Department of Geography and Planning, Appalachian State University, Boone, NC, USA.
North Carolina Institute for Climate Studies, North Carolina State University, Asheville, NC, USA.
Int J Biometeorol. 2022 Aug;66(8):1665-1681. doi: 10.1007/s00484-022-02309-y. Epub 2022 Jun 27.
Recent studies have characterized individually experienced temperatures or individually experienced heat indices, including new exposure metrics that capture dimensions of exposure intensity, frequency, and duration. Yet, few studies have examined the personal thermal exposure in underrepresented groups, like outdoor workers, and even fewer have assessed corresponding changes in physiologic heat strain. The objective of this paper is to examine a cohort of occupationally exposed grounds and public safety workers (n = 25) to characterize their heat exposure and resulting heat strain. In addition, a secondary aim of this work is to compare individually heat index exposure (IHIE) across exposure metrics, fixed-site in situ weather stations, and raster-derived urban heat island (UHI) measurements in Charleston, SC, a humid coastal climate in the Southeastern USA. A Bland-Altman (BA) analysis was used to assess the level of agreement between the personal IHIE measurements and weather-station heat index (HI) and Urban Heat Island (UHI) measurements. Linear mixed-effect models were used to determine the association between individual risk factors and in situ weather station measurements significantly associated with IHIE measurements. Multivariable stepwise Cox proportional hazard modeling was used to identify the individual and workplace factors associated with time to heat strain in workers. We also examined the non-linear association between heat strain and exposure metrics using generalized additive models. We found significant heterogeneity in IHIE measurements across participants. We observed that time to heat strain was positively associated with a higher IHIE, older age, being male, and among Caucasian workers. Important nonlinear associations between heat strain occurrence and the intensity, frequency, and duration of personal heat metrics were observed. Lastly, our analysis found that IHIE measures were significantly similar for weather station HI, although differences were more pronounced for temperature and relative humidity measurements. Conversely, our IHIE findings were much lower than raster-derived UHI measurements. Real-time monitoring can offer important insights about unfolding temperature-health trends and emerging behaviors during thermal extreme events, which have significant potential to provide situational awareness.
最近的研究已经对个体经历的温度或个体经历的热指数进行了特征描述，包括新的暴露指标，这些指标可以捕捉暴露强度、频率和持续时间的维度。然而，很少有研究关注代表性不足的群体（如户外工作者）的个人热暴露，更少的研究评估相应的生理热应激变化。本文的目的是研究一组职业暴露的场地和公共安全工作者（n=25），以描述他们的热暴露和由此产生的热应激。此外，这项工作的次要目的是比较南卡罗来纳州查尔斯顿（美国东南部潮湿的沿海气候）的个人热指数暴露（IHIE）在暴露指标、固定现场原位气象站和栅格衍生城市热岛（UHI）测量之间的差异。采用 Bland-Altman（BA）分析评估个人 IHIE 测量值与气象站热指数（HI）和城市热岛（UHI）测量值之间的一致性水平。线性混合效应模型用于确定与 IHIE 测量值显著相关的个体风险因素与现场气象站测量值之间的关联。多变量逐步 Cox 比例风险建模用于确定与工人热应激相关的个体和工作场所因素。我们还使用广义加性模型检查了热应激与暴露指标之间的非线性关系。我们发现参与者的 IHIE 测量值存在显著的异质性。我们观察到，热应激的发生与 IHIE 较高、年龄较大、男性和白种人有关。还观察到热应激发生与个人热指标的强度、频率和持续时间之间存在重要的非线性关系。最后，我们的分析发现，尽管温度和相对湿度测量值的差异更为明显，但 IHIE 测量值与气象站 HI 非常相似。相反，我们的 IHIE 结果远低于栅格衍生的 UHI 测量值。实时监测可以提供有关温度-健康趋势和热极端事件期间新兴行为的重要见解，这具有提供情境感知的巨大潜力。
