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Many people in South Korea believe that, when operated in closed rooms, electric fans do not bring heat relief but sudden death, suffocating victims by stealing their oxygen.

Fan death is an urban legend that originated in South Korea, but has since spread to other countries in the Far East. The belief is that an electric fan, if left running overnight in a closed room, can result in the death (by suffocation, poisoning, or hypothermia) of those inside. This belief also extends to air conditioners and the fans in cars. When the air conditioner or fan is on in a car, some people are apt to leave their car windows open a crack to avoid "fan death." Fans manufactured and sold in Korea are equipped with a timer switch that turns them off after a set number of minutes, which users are frequently urged to set when going to sleep with a fan on.

The belief in the myth of fan-death often offers several explanations for the precise mechanism by which the fan kills. However, as explained below, these beliefs do not stand up to logical and scientific scrutiny. Examples for possible justifications of belief in fan death are as follows:

• That an electric fan creates a vortex, which sucks the oxygen from the enclosed and sealed room and creates a partial vacuum inside. In reality, the air pressure at any point in the room varies less than it does during a storm.
• That the fan uses up the oxygen in the room and creates fatal levels of carbon dioxide. There is no actual conversion of oxygen to carbon dioxide happening; unlike a candle, the electric motor in a fan does not alter the chemical composition of the air (apart from creating some ozone if the motor uses brushes, and outgassing from the materials).
• That if the fan is put directly in front of the face of the sleeping person, it will suck all the air away, preventing one from breathing. However, as can be easily verified, it is possible to breathe with one's face in front of a running fan.
• That fanblades chop up air particles (i.e. oxygen molecules) so that the air is no longer breathable, thus resulting in suffocation. If this were true, regular fans could be used to create chemical reactions. However, air ionisers do turn a very small amount of oxygen into unstable ozone.^[1]
• That fans cause hypothermia. As the metabolism slows down at night, one becomes more sensitive to temperature, and thus supposedly more prone to hypothermia. If the fan is left on all night in a sealed and enclosed room, believers in fan death suppose that it will lower the temperature of the room to the point that it can cause hypothermia. Empirical measurements will show, however, that the temperature in the room does not fall, at least not due to the fan; if at all, it should rise slightly because of friction and the heat output of the fan motor, but even this is generally not significant. Fans actually make one cooler by increasing the convection around a person's body so that heat flows from them to the air more easily, and by the latent heat of vapourisation as perspiration evaporates from the body. Furthermore, hypothermia occurs only when the body's core temperature drops below normal, and will not generally be caused simply by cooling of the skin or decrease in the body's surface temperature.
• Often, believers claim that a combination of these factors is responsible. For example, it might be claimed that the decrease in oxygen and increase in carbon dioxide, in conjunction with some degree of hypothermia, could prove fatal to a sleeping person.^{[citation needed]}

Electric fans sold in Korea are equipped with a "timer knob" switch, which turns them off after a set number of minutes: apparently a life-saving function, particularly essential for bed-time use.

The explanation of fan death is accepted by many Korean medical professionals. In summer, mainstream Korean news sources regularly report on cases of fan death.

A typical example is this excerpt from the July 28, 1997, edition of the Korea Herald, an English-language newspaper:

The heat wave which has encompassed Korea for about a week, has generated various heat-related accidents and deaths. At least 10 people died from the effects of electric fans which can remove oxygen from the air and lower body temperatures...

On Friday in eastern Seoul, a 16-year-old girl died from suffocation after she fell asleep in her room with an electric fan in motion. The death toll from fan-related incidents reached 10 during the past week. Medical experts say that this type of death occurs when one is exposed to electric fan breezes for long hours in a sealed area. "Excessive exposure to such a condition lowers one's temperature and hampers blood circulation. And it eventually leads to the paralysis of heart and lungs," says a medical expert.

"To prevent such an accident, one should keep the windows open and not expose oneself directly to fan air," he advised.

When informed that the phenomenon is virtually unheard of outside of their country, some Koreans have suggested that their unique physiology renders them susceptible to fan death (despite the fact that Korean Americans born outside Korea who have never heard of this phenomenon sleep with fans on and do not suffer any ill effects).

