Fan death (http://en.wikipedia.org/wiki/Fan_death).
Fan death is a South Korean urban legend (also found in Japan)[1] which states that an electric fan, if left running overnight in a closed room, can cause the death of those inside (by suffocation, poisoning, or hypothermia). 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.[2]
The Korea Consumer Protection Board (KCPB), a South Korean government-funded public agency, issued a consumer safety alert in 2006 warning that "asphyxiation from electric fans and air conditioners" was among South Korea's five most common seasonal summer accidents or injuries, according to data they collected.[12] Also included among the five hazards were air conditioner explosions and sanitation issues, including food poisoning and opportunistic pathogens harbored in air conditioners. The KCPB actually published the following:
If bodies are exposed to electric fans or air conditioners for too long, it causes [the] bodies to lose water and [causes] hypothermia. If directly in contact with [air current from] a fan, this could lead to death from [an] increase of carbon dioxide saturation concentration [sic] and decrease of oxygen concentration. The risks are higher for the elderly and patients with respiratory problems. From 2003 [to] 2005, a total of 20 cases were reported through the CISS involving asphyxiations caused by leaving electric fans and air conditioners on while sleeping. To prevent asphyxiation, timers should be set, wind direction should be rotated and doors should be left open.
The phenomenon 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.
According to The Straight Dope website, when informed that the phenomenon is virtually unheard of outside of their country, "some locals claim Koreans are uniquely vulnerable due to a peculiarity either of their own physiology or of Korean fans."[4]
(http://borgborg.org/sense-darth-vader-demotivational-poster1.jpg)
Much like Koreans.