Last year when I was in Korea I learned about the phenomenon “Fan Death”, which quite astonished me. How could a simple fan kill a man while he's asleep in a room with windows closed? In other words, why must the window be open when you're running a fan the whole night?
Do you have any idea where the myth of Korean "Fan Death" might have originated from? And why practically all Koreans to this day still believe in it so vehemently?
Dear Donghun and Sandra,
The Korean wishes to start the New Year off with a bang, and what better topic than the fabled Fan Death to do that?
Let’s take first things first. Here is the definition of Fan Death: Koreans believe that during summer, in an enclosed room (i.e. all doors and windows shut), an electric fan running directly on your body could kill you while you sleep. Elderly, children, and people sleeping drunk are at the greatest risk. To prevent this, Koreans either open a window a crack, or use a button on the fan that makes it either oscillate or shut off after a certain amount of time.
How does a fan kill? The most common explanations that Koreans generally offer are two. The most prevalent explanation is that the fan used directly on your body causes suffocation, because the fast-moving air around your face makes inhalation difficult. Alternatively, some Koreans also offer that breathing through skin constitutes a significant proportion of breathing, and the fast-moving air caused by the fan makes the skin-breathing difficult, leading to suffocation.
The other prevalent explanation is hypothermia, i.e. abnormally low body temperature. The idea is simpler – fan lowers body heat through dehydration, ultimately to the extent that it could kill.
If these explanations sound ludicrous, that’s because they are.
The Korean has had a complicated relationship with Fan Death. The Korean definitely believed in Fan Death while living in Korea. There was no reason not to – everybody believed in it, and the media reported a case of fan death around once or twice every summer. (Like this article, for example.)
Then, once emigrated to America, the Korean was astonished to learn that only Koreans subscribe to this idea that fans could kill. Once the Korean thought about the explanations he had heard, it was plain that they made no scientific sense. As the Korean went through his self-hate phase (because to varying degrees, all Korean Americans go through this at some point in their lives,) he thought fan death was a prime example of how Korea remained primitive.
The Korean was not the only one who thought that way. Until the recent Mad Cow protests, Fan Death has been the favorite topic of anyone who wished to ridicule Korea. Belief in Fan Death is supposed to show that Koreans lack “critical thinking”. There is a whole website devoted to it: www.fandeath.net. The Wikipedia page describing Fan Death is, reading between the lines, dripping with contempt. Even a good-natured Korean blog like Stuff Korean Moms Like uses the Fan Death picture to describe the strangeness of Koreans. Similarly, requests at Mythbusters (best show EVER) asking to debunk Fan Death are interspersed with such bile as: “Do you seriously expect anyone to do a TV program to determine whether untold generations of inbreeding on the Korean Peninsula resulted in a bizarrely maladaptive genetic defect that would cause the carrier to die from a slight breeze on their face and this defect finally manifested itself only after the invention of the Electric Fan?”
All of the above is fine and good, except… Fan Death is real.
Here is the science of how a fan could kill. Remember the conditions under which Koreans say Fan Deaths happen – summer (=heat), enclosed room, fan directly on the body. An electric fan cools your body in two ways: by pushing cooler air onto your body, and by allowing your sweat to dry rapidly and take away heat in that process.
But clearly, the fan does not generate the cool air on its own, unlike an air conditioner. And eventually -- especially if you are a passed-out drunk who is already somewhat dehydrated from the alcohol -- your body will run out of water to turn into sweat. So what happens when it is very hot, but the entire room is enclosed such that no cool air comes in from outside, and you have no more sweat to cool your body with?
turbo oven. Turbo oven is a conventional oven that has a fan inside that continues to blow air onto the food. This oven is known to cook at lower temperature than a regular oven, yet cook more quickly. Similarly, in a heated room without an outside source of airflow, very hot air is constantly pushed directly to your body, which is a far more effective way of raising your body temperature rather than “baking” in hot air. If you get enough of this, you would die – of hyperthermia, or abnormally high body temperature.
So Korean people had it right after all – fans can kill. They just tend to give the wrong reason.
Common objection to this explanation is: in such an oppressive heat, the person would have died from hyperthermia anyway, with or without the fan. This objection underestimates the effectiveness of the fan raising the body temperature.
Humans maintain body temperature by developing a thin layer of air around their body that is similar to their body temperature. Because air is a poor conductor of heat, the layer of air around the body adapt very slowly to the temperature of the surrounding air, maintaining steady temperature.
This fact can be proven in several ways. Cold days with strong wind feel much colder than cold days without any wind, because the wind takes away the air layer around the body. Dressing in layers is more effective to keeping warm than dressing in a single thick outerwear. You can do fine wearing only a T-shirt and jeans in 70 degree Fahrenheit air, but you would get really cold wearing T-shirt and jeans in 70 degree Fahrenheit water, because water is a much better conductor of heat. To prevent losing heat, divers wear a wetsuit, which limits the amount of water touching the body, essentially creating the same thermal layer with water.
