Fan death: what interviews and published investigations recorded
Fan death appeared in two different kinds of records: interviews about a South Korean belief and investigations of electric fans during heatwaves. The interviews documented people's explanations and a scientist's account of a misunderstanding. The research sought comparisons that could measure particular outcomes. An NPR report from 2015, a Cochrane review from 2012 and later laboratory experiments addressed different questions. Reading those records together requires attention to what investigators observed, what interviewees recalled and which comparisons researchers actually made.
NPR's 9 August 2015 field reporting, preserved by GBH, documented fan death as a belief expressed in ordinary conversation. At Seoul's Namdaemun market, electronics seller Kim Yong Ho described his concern about his grandchildren sleeping beside a fan. Shopper Ah Yun Choi, aged 25, rejected the fear, while her mother, Kim Jong Suk, aged 53, retained concern about older people. These interviews recorded disagreement within a family and a market encounter. They did not measure the proportion of South Koreans holding either view.
The same reporting obtained a direct clarification from University of Miami climatologist Larry Kalkstein. He said a previous interview in Seoul had associated his name with fan death after a misunderstanding. His acknowledgment that fans could create problems in hot conditions had been taken as agreement with the familiar Korean explanation. In the NPR interview, he rejected claims that fans split oxygen molecules or removed oxygen from a room. His clarification distinguished what he recalled saying from the endorsement subsequently attributed to him.
An earlier research record concerned fans during heatwaves. On 11 July 2012, Saurabh Gupta and colleagues published a Cochrane review whose latest electronic searches had been completed that April. The team searched international databases and consulted researchers and policy specialists. Eligible designs included randomized trials, interrupted time series and controlled before-and-after comparisons. The specified outcomes included deaths, hospital admissions and other healthcare contacts. The eligible comparisons concerned groups exposed to extreme weather and specified health outcomes.
No studies met the review's eligibility requirements. Retrospective observational studies existed, usually comparing people with different health outcomes, but their findings pointed in different directions. Some associated fans with better outcomes and others with worse ones. The reviewers therefore could not settle the effects on major health outcomes during heatwaves. That result concerned a particular research setting and evidence base. It did not establish the oxygen-removal mechanism attached to fan death.
In a Cochrane interview published on 17 July 2019, review author Mike Clarke explained the origins of the 2012 project. It had been organized before the London Olympics, when a heatwave could have coincided with the arrival of large numbers of visitors and athletes. Researchers from Canada, Hong Kong, India and the United Kingdom took part, and the work took about nine months. Queen's University Belfast provided methodological support, and the Cochrane Gynaecological Cancer Group in Bath helped the team complete the review. Clarke's account placed the project within preparations for a large international gathering.
Clarke also distinguished the sensation of cooling from measured effects on illness and survival. He wanted a large comparison with random allocation, with a protocol ready before a naturally occurring heatwave. He identified older people in care homes as one potentially relevant population, with close observation of their health during the comparison. Clarke wanted national or international funding to make such a trial ready before the weather event arrived.
A later investigation by Josh Foster and colleagues was published online on 6 November 2021 in the International Journal of Biometeorology, ahead of its 2022 journal issue. The researchers collected data from 23 participants across 300 one-hour trials. Their work compared physical performance in still air and moving air across different combinations of heat, humidity and clothing. The investigation combined human experiments with a biophysical model of heat transfer. Physical work capacity was assessed relative to a cool reference condition, allowing the researchers to compare the amount of work performed across environments.
The laboratory findings varied with the conditions. In some humid environments, moving air increased the amount of physical work participants completed; in hot, dry environments, it could reduce that performance. The authors also compared several indices used to describe heat stress. The universal thermal climate index reflected the changing effect of air movement more successfully than some alternatives. These were measurements of work and physiological responses in controlled settings. The study did not measure deaths across a whole community or identify the cause of an individual death during sleep.
The distinctions between these records are consequential. A market interview established that a particular person expressed a concern. Kalkstein's interview supplied his own account of how his words had been interpreted. The Cochrane review documented which study designs its authors sought and the absence of eligible comparisons in its search. Foster's team recorded outcomes under particular laboratory conditions. Neither a recollection of an interview nor a measured change in work capacity supplied the missing population-level mortality comparison. The historical record contains several forms of evidence with different boundaries.
- NPR field interviews, South Korea’s Quirky Notions About Electric Fans, 9 August 2015, preserved by GBH — www.wgbh.org
- Gupta and colleagues, Electric fans for reducing the health effects of heatwaves, Cochrane, 2012 — www.cochrane.org
- Cochrane, Featured Review: Electric fans during heatwaves, interview with Mike Clarke, 17 July 2019 — www.cochrane.org
- Foster and colleagues, Quantifying the impact of heat on human physical work capacity, part II, published online 6 November 2021; journal issue March 2022 — link.springer.com