The fruit of love, tiger and thorns, improves indoor air quality in winter." It also has an air purification effect on the fruit tree of love. ’ That's how I'm taking it. The general public said, 'If you put this tree in your house, the indoor air quality will improve. ’ That's what you're going to think. But in fact, we don't talk about how much of this tree should be put in to improve air quality. I don't say that it's a level where you can't really expect an effect. It's good to emphasize the air purification effectiveness of native plants compared to foreign plants, but how much of it is needed to actually purify indoor air, and how efficient it is compared to venting by opening windows. It can be said that it is a study that can be applied to real life only when these things are told. The media also needs to check and ask whether such research can be implemented in real life instead of just copying press releases.

◇ Choi Hwi: Thank you for your words today. Thank you.

◆ Cho Sun-soo: Yes, thank you.

◇ Choi Hwi: This has been fact checker of Cho Sun Soo.