# 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
Exposure over all frequency bands along the whole week increased by 0.026 mW/m\({}^{2}\) (0.1 V/m) per hour of mobile phone use and by 0.027 mW/m\({}^{2}\) (0.1 V/m) per hour of cordless phone use. In case of mobile phone used by other people in the same environment, exposure to uplink increased by 0.023 mW/m\({}^{2}\) (0.09 V/m) per hour of mobile phone use. The corresponding increase in the DECT band was 0.009 mW/m\({}^{2}\) (0.06 V/m) per hour of cordless phone use. Total exposure calculated without personal phone use increased by 0.010 mW/m\({}^{2}\) (0.06 V/m) per hour of mobile phone use and by 0.013 mW/m\({}^{2}\) (0.07 V/m) per hour of cordless phone use. A more recent study by [PERSON] et al. (2019) focused on the personal measurement of the RF-EMF exposure levels in Swiss adolescents. Even if the focus of the study was not the assessment of the exposure in indoor environments, the authors detailed the levels of exposure recorded in different indoor locations in which the involved subjects spent their time. The participants carried a portable RF-EMF measurement device measuring 13 frequency bands ranging from 470 to 3600 MHz for three consecutive days (with sampling interval equal to 4 s) and kept a time-activity diary. In total, 90 adolescents aged 13 to 17 years participated in the study conducted between May 2013 and April 2014. In addition, personal measurement values were combined with dose calculations for the use of wireless communication devices to quantify the contribution of various RF-EMF sources to the daily RF-EMF dose of adolescents. Results showed that the adolescents' average total personal RF-EMF measurements were highest when spending time in public transport and cars (839.4 \(\upmu\)W/m\({}^{2}\), 0.56 V/min terms of electric field strength, in cars, 676.3 \(\mu\)W/m\({}^{2}\), 0.51 V/m in terms of electric field strength, in buses and 537.1 \(\mu\)W/m\({}^{2}\), 0.45 V/m in terms of electric field strength, in trains), while the lowest measurements were measured at school (59.6 \(\mu\)W/m\({}^{2}\), 0.15 V/m in terms of electric field strength) and at home (31.1 \(\mu\)W/m\({}^{2}\), 0.11 V/m in terms of electric field strength). The main contribution for all the indoor locations was due to uplink signals, while the presence of WLAN at school and at home had little impact on the personal measurements (WLAN accounted for 3.5% of total personal measurements). A very recent study by [PERSON] et al. [77] focused on the assessment of RF-EMF exposure in the Spanish children by spot and personal measurements in the locations where children tend to spend most of their time, i.e., homes, schools and parks, in order to identify which locations and sources contribute most to the level of exposure. 104 eight years children were involved: spot measurements were conducted in homes, schools and their play grounds and parks. At the same time, personal measurements were taken for a subsample of 50 children during 3 days. Results showed that median exposure levels ranged from 29.73 \(\mu\)W/m\({}^{2}\) (0.11 V/m, 0.38% of the ICNIRP reference level) in children's bedrooms to 200.10 \(\mu\)W/m\({}^{2}\) (0.27 V/m, 0.88% of the ICNIRP reference level) in school playgrounds for spot measurements and were higher outdoors than indoors. The sources that contributed most to the exposure were FM radio, mobile phone downlink and Digital Video Broadcasting-Terrestrial, while indoor