This method of temperature maintenance works the same way in heat. Although body temperature above 104 degree Fahrenheit (40 degree Celsius) is life-threatening, humans can go on living for hours in temperature much higher than that. How? Humans sweat, and when the sweat drops evaporate, the air around the body cools because of the evaporation. As long as the cool layer of air surrounds the person, the person’s body temperature remains stable.
But if the fan runs directly on the body, that layer of air is taken away, replaced by the same hot air in the room. The room temperature might remain the same, but the body will feel hotter. To compensate, the body would produce more and more sweat, but the sweat would quickly evaporate without offering any protection to the body because the fan is constantly blowing hot air. At some point, the body would run out of water to produce sweat. And starting from this point, the body temperature would rise dramatically.
How dramatic? Turbo ovens can cook the same amount of food at the cooking temperature that is about 50 degree Fahrenheit (30 degree Celsius) lower than a conventional oven. Once the human body loses the ability to regulate heat, it is just like a piece of meat in a turbo oven. In fact, for the purpose of avoiding hyperthermia, human body is worse than a piece of meat -- because it internally generates heat. Keep in mind that Korea’s summertime routinely hits 90 degree Fahrenheit (around 31 degree Celsius). This means that although the room’s air temperature is 90 degree Fahrenheit, with a fan on, your body is cooking at the same rate as being in a room with 140 degree Fahrenheit (61 degree Celsius), plus the rising body heat that is not mitigated by the evaporating sweat. Needless to say, this would kill you – especially so if you do not have a body that controls temperature well, i.e. drunks, children, or elderly.
Don’t believe the Korean? Would you believe the U.S. Environmental Protection Agency? This pamphlet from the EPA, at pages 49 and 51, clearly states the hazard of using portable electric fans during high heat. It specifically says “Portable electric fans can … increase the circulation of hot air, which increases thermal stress and health risks[,]” and “DON’T use a portable electric fan in a closed room without windows or doors open to the outside.”
Or how about a climatology professor who works for the National Weather Service? In an interview with NPR about extreme heat warning system, Dr. Kalkstein specifically mentions the danger of fans in a hot, enclosed room (At 13:45 mark): "One piece of advice we tell them not to do is to sit in front of a fan in a hot apartment because it has a convection effect."
A few points to conclude the post.
1. Why are Koreans so concerned about fan death (aside from the fact that it is real)?
Answer: Why not? We are talking about death here. People around the world engage in all kinds of silliness to cheat death. For example, recently the most emailed New York Times article for a few days in a row was about the dangers of “third-hand smoking”, i.e. the health risk posed by cigarette residue remaining in the smoker’s furniture, clothes, or hair, long after the act of smoking was done.
The Korean does not want to diminish the danger of smoking, or even second-hand smoking. But the Korean’s reaction to this article was: Are these people serious? The article says nothing about whether “third-hand smoking” has a measurable effect on health – it simply says there are unhealthy particles, and people don’t know about them. But bad particles are everywhere, with or without previous smoking! How can the article be convincing without talking about some measure of how much bad particles one could ingest through third-hand smoking? Yet the Korean will guarantee that sooner or later, the term “third-hand smoking” will be used by a concerned legislator as she pushes to make more public places non-smoking.
2. Does getting the cause for Fan Death wrong mean Koreans live without critical thinking?
Answer: Of course not. Fan Death is a miniscule part of Korean people’s lives. All they need to do to prevent it is to open the window or press a button. Simply put, Fan Death is not something Korean people think much about.
For a similar example, to this day, there is no scientific consensus about the health benefits of drinking red wine. In fact, the idea that drinking alcohol helps your health is utterly counterintuitive. Yet when Americans say red wine is good for your health, other Americans simply nod in agreement and move on. It is not a point worth debating. Drinking red wine over, say, beer, does not take much effort. And if there is health benefit to it, true or not, it’s simply a bonus.
The same with Fan Death. Unlike the health benefits of red wine, Fan Death is real. And if all it takes to prevent it is as minor as pressing a button, why bother thinking hard about it? Koreans have no urgent reason to debate what the precise cause of Fan Death is.
3. The Korean would place the blame on the misunderstanding about the cause of Fan Death to the Korean media. Korean media has been careless reporting cases of Fan Death. Recently, Korean media itself is realizing this point. According to a Dong-A Ilbo article, there simply has been no scientific effort to prove Fan Death, even in cases where the fan was supposed to be responsible. There have been no papers on this topic, and no autopsy performed on the person who supposedly died from Fan Death.
The Korean will reiterate: Fan Death is real. The causal mechanism is causing death is very clear; Koreans who warn of Fan Death warn of the exact conditions under which such causation would occur; and it is very plausible that such causation will in fact occur in Korea. However, the Korean will say this: Most likely, not all cases of Fan Death reported in Korean media are truly Fan Death.
-EDIT 12/7/09- If you are an expat in Korea and are about to comment on how Fan Death is still impossible, please read this post from Ask the Expat regarding Korea Derangement Syndrome first before commenting.
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