## 4 Discussion  
Two main approaches were identified in RF-EMF exposure studies: spot measurements and mixed methodologies. Spot measurements involve taking measurements at specific locations during a fixed period of time, while mixed methodologies combine different approaches, such as personal measurements with volunteers, mobile measurements with trained researchers, and prediction models. Spot measurements allow for the intensity of the electromagnetic wave and, therefore, the exposure in specific locations chosen by the researcher. In studies that aim to characterize the signals from RF-EMF, they are widely used because they allow the knowledge of the exposure in a room, a classroom, a work area, or a laboratory environment. Spot measurements are key in research on electromagnetic waves because they help analyze propagation patterns and signal losses within buildings, and they are particularly useful for the study and design of wireless networks. We know that spot measurements have specific limitations, such as fluctuations in the intensity of the RF signal that can vary due to changes in the environment or the influence of other electronic devices. It is known that a spot measurement is not able to capture these temporal variations. There are also limitations with the frequency bands that can lead to obtaining values far from the real ones. A single measurement does not provide us with information on how an RF wave interacts with other variables (people, obstacles, etc.). But these types of measurements help us understand the sophisticated way in which waves interact with the medium in which they travel. If we want to compare the different studies in which RF-EMF exposure measures have been carried out, we realize that it is difficult to make a direct comparison of the results since both the methodologies and the equipment used are different. For this reason, it is necessary to define the objectives of the different studies and, accordingly, determine the  
Figure 8: Equipment used in the studies included in the review. type of study and select the measurement and analysis method, measurement devices, even the microenvironments and the subjects that will participate in the study. As [PERSON] [123] has highlighted in his review, different study protocols could affect the results; for instance, in measurements with volunteers, the body effect could be one of the main factors of underestimation of the exposure, including the use of their electronic devices during the measurement process. In the spot measurements, one of the aspects that could affect the results is, for instance, the inadequate selection of the chosen spatio-temporal points or the measurements recorded below the equipment's detection limit. These types of difficulties can be solved by following the strategies used by other researchers, as specified in each study. Just to highlight some, on the one hand, to avoid the effect on the body, two crosimeters have been used (one on each side of the waist of the study subject) or carrying the exposimeter above the head; and on the other hand, to know the intensity levels at unmeasured points, interpolation methods have been used. We want to highlight the 23 systematic reviews published in this field of study that have also helped us find publications on the RF-EMF [30; 123; 124; 125; 126; 127; 128; 129; 130; 131; 132; 133; 134; 135; 136; 137; 138; 139; 140; 141; 142], reviews cited in the latest review by [PERSON] [30] that is based on the PRISMA guidelines, combining the PECO methodology and the CASPe instrument. We would like to highlight some of the works cited in this review, which were conducted by [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], and [PERSON]. [PERSON] [50] evaluates the in-situ exposure to RF-EMF from base stations of emerging wireless technologies in 311 locations, 68 indoors and 243 outdoors, distributed in three European countries (Belgium, the Netherlands and Sweden) using spectrum analyzers.