Heat exposure of a population is often estimated by applying temperatures from outdoor monitoring stations. However, this can lead to exposure misclassification if residents do not live close to the monitoring station and temperature varies over small spatial scales due to land use/built environment variability, or if residents generally spend more time indoors than outdoors. Here, we compare summertime temperatures measured inside 145 homes in low-income households in Baltimore city with temperatures from the National Weather Service weather station in Baltimore. There is a large variation in indoor temperatures, with daily-mean indoor temperatures varying from 10 °C lower to 10 °C higher than outdoor temperatures. Furthermore, there is only a weak association between the indoor and outdoor temperatures across all houses, indicating that the outdoor temperature is not a good predictor of the indoor temperature for the residences sampled. It is shown that much of the variation is due to differences in the availability of air conditioning (AC). Houses with central AC are generally cooler than outdoors (median difference of − 3.4 °C) while those with no AC are generally warmer (median difference of 1.4 °C). For the collection of houses with central or room AC, there is essentially no relationship between indoor and outdoor temperatures, but for the subset of houses with no AC, there is a weak relationship (correlation coefficient of 0.36). The results presented here suggest future epidemiological studies of indoor exposure to heat would benefit from information on the availability of AC within the population.

中文翻译：

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巴尔的摩室内热暴露：室外温度重要吗？

通常通过应用室外监测站的温度来估计人口的热暴露。然而，如果居民不住在监测站附近，并且由于土地利用/建筑环境的变化，温度在小空间尺度上变化，或者如果居民通常在室内的时间比在室外的时间多，这可能导致暴露错误分类。在这里，我们将巴尔的摩市 145 户低收入家庭的夏季温度与巴尔的摩国家气象局气象站的温度进行比较。室内温度变化很大，每日平均室内温度比室外温度低 10°C 到高 10°C。此外，所有房屋的室内和室外温度之间只有微弱的关联，表明室外温度不能很好地预测采样住宅的室内温度。结果表明，大部分变化是由于空调 (AC) 的可用性差异造成的。有中央空调的房子通常比室外凉爽（中值差为 − 3.4 °C），而没有空调的房子通常更暖和（中值差为 1.4 °C）。对于有中央或房间空调的房屋集合，室内和室外温度之间基本上没有关系，但对于没有空调的房屋子集，关系较弱（相关系数为0.36）。此处提供的结果表明，未来对室内高温暴露的流行病学研究将受益于有关人群中空调可用性的信息。