As both the environment and telecommunications networks are inherently dynamic, our exposure to environmental radiofrequency (RF) electromagnetic fields (EMF) at an arbitrary location is not at all constant in time. In this study, more than a year's worth of measurement data collected in a fixed low-cost exposimeter network distributed over an urban environment was analysed and used to build, for the first time, a full spatio-temporal surrogate model of outdoor exposure to downlink Global System for Mobile Communications (GSM) and Universal Mobile Telecommunications System (UMTS) signals. Though no global trend was discovered over the measuring period, the difference in measured exposure between two instances could reach up to 42 dB (a factor 12,000 in power density). Furthermore, it was found that, taking into account the hour and day of the measurement, the accuracy of the surrogate model in the area under study was improved by up to 50% compared to models that neglect the daily temporal variability of the RF signals. However, further study is required to assess the extent to which the results obtained in the considered environment can be extrapolated to other geographic locations.

由于环境和电信网络本质上都是动态的，因此我们在任意位置暴露于环境射频（RF）电磁场（EMF）的时间并非始终恒定。在这项研究中，分析并使用了分布在城市环境中的固定低成本曝光计网络中超过一年的测量数据，并首次建立了室外暴露于下行链路的完整时空替代模型。全球移动通信系统（GSM）和通用移动通信系统（UMTS）信号。尽管在整个测量期间未发现任何全局趋势，但两个实例之间的已测暴露差异可能高达42 dB（功率密度为12,000倍）。此外，还发现，考虑到测量的小时和日期，与忽略RF信号每日时变的模型相比，在研究区域中替代模型的准确性提高了50％。但是，需要进一步的研究来评估在考虑的环境中获得的结果可以外推到其他地理位置的程度。