• Dr. Yeon Dong-su, dean of Kwandong University's medical school in South Korea.

Many people say that these victims die from lack of oxygen, but that is not true. Hypothermia does not only occur in the winter when it is cold. The symptoms can also take place if a person has been drinking and turns on a fan in a closed room. Most people wake up when they feel cold, but if you are drunk you will not wake up, even if your body temperature drops below 35 degrees Celsius, at which point you can die from hypothermia. It doesn't matter so much about the temperature of the room. If it is completely sealed, then in the current of an electric fan, the temperature can drop low enough to cause a person to die of hypothermia.

—Dr. Yeon Dong-su

Note: It is likely that the symptoms discussed by this doctor are actually due to excessive alcohol consumption, which can decrease body temperature. See, for example: ^[2]

• Gord Giesbrecht, a physical education professor at the University of Manitoba in Canada, is a leading expert on hypothermia.

It's hard to imagine death by fan, because to die of hypothermia, one's body temperature would have to get down to 28 [°C], drop by 10 degrees [Celsius] overnight. We've got people lying in snowbanks overnight here in Winnipeg and they survive. Maybe if someone was elderly and they were sitting there for three days in a sealed room with an electric fan turned on. Someone is not going to die from hypothermia because their body temperature drops two or three degrees overnight; it would have to drop eight to 10 degrees." In addition, "the only way to verify whether someone had really died of hypothermia during the night would be to take a core body temperature the following morning. Waiting three days while the body was in the morgue wouldn't work because the corpse's temperature can drop during that time.

—Gord Giesbrecht

^[3]

• Dr. John Linton at Yonsei's Severance Hospital, who attended medical school at Yonsei University, is the only non-Korean licensed to practice medicine in South Korea.^[3]

There are several things that could be causing the fan deaths, things like pulmonary embolisms, cerebrovascular accidents or arrhythmia. There is little scientific evidence to support that a fan alone can kill you if you are using it in a sealed room. Although it is a common belief among Koreans, there are other explainable reasons for why these deaths are happening.

—Dr. John Linton

• Dr. Lee Yoon-song is a professor at Seoul National University's medical school and works with the school's Institute of Scientific Investigation. He has conducted autopsies on some of the people who have been described in Korean media as having succumbed to fan death.

When someone's body temperature drops below 35 degrees, they do start to lose judgment ability. So if someone was hiking and later found dead, that could be part of the reason. But we can't really apply this to fan accidents. I found most of the victims already had some sort of disease like heart problems or serious alcoholism. So hypothermia is not the main reason for death, but it may contribute.

—Dr. Lee Yoon-song

• Dr. Lee Yoon-song blamed the Korean media for the persistence of the urban legend.

Korean reporters are constantly writing inaccurate articles about death by fan, describing these deaths as being caused by the fan. That's why it seems that fan deaths only happen in Korea, when in reality these types of deaths are quite rare. They should have reported the victim's original defects such as heart or lung disease, which are the main cause of death in these cases. If a Western doctor investigated these deaths, he would say what really caused the death, and say that a fan was beside the victim.

—Dr. Lee Yoon-song

• Kyung Hwa Lee theorizes that a fear of fan death is a remnant of earlier days:

In my time in Korea, when coal was the main way of heating in the winter season, many died of carbon monoxide poisoning while sleeping with doors closed. Maybe, such fear has come down to today...

—Kyung Hwa Lee

1. ^ http://www.awma.org/journal/PreviewDisplayAbstract.asp?PaperID=1575
2. ^ http://www.collegedrinkingprevention.gov/OtherAlcoholInformation/factsAboutAlcoholPoisoning.aspx
3. ^ ^{a b} http://joongangdaily.joins.com/200409/22/200409222123324579900091009101.html

• The Straight Dope - "Will sleeping in a closed room with an electric fan cause death?" 12 September 1997

• Contemporary culture of South Korea
• Urban legends

• South Korean blog entry on the phenomenon
• http://www.fandeath.net