Department of Biosciences, Durham University, Durham, UK.
National Malaria Control Programme, Banjul, The Gambia.
Malar J. 2021 Oct 29;20(1):423. doi: 10.1186/s12936-021-03951-4.
In rural sub-Saharan Africa, thatch roofs are being replaced by metal roofs. Metal roofing, however, increases indoor temperatures above human comfort levels, and thus makes it more likely that residents will not use an insecticide-treated bed net (ITN) at night. Whether the colour of a metal roof affects indoor temperature and human comfort was assessed.
Two identical, experimental houses were constructed with metal roofs in rural Gambia. Roof types were: (1) original bare-metal, (2) painted with red oxide primer or (3) white gloss, to reflect solar radiation. Pairwise comparisons were run in six, five-night blocks during the malaria season 2018. Indoor climate was measured in each house and multivariate analysis used to compare indoor temperatures during the day and night.
From 21.00 to 23.59 h, when most residents decide whether to use an ITN or not, the indoor temperature of a house with a bare metal roof was 31.5 °C (95% CI 31.2-31.8 °C), a red roof, 30.3 °C (95% CI 30.0-30.6) and a white roof, 29.8 °C (95% CI 29.4-30.1). During the same period, red-roofed houses were 1.23 °C cooler (95% CI 1.22-1.23) and white roofs 1.74 °C cooler (95% CI 1.70-1.79) than bare-metal roofed houses (p < 0.001). Similar results were found from 00.00 to 06.00 h. Maximum daily temperatures were 0.93 °C lower in a white-roofed house (95% CI 0.10-0.30, p < 0.001), but not a red roof (mean maximum temperature difference = 0.44 °C warmer, 95% CI 0.43-0.45, p = 0.081), compared with the bare-metal roofed houses. Human comfort analysis showed that from 21.00 to 23.59 h houses with white roofs (comfortable for 87% time) were more comfortable than bare-metal roofed houses (comfortable for 13% time; odds ratio = 43.7, 95% CI 27.5-69.5, p < 0.001). The cost of painting a metal roof white is approximately 31-68 USD.
Houses with a white roof were consistently cooler and more comfortable than those with a bare metal roof. Painting the roofs of houses white is a cheap way of making a dwelling more comfortable for the occupants and could potentially increase bed net use in hot humid countries.
在撒哈拉以南非洲农村地区，茅草屋顶正逐渐被金属屋顶所取代。然而，金属屋顶会使室内温度高于人体舒适度，这使得居民在夜间更有可能不使用经过杀虫剂处理的蚊帐（ITN）。本研究旨在评估金属屋顶的颜色是否会影响室内温度和人体舒适度。
在冈比亚农村地区建造了两个具有金属屋顶的相同实验性房屋。屋顶类型为：（1）原始裸露金属，（2）涂有红色氧化物底漆，（3）白色光泽，以反射太阳辐射。在 2018 年疟疾季节期间进行了六次为期五晚的成对比较。在每个房屋内测量室内气候，并使用多变量分析比较白天和夜间的室内温度。
从 21:00 到 23:59，当大多数居民决定是否使用 ITN 时，带有裸露金属屋顶的房屋内温度为 31.5°C（95%CI 31.2-31.8°C），红色屋顶为 30.3°C（95%CI 30.0-30.6°C），白色屋顶为 29.8°C（95%CI 29.4-30.1°C）。在此期间，红色屋顶的房屋比裸露金属屋顶的房屋凉爽 1.23°C（95%CI 1.22-1.23°C），而白色屋顶的房屋则凉爽 1.74°C（95%CI 1.70-1.79°C）（p<0.001）。在 00:00 到 06:00 期间也发现了类似的结果。带有白色屋顶的房屋的最高日温度低 0.93°C（95%CI 0.10-0.30，p<0.001），但红色屋顶的温度没有变化（平均最高温度差为 0.44°C 更暖，95%CI 0.43-0.45，p=0.081）与裸露金属屋顶的房屋相比。人体舒适度分析显示，从 21:00 到 23:59，带有白色屋顶的房屋（87%的时间舒适）比裸露金属屋顶的房屋（舒适时间为 13%；优势比=43.7，95%CI 27.5-69.5，p<0.001）更舒适。将金属屋顶涂成白色的成本约为 31-68 美元。
带有白色屋顶的房屋始终比裸露金属屋顶的房屋凉爽和舒适。将屋顶涂成白色是一种廉价的方法，可以使居住者的住宅更加舒适，并且在炎热潮湿的国家，可能会增加对蚊帐的使用。
