Wegener Centre for Climate and Global Change, University of Graz, Brandhofgasse 5, Graz, 8010, Austria.
Aerosol and Climate Lab, Division of Ergonomics and Aerosol Technology, Department of Design Sciences, Faculty of Engineering (LTH), Lund University, Lund, Sweden.
Int J Biometeorol. 2024 Dec;68(12):2495-2506. doi: 10.1007/s00484-024-02783-6. Epub 2024 Sep 20.
Exposure time to heat is increasing with climate change. Heat exposure thresholds are important to inform heat early warning systems, and legislation and guidance for safety in the workplace. It has already been stated that thresholds can be lower for vulnerable groups, including the elderly, pregnant women, children, and those with pre-existing medical conditions due to their reduced ability to thermoregulate their temperature or apply cooling strategies. However, the Wet Bulb Globe Temperature (WBGT) proposed by the international standard organisation (ISO 7243:2017), only takes into account thresholds based on acclimatization status. Therefore in this study we carried out a PRISMA systematic keyword search of "Wet Bulb Globe Temperature" of the Scopus abstract and citation database in August 2023 and a meta-analysis of text extracted from the identified 913 international studies published between December 1957 and July 2023, to investigate heat stress thresholds for different population groups. We find that different thresholds are considered as an indication of heat stress for different population groups. However, critical gaps were identified for the most vulnerable populations, and there are lower numbers of studies on women. Most studies researched adult populations between the ages of 18 and 55 (n = 491), failing to include the youngest and oldest members of society. Based on these findings, we call for targeted investigations to inform effective heat action policies and set early warning thresholds to ensure the safety and wellbeing of the entire population.
暴露于热的时间随着气候变化而增加。热暴露阈值对于告知热预警系统以及制定工作场所安全的法规和指南非常重要。已经有人指出，由于弱势群体（包括老年人、孕妇、儿童和患有预先存在的医疗条件的人）调节体温或应用冷却策略的能力降低，他们的阈值可能更低。然而，国际标准化组织（ISO 7243:2017）提出的湿球黑球温度（WBGT）仅考虑基于适应状态的阈值。因此，在这项研究中，我们于 2023 年 8 月对 Scopus 摘要和引文数据库中的“湿球黑球温度”进行了 PRISMA 系统关键词搜索，并对 1957 年 12 月至 2023 年 7 月期间发表的 913 项国际研究进行了文本荟萃分析，以调查不同人群的热应激阈值。我们发现，不同的阈值被认为是不同人群热应激的指标。然而，对于最脆弱的人群，存在关键差距，而且针对女性的研究数量较少。大多数研究针对 18 至 55 岁的成年人群（n=491），未能包括社会中最年轻和最年长的成员。基于这些发现，我们呼吁进行有针对性的调查，以告知有效的热行动政策并设定早期预警阈值，以确保全体人口的安全和福祉。
