Assessment of Wi-Fi radiation in indoor environments characterizing the time & space-varying electromagnetic fields

• An exhaustive analysis of Wi-Fi electromagnetic fields is made via a dosimeter.
• Coefficient of variation for the temporal variability up to 29 dB has been found.
• Differences upto 62 dB have been found among the different rooms of the house.
• Web Browsing shows a fluctuating behavior although with lower mean value than P2P.
• With line of sight between transmitter and receiver, levels are non negligible.

This paper focuses on the study of emissions in Wi-Fi networks in a typical indoor place, inside a building, by quantifying exposure levels detected in different locations of the house, when router-terminal devices are in specific positions, and also by characterizing the fluctuations arising from the type of traffic which is sent through the network. The assessment of exposure was carried out collecting measurements with the novel dosimeter ‘EME Spy-140’ in a real scenario and comparing the results with the corresponding theoretical levels and other studies. A global sum of 4875 samples were collected, analyzing 25 locations in the mentioned house. The ROS-MLE method was used for fitting levels to statistical distributions. Maximum background exposure to WLAN (our WiFi network off) is 0.039 V/m. With our WiFi network in operation, maximum exposure increases to 2.6 V/m in the far field region of the transmitters (with 90th percentile of 2.2 V/m). Concerning the type of traffic, oscillations up to 10 dB were detected for exactly the same position, depending on whether Web-browsing or P2P traffic was being sent. Differences around 62 dB in mean values between the different rooms of the house were found. All values are below the threshold of 61 V/m that standards set (at least 12 times below it). Undoubtedly, this type of study is important to raise awareness that radiation coming from this technology is not negligible, and should be controlled, as well as providing an overview of level fluctuations in a given context. This information helps clarify epidemiological studies about exposure levels.