Key Laboratory of Environmental Change and Natural Disaster, Ministry of Education, Beijing Normal University, Beijing 100875, China; Academy of Disaster Reduction and Emergency Management, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China; School of Government, Beijing Normal University, Beijing 100875, China.
Chinese Center for Disease Control and Prevention, Beijing 102206, China.
Sci Total Environ. 2020 May 1;715:136883. doi: 10.1016/j.scitotenv.2020.136883. Epub 2020 Jan 23.
In response to more frequent heatwaves, various regional or national heat-health warning systems (HHWSs) have been developed recently as adaptation measures. A wide range of methodologies have been utilized to issue warnings, as there is no universal definition of "heat event" or "heatwave", nor are there quantified thresholds of human-health tolerance to extreme weather. The performance of these warning systems has rarely been evaluated with actual heat-health data, especially the morbidity data, in regions with severe impact. In this study, we assessed the performance of the Shanghai HHWS based on heat-related illness data collected by the Chinese Center for Disease Control and Prevention (China CDC) and then conducted a comparative analysis among the Shanghai HHWS, the China Meteorological Administration HHWS, the Chinese national standard for heatwave indexes, the heat index adopted by the USA's National Weather Service and the definition suggested by the World Meteorological Organization to understand their potential performance for application in Shanghai and to evaluate the temperature thresholds and different meteorological indices employed. The results show that: 1) during the research period, 50% of heat-related illnesses and 58.2% of heat-related deaths in Shanghai occurred on dates that had no heat warnings; 2) for the current threshold (35 °C), the single metric of temperature outperformed the temperature-duration two-parameter method; 3) different from existing studies, while infants and seniors are deemed as vulnerable population groups to heat, young and middle-aged males were found to suffer more heat-related illnesses in hot weather. More detailed analyses reveal that the performance of heat-health warning systems needs to be evaluated and revised periodically, and warning thresholds utilized must be localized to reflect public tolerance to heat and to address the vulnerability of target population groups. Temperature is the dominant threshold in heat-related morbidity and mortality analysis. While a decrease in the temperature threshold would definitely increase the warning frequency and socioeconomic costs, it might also cause warning fatigue. The trade-off between these two aspects is essential for decision-makers and other stakeholders in HHWS design and improvement.
针对日益频繁的热浪，最近开发了各种区域性或国家级的热健康预警系统（HHWS）作为适应措施。已经使用了广泛的方法来发布预警，因为没有“热事件”或“热浪”的通用定义，也没有人类对极端天气的健康耐受的量化阈值。这些预警系统的性能很少用实际的热健康数据（尤其是发病率数据）来评估，特别是在受严重影响的地区。在这项研究中，我们根据中国疾病预防控制中心（中国 CDC）收集的与热相关的疾病数据，评估了上海 HHWS 的性能，然后对上海 HHWS、中国气象局 HHWS、中国国家标准热浪指数、美国国家气象局采用的热指数以及世界气象组织提出的定义进行了比较分析，以了解它们在上海的潜在应用性能，并评估所采用的温度阈值和不同气象指标。结果表明：1）在研究期间，上海 50%的与热相关的疾病和 58.2%的与热相关的死亡发生在没有热预警的日期；2）对于当前的阈值（35°C），单一的温度指标优于温度-持续时间双参数方法；3）与现有研究不同的是，虽然婴儿和老年人被认为是对热敏感的人群，但在炎热天气中，年轻和中年男性发现患有更多与热相关的疾病。更详细的分析表明，热健康预警系统的性能需要定期评估和修订，所使用的预警阈值必须本地化，以反映公众对热的耐受程度，并解决目标人群的脆弱性。温度是与热相关的发病率和死亡率分析中的主导阈值。虽然降低温度阈值肯定会增加预警频率和社会经济成本，但也可能导致预警疲劳。这两个方面之间的权衡对于 HHWS 设计和改进的决策者和其他利益相关者至关重要。
