Purpose: This article is a systematic review of studies on the effects of non-ionizing radiation at the microwave (MW) frequency of 2.45 GHz (2450 MHz), which is predominantly used in WLAN/Wi-Fi applications (wireless local area network) and microwave ovens. Newer WLAN standards also use the frequency ranges of 5 GHz, 6 GHz, and 60 GHz. WLAN, referred to generically in this review also as Wi-Fi, has become the technology of choice for many wireless applications because providers do not require a license, making the service free to users. To meet users’ desire to be online all the time, more and more WLAN antennas (access points, femtocells, routers) emitting pulsed 2.45 GHz radiation are being installed at libraries, hospitals, hotels, airports, railway stations, shopping malls, public places, and in buses, subways, and passenger trains. Wi-Fi consoles are used to play games. Office and household appliances are also fitted with Wi-Fi antennas. Residential routers often contain two Wi-Fi transmitters. As part of its digital learning initiative, the German Conference of Ministers of Education has decided to provide all schools with Wi-Fi networks. The extensive body of research on the health risks of Wi-Fi radiation is generally not considered by policy-makers or in the public debate.
Method: For this review, primarily the databases LIVIVO (ZBMED) and PubMed were searched for studies, without limiting the publication date range. The selected studies have all been published in peer-reviewed journals.
Result: More than 100 studies on 2.45 GHz radiation were analyzed, most of which found changes compared to the control groups at levels below the safety guidelines of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) (issued as exposure limits of the 26th Federal Pollution Control Ordinance (BImSchV) in Germany). The available studies document damage to the reproductive system, impacts on the EEG and brain functions, as well as effects on the heart, liver, thyroid, gene expression, cell cycle, cell membranes, bacteria, and plants. As a mechanism of action, many studies identify oxidative stress. Adverse effects on learning, memory, attention, and behavior are the result of cytotoxic effects.
Conclusions: Based on the extensive body of research and the adverse health effects demonstrated in the majority of the studies, it is recommended that steps should be taken to minimize RF radiation exposure in accordance with official recommendations. Wired solutions should be given preference. Current exposure limits and SAR values do not protect from health risks associated with Wi-Fi radiation. The adverse effects on learning, attention, and behavior serve as a basis for educational institutions of all age groups to forgo the use of Wi-Fi applications. Due to cytotoxic effects, Wi-Fi technologies are not suitable for hospitals and telemedicine. Wi-Fi technologies should not be used in bedrooms, work spaces, common lounges, hospital rooms, lecture halls, classrooms, and public transport. The possible risks ssociated with Wi-Fi radiation could be avoided by testing alternative technologies at other frequency bands like optical VLC/Li-Fi technologies (visible light communication). When Wi-Fi cannot be avoided as a transition solution, the ALARA principle must be applied: no continuous transmission, instead Wi-Fi networks that can be turned off and feature dynamic power management.