Eduardo Torroja Construction Sciences Institute (Instituto de Ciencias de la Construcción Eduardo Torroja/IETcc), CSIC, 28033, Madrid.
Climate Change, Health and Urban Environment Reference Unit, Carlos III Institute of Health (Instituto de Salud Carlos III/ISCIII), Madrid, Spain.
Sci Total Environ. 2023 Sep 10;890:164412. doi: 10.1016/j.scitotenv.2023.164412. Epub 2023 May 23.
Urban heat islands (UHIs) have become an especially relevant phenomenon as a consequence of global warming and the growing proportion of people living in cities. The health impacts that are sometimes attributed to the rise in temperature generated in an UHI are not always adequately justified. The objective is to analyse what effect UHIs have on maximum (Tmax) and minimum daily temperatures (Tmin) recorded in urban and non-urban observatories, and quantify the impact on morbidity and mortality during heat waves in Spain's five cities. Data were collected on natural-cause daily mortality and unscheduled emergency hospital admissions (ICD-10: A00-R99) registered in these 5 cities across the period 2014-2018. We analysed daily Tmax and Tmin values at urban and non-urban observatories in these cities, and quantified the impact of Tmax and Tmin values during heat waves in each of these cities, using GLM models that included Tmax only, Tmin only, and both. We controlled for air pollution and other meteorological variables, as well as for seasonalities, trend and the autoregressive nature of the series. The UHI effect was observed in Tmin but not in Tmax, and proved to be greater in coastal cities than in inland and more densely populated cities. The UHI value in relation to the mean Tmin in the summer months ranged from 1.2 °C in Murcia to 4.1 °C in Valencia (difference between urban/non-urban observatories). The modelling process showed that, while a statistically significant association (p < 0.05) was observed in inland cities with Tmax for mortality and hospital admissions in heat waves, in coastal cities the association was obtained with Tmin, and the only impact in this case was the UHI effect on morbidity and mortality. No generalisations can be made about the impact of UHI on morbidity and mortality among the exposed population in cities. Studies on a local scale are called for, since it is local factors that determine whether the UHI effect will have a greater or lesser impact on health during heat-wave events.
城市热岛（UHI）是由于全球变暖以及越来越多的人居住在城市而成为一个特别相关的现象。有时归因于 UHI 产生的温度上升对健康的影响并不总是有充分的依据。本研究旨在分析 UHI 对城市和非城市观测站记录的最高温度（Tmax）和最低日温度（Tmin）的影响，并量化其对西班牙五个城市热浪期间发病率和死亡率的影响。收集了这五个城市在 2014 年至 2018 年期间因自然原因导致的每日死亡率和非计划性急诊入院（ICD-10：A00-R99）的数据。我们分析了这些城市的城市和非城市观测站的每日 Tmax 和 Tmin 值，并使用仅包括 Tmax、仅包括 Tmin 以及同时包括 Tmax 和 Tmin 的 GLM 模型量化了每个城市热浪期间 Tmax 和 Tmin 值的影响。我们控制了空气污染和其他气象变量，以及季节性、趋势和序列的自回归性质。在 Tmin 中观察到 UHI 效应，但在 Tmax 中没有观察到，并且在沿海城市中比在内陆城市和人口更密集的城市中更大。夏季 UHI 值与平均 Tmin 之间的差异范围从穆尔西亚的 1.2°C 到瓦伦西亚的 4.1°C（城市/非城市观测站之间的差异）。建模过程表明，虽然在内陆城市中，Tmax 与热浪期间的死亡率和住院率之间存在统计学上显著的关联（p<0.05），但在沿海城市中，与 Tmin 之间存在关联，并且这种情况下唯一的影响是 UHI 对发病率和死亡率的影响。不能对城市暴露人群中 UHI 对发病率和死亡率的影响进行一般化。需要进行局部规模的研究，因为是局部因素决定了在热浪事件中 UHI 效应对健康的影响会更大还是更小。
