# RF Exposure Assessment by Drone-Based Technology
###### Abstract  
There is growing international interest in assessing population exposure to radiofrequency electromagnetic fields, especially those generated by mobile-phone base stations. The work presented here is an experimental study in which we assess exposure to radiofrequency electromagnetic fields in a university environment, where there is a site with mobile-phone antennas and where a large number of people live on a daily basis. The data were collected with a personal exposure meter in two samplings, one walking at ground level and the other using an aerial vehicle at a height higher than the buildings. The geo-referenced electric-field data were subjected to a process in which a theoretical model was adjusted to the experimental variograms, and heat maps were obtained using kriging interpolation. The research carried out is of great relevance, since it provides detailed measurements of the electromagnetic radiation levels both at ground level and at significant heights, using innovative methodologies such as the use of drones. Furthermore, the results obtained allow for contextualizing the exposures in relation to international safety limits, highlighting the importance of rigorous monitoring in everyday environments. mobile base stations; environmental electromagnetic fields; exposure assessment; international standards; personal exposure meter; drone-based measurement; variogram fitting; kriging interpolation; heat maps +
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There are numerous instruments and measurement procedures for assessing human exposure to electromagnetic fields. Personal exposimeters (PEMs) have proven to be valuable tools in measuring individual exposure to RF radiation. These portable devices allow researchers to collect real-time data on electromagnetic field levels across multiple frequency bands. Initially, in personal dosimetry studies, PEMs were used attached to the body [2; 3; 4]. Recently, it has become possible to characterize exposure to electromagnetic fields in different micro-environments using vehicles, such as bicycles, cars, and drones [5; 6; 7; 8; 9]. However, PEM devices typically generate vast amounts of data, as they capture measurements in several frequency bands every few seconds. This wealth of information can complicate the analysis, as not all frequency bands provide meaningful data above the device's detection threshold. To manage this, studies often focus on specific frequency bands that are relevant to the environment being studied, such as the frequencies used by nearby mobile base stations. Although many studies have been carried out in different urban settings [6; 10], few have been conducted in university areas [11; 12; 13]. The study we present here aims to assess the electric-field levels generated by a site with a mobile-phone base station located at the Polytechnic School of the University of Extremadura in Caceres (Spain). The presence of mobile-phone antennas is expected to cause high levels of exposure to students, teachers and administrative and service staff, about 2500, who usually live there. We focused on bands commonly used by mobile networks for communication, and are essential in evaluating the exposure levels generated by mobile base stations. The findings will be compared to international safety guidelines to determine whether the measured levels fall within the recommended limits, ensuring the safety and well-being of individuals living or working near mobile base stations. Given the environmental conditions of the study area, such as the presence of buildings and trees, it is expected that the electric-field levels will vary significantly between ground level and elevated heights. Previous research has indicated that exposure tends to increase with height [8; 9] due to the height of the antenna above the ground and fewer obstructions between the measuring device and the source of radiation.