Heat-illness cases occurring at home in South Korea double when daily maximum temperatures exceed 38 °C [2].
This trend highlights a critical shift in public health risks, as extreme heat transforms indoor living spaces into dangerous environments. While outdoor work remains a primary threat, the increasing danger within the home suggests that traditional cooling methods are insufficient during peak heatwaves.
Over the past 15 years, approximately one-third of all heat-illness patients were injured at outdoor work sites, such as agricultural fields [1], [3]. This long-term data indicates that labor-intensive outdoor roles remain a high-risk category for heat exhaustion and heatstroke.
However, as temperatures climb past the 38 °C threshold, the risk profile changes. People tend to avoid outdoor labor during these extremes, which shifts the burden of illness to indoor settings [2]. This is particularly evident in vulnerable housing areas, such as the "tong-bang-chon" cramped housing in Dong-eui-dong, Seoul.
Residents in these areas face severe conditions where air conditioning is often inaccessible. One resident of Dong-eui-dong said that bubbles form in a glass of water due to the temperature, a level of heat that permeates the entire building.
In Cheongju, Chungcheong-buk Province, the impact on outdoor workers is seen in changed labor patterns. A farmer from Bunpyeong-dong said that they do not work during the day because it is too hot.
Despite these behavioral changes, the doubling of home-based cases [2] suggests that the interior of homes, especially those without adequate ventilation or cooling, can become as hazardous as the fields in which farmers work.
“The proportion of home-based heat-illness cases doubles when temperatures exceed 38 °C.”
The data indicates that extreme heatwaves create a 'trap' effect for vulnerable populations. While workers can avoid the sun by moving indoors, the lack of climate control in low-income housing turns homes into heat sinks. This suggests that public health interventions must move beyond outdoor safety warnings to include indoor cooling support for the urban poor.
