Ah, South Korea: a major economic powerhouse of Asia, world leader in technology and a .... superstitious country?
Here's a particularly strange urban legend of "Fan death" where an electric fan, if left running overnight in a closed room, can cause death of those inside. The urband legend is so pervasive in South Korea that manufacturers had to equip fans with a timer switch that turns them off after a certain period of time!
Can an electric fan cause harm to its user? The Korean Consumer Protection Board once stated:
"If bodies are exposed to electric fans or air conditioners for too long, it causes bodies to lose water and [causes] hypothermia. If directly in contact with [air current from] a fan, this could lead to death from [the] increase of carbon dioxide saturation concentration 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."