Karanja Joseph, Vanos Jennifer, Joshi Ankit, Penner Scott, Guzman Gisel E, Connor Dylan S, Rykaczewski Konrad
School of Geographical Sciences and Urban Planning, Arizona State University, Tempe, AZ, 85287-5302, USA.
Urban Climate Research Center, Arizona State University, 975 S Myrtle Ave, Lattie F. Coor Hall, Tempe, AZ, 85281, USA.
Int J Biometeorol. 2024 Aug 26. doi: 10.1007/s00484-024-02751-0.
Concurrent increases in homelessness and heat intensity, duration, and frequency translate to an urban heat risk trap for the unsheltered population. Homelessness is both a driver and consequence of poor health, co-creating distinct geographies with various risk factors that exacerbate heat vulnerability. We tested the efficacy of different tent shadings over identical tents often observed in the Phoenix area (white bedsheet, mylar, tarp, and aluminum foil) and compared them to a control tent (uncovered) and ambient conditions. We monitored all meteorological variables at all six locations, notably Mean Radiant Temperature (MRT). The in-tent microclimate variability was applied to complete statistical and physiological modeling including substance use on heat strain. Findings indicate that tent shadings resulted in significantly lower in-tent MRT during the day (p < 0.05), but exacerbated in-tent thermal risk during the night compared to the control tent and ambient conditions. Furthermore, we found evidence that the temperature metric matters, and using only either MRT or air temperature (T) to assess "heat" could lead to inconsistent conclusions about in-tent microclimate. Interactions between shade types and time significantly amplified in-tent thermal risk. Physiological modeling indicates a higher risk of heat strain (core temperature beyond 40˚C) for people using substances. Decision makers should promote testing different heat intervening strategies toward realizing effective means of protecting human life and preventing heat illnesses. This study illuminates the need for an interdisciplinary approach to studying tents as shelters that considers the total heat load with heat strain modeling.
无家可归者数量的增加与高温强度、持续时间和频率的上升同时出现，这对无庇护人口构成了城市高温风险陷阱。无家可归既是健康状况不佳的一个驱动因素，也是其结果，它与各种风险因素共同形成了独特的地理分布，加剧了人们对高温的脆弱性。我们测试了在凤凰城地区经常看到的相同帐篷上使用不同遮阳材料（白色床单、聚酯薄膜、防水油布和铝箔）的效果，并将其与对照帐篷（无遮盖）和环境条件进行比较。我们在所有六个地点监测了所有气象变量，特别是平均辐射温度（MRT）。帐篷内的微气候变异性被用于完成包括药物使用对热应激影响的统计和生理建模。研究结果表明，白天帐篷遮阳材料使帐篷内的平均辐射温度显著降低（p < 0.05），但与对照帐篷和环境条件相比，夜间却加剧了帐篷内的热风险。此外，我们发现有证据表明温度指标很重要，仅使用平均辐射温度或气温（T）来评估“高温”可能会得出关于帐篷内微气候的不一致结论。遮阳类型和时间之间的相互作用显著放大了帐篷内的热风险。生理建模表明，使用药物的人热应激风险更高（核心温度超过40˚C）。决策者应推动测试不同的热干预策略，以实现保护人类生命和预防热疾病的有效手段。这项研究表明，需要采用跨学科方法来研究作为庇护所的帐篷，通过热应激建模考虑总热负荷。
