Effectiveness of Heatwave Emergency Alert Messages through Analysis of Floating Population

Abstract

Heatwave emergency alert messages (EAM) not only provide objective information on heatwave occurrences but also include behavioral guidelines, such as avoiding outdoor activities or going out to respond to heatwaves and minimize damage. To investigate the EAM's effectiveness, we analyzed the changes in the floating population during 2021 using Seoul dong-unit and hourly location-based mobile big data. We also examined what socioeconomic and physical environmental characteristics could cause differences in the effectiveness, focusing on the fact that EAM may have different effects depending on regional factors. The findings revealed a notable reduction in the overall floating population of Seoul, ranging from 0.1 to 3.4%. When examined by region, an average decrease of 2.4 to 5.6% was observed, indicating the different effects of EAM by region. Further analysis of regional characteristics highlighted that areas with low EAM effectiveness were characterized by a lower ratio of senior residents, higher employment concentration, and higher accessibility to public transportation. Additionally, the number of household members, gender distribution, average age, and presence of green spaces can contribute to the gap in the effectiveness of EAM between regions.