Relationship between Summer Heat Stress (Perceived Temperature) and Daily Excess Mortality in Seoul during 1991~2005

Abstract

This study investigates the relationship between daily mortality and heat stress in Seoul, using perceived temperatures (PT) derived from a heat budget model. During the summer season, observed PT intensity showed the biggest magnitude of summer heat stress from the middle 10 days of July to the first 10 days of August. The elderly (65 and above) were found to be the most vulnerable to heat stress. The threshold PT, with a significant increase in excess mortality, was 38� C. No time lagged effect was observed with summer heat stress, while a high correlation was observed between anomalies in PT and relative deviation of mortality. A comparison of the heat index and the discomfort index with excess mortality revealed that the discomfort index underestimated excess mortality, whereas the heat index could not appropriately explain the increase in excess mortality correlated with the increase in excess heat. In contrast, PT was found to be the weather element that best represents excess mortality due to heat stress, and is thus expected to serve as a more reliable forecast index of human biometeorology.

Comparison of Temperature Indexes for the Impact Assessment of Heat Stress on Heat-Related Mortality

“…Several previous studies used AT [ 10 , 20 ] and PT [ 13 ] as a high temperature indicator with the assumption that they are better indicators of excess morality because they consider health-related weather variables as well as the temperature. However, our main findings indicate that PT and AT, composite weather indexes, do not always act as the best predictors for an assessment of heat-related mortality.…”

“…And the mean, minimum, and maximum temperature; the mean, minimum, and maximum AT; and the mean, minimum, and maximum PT were compared. We did not include the heat index because previous studies concluded that the heat index was not a good predictor for mortality in Korea [ 13 , 15 ].…”

“…On the other hand, Lee et al [ 13 ] and Byon et al [ 14 ] recommended perceived temperature (PT) as derived from a heat budget model as a predictor for heat-related health impact assessments. They reported that compared to the heat index or the discomfort index, which consider the air temperature and humidity, PT takes into account the distinctive regional characteristics of thermal comfort [ 14 ].…”

“…Moreover, it has been found to be the weather element that best represents excess mortality due to heat stress. For this reason, it predicted to serve as a more reliable forecast index of human biometeorology [ 13 ]. However, PT, AT and temperature have not been compared in a heat-related mortality study.…”

Diagnosing Physical Mechanisms Leading to Pure Heat Waves Versus Pure Tropical Nights Over the Korean Peninsula

“…In particular, the extreme heat of day and night can cause the heat‐related illnesses in Korea (Choi & Kwon, ; Kim et al, ; Park et al, ). It is known that the perceived temperature, which is associated with heat stress, is highly correlated with mortality (Lee et al, , ). Meanwhile, the damage of the TN also exists.…”