# Radio Frequency Electromagnetic Fields Exposure Assessment in Indoor Environments: A Review
## 3 Results
### Educational Buildings
#### 3.4.4 Comparison between Different Types of Indoor Environments
Results showed that median exposures in terms of power density were highest while children were outside (157.0 uW/m\({}^{2}\), or 0.24 V/m, in terms of electric field strength, 0.86% of the ICNIRP reference level) or traveling (171.3 uW/m\({}^{2}\), or 0.24 V/m, in terms of electric field strength, 0.9% of the ICNIRP reference level), and much lower when children were indoor, at home (33.0 uW/m\({}^{2}\) or 0.1 V/m, in terms of electric field strength, 0.4% of the ICNIRP reference level) or at school (35.1 uW/m\({}^{2}\) or 0.11 V/m, in terms of electric field strength, 0.4% of the ICNIRP reference level). The main contributions to the indoor exposure were found to be due to the downlink and broadcast sources. A similar study by [PERSON] et al. (2019) examined the levels of exposure and the influence of different RF-EMF sources in a sample of 166 volunteers living in a Swiss city by using personal exposimeters. Participants carried an exposimeter for 1 week and completed an activity diary. Mean values were calculated using the robust regression on order statistics (ROS) method. The highest mean values of exposure were recorded for train journeys (1.16 mW/m\({}^{2}\), 0.66 V/m), stays at the airport (0.74 mW/m\({}^{2}\), 0.53 V/m) and rides on the tramway or bus (0.36 mW/m\({}^{2}\), 0.37 V/m), while the smallest levels of exposure were measured in school buildings and kindergartens (0.02 mW/m\({}^{2}\), 0.09 V/m), churches, cinemas and theatres (0.06 mW/m\({}^{2}\), 0.15 V/m). In all locations, mobile telecommunication (up- and downlink) was the main source of exposure. Mobile phone base stations (downlink) were the most important contributor in churches (70.2%), in school buildings and kindergartens (56.0%), outdoor (52.6%) and at home (42.6%). In all other places, exposure was mainly due to mobile phones (uplink) (airport 95.2%; train 93.5%; cinema, etc., 82.8%; sports hall 79.1%; car 78.5%; tramway, bus 73.5%; hospital, doctor 69.0%; university, technical college 68.3%; restaurant, etc., 65.1%; shopping 60.2%; friends place, leisure residence 43.6%; workplace 29.0%). With respect to exposure in public transport, mobile phone uplink exposure was higher for persons using the mobile phone compared to people just exposed to the EMF generated by other user's mobile phones (1.11 vs. 0.87 mW/m\({}^{2}\) in trains and 0.27 vs. 0.23 mW/m\({}^{2}\) in tramways and buses). Contributions from DECT were relevant at home (32.6%), at the workplace (24.1%). The contributions of FM radio and television (TV) broadcast transmitters were relatively small in all the indoor locations. Mobile phone uplink measurements during a call with a mobile phone were on average 4.87 mW/m\({}^{2}\) (1.36 V/m, 3.5% of the ICNIRP reference level) and DECT measurements during a cordless phone call were equal to 2.98 mW/m\({}^{2}\) (1.06 V/m, 2.7% of the ICNIRP reference level). Another study by the same authors ([PERSON] et al., 2018) focused on the impact of personal phone use on personal exposimeter readings. The authors collected both personal exposimeter measurements during one week and spot measurements in the participants' bedrooms. The mean personal exposure, obtained by averaging the results obtained during the whole week, was equal to 0.13 mW/m\({}^{2}\) (0.22 V/m, 0.79% of the ICNIRP reference level), when measurements during personal phone calls were excluded and 0.15 mW/m\({}^{2}\) (0.24 V/m, 0.85% of the ICNIRP reference level), when such measurements were included, while the mean level of exposure observed in the bedrooms of the involved subjects was equal to 0.11 mW/m\({}^{2}\) (0.2 V/m, 0.73% of the ICNIRP reference level). Mean personal exposure in uplink frequency band calculated during the whole week of measurements increased by 0.038 mW/m\({}^{2}\) (0.12 V/m) per hour of mobile phone use, while, as to the DECT frequency band, the mean exposure increased by 0.023 mW/m\({}^{2}\) (0.09 V/m) per hour of cordless phone use.