## 1 Introduction  
While emerging technologies that use radiofrequency electromagnetic fields (RF-EMF, 100 kHz-300 GHz), particularly in telecommunications, are vital for modern life, there is an increasing consideration of the possible adverse effects on human health and the environment, which may be potentially exacerbated by aggregation of different types of RF-EMF signals. Some concerned citizen groups perceive fifth-generation telecommunication systems (5G; 5G New Radio; 5G NR) as a more significant threat to public health than previous-generation systems. The exposure guidelines and standards issued by the International Commission for Non-Ionizing Radiation Protection (ICNIRP) and the International Committee on Electromagnetic Safety of the Institution of Electrical and Electronic Engineers (ICES-IEEE) are set to prevent the occurrence of such adverse effects. These guidelines are based on comprehensive reviews of the relevant scientific literature, providing exposure reference levels and basic restrictions for workers and the general population; the latter includes an additional safety factor to account for vulnerable groups. Regarding occupational exposures, the European Union (EU) follows the ICNIRP guidelines [1] (Directive 2013/35/EU [2]), which are in force in all Member States. As for exposure to the general public, the EU published a recommendation (1999/519/EC [3]) for exposures to EMF (0 Hz to 300 GHz), with limits derived from the ICNIRP 1998 guidelines [1]. However, due to the non-binding nature of the recommendation and the different types of EU legislation [4], the related policies vary across European countries [5]. In addition, the exposure limits established by the ICNIRP are based on a thermal threshold. However, there is a debate about the adequacy of these limits and the need to include non-thermal effects for which the results are currently inconclusive. The limits are based on solid and conclusive evidence, while non-thermal effects are not conclusive and not widely accepted by the scientific community. Considering all the above, the adoption of new telecommunication technologies such as 5G requires extensive investigations regarding the potential causal effects between RF-EMF and health to address the following needs:  
* Updated appraisal of the scientific evidence regarding possible links between RF-EMF and health effects for (i) the general public, (ii) workers, and (iii) vulnerable groups to aid public authorities in implementing evidence-based policies, risk assessment, and communication. * Quality criteria, standards, and methodologies (i) to assess RF-EMF exposure and health effects, and (ii) for biological investigations fulfilling the 3R (Replace, Reduce, and Refine) standards. * Understanding interaction mechanisms between RF-EMF and biological systems, including combined exposures with other agents and multiple signals. * Adequate scientific communication to improve awareness among authorities, employers, and citizens, counteracting RF-EMF misinformation. The NextGEM project will provide a framework (see Figure 1 for an overview of the NextGEM approach) for generating health-relevant scientific knowledge and data on new scenarios of exposure to RF-EMF in multiple frequency bands (\"NextGEM: Next-Generation Integrated Sensing and Analytical System for Monitoring and Assessing Radiofrequency Electromagnetic Field Exposure and Health\" is a 4-year research and innovation project (1 July 2022-30 June 2026 funded under Horizon Europe GA 101057527, www.nextgem.eu(accessed on 1 March 2023)). A variety of experimental studies will be carried out at different levels of non-thermal exposures to assess the occurrence of potential effects of RF-EMF alone or in combination with other agents during short- and long-term exposures. Based on the literature reviews, including papers published by other consortia and the work carried out in the project, an exploratory risk quantification, in the case of causal effects of RF-EMF alone or in co-exposure, will be performed.