There was a time in Korea, when the dog days of summer rolled around and started hounding everyone here, that you could count on someone bringing up one of the more interesting urban legends associated with Korea during the hot summer months—“fan death.”

Most assuredly there would be a news story or two about how someone had died while sleeping with a fan on in a closed room as well as an essay or two in the Op-Ed section from some foreigner refuting the notion that a person could die from a fan.

These days I don’t hear about it as much as I did when I first came here (maybe more people are using air conditioning or that people just got tired of hearing about it every time summer rolled around). Nonetheless, fan death is an urban legend that originated in South Korea. 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 the room. Interestingly, this belief also extends to air conditioners in cars (maybe that explains why some taxi drivers will have the air conditioner running in a taxi with one or two windows open). Moreover, fans manufactured and sold in Korea come with a timer switch that turns them off after a number of minutes so a person can go sleep—and if you can excuse the pun—rest assured that the fan will shut off.

South Korea, as far as I know, is the only country that believes in this so-called phenomenon of fan death. To be sure, most of the Koreans I have talked to over the years about fan death from students, teachers, and friends have insisted that fan death does occur. Once, when I mentioned to my students that I slept with a fan on, many of them said I was lucky to be alive.

If you ask any Korean about the validity of fan death they will almost certainly (and vehemently) argue that it is indeed true even though they probably couldn’t tell you how and when this phenomenon of fan death first started in Korea.

How does fan death occur? There is any number of theories, which might make any nonbeliever of a fan death a believer (if you really want to buy into these theories). Supposedly an electric fan creates a vortex, which sucks the oxygen out of the room and creates a partial vacuum or uses up all the oxygen in an enclosed room and creates fatal levels of carbon dioxide. Other theories suggest that if a fan is put directly in front of the face of a sleeping person, it will suck the air away, preventing one from breathing. (How many people actually would sleep with their face right up against a fan?)

Then there’s hypothermia, which results when one’s metabolism slows down at night and makes one more sensitive to temperature. Supposedly, if a fan is left on all night in a sealed and enclosed room, the room’s temperature will be lowered. However, the temperature does not really fall inside the room; instead, the fan would make someone cooler by increasing the convection around a person’s body so the heat dissipates more easily as perspiration evaporates from the body.

Often, believers claim that a combination of these factors is responsible for fan death. Although there is no documented medical proof that sleeping in a closed room can actually cause “fan death” (I haven’t found anything online) this urban legend has been perpetuated by Korean media (everyone believes what he or she read in the Korean newspapers, right?) in the past. Someone is found dead in a room with a fan on and the fan is blamed. Maybe we ought to check with the folks at CSI and see what they have to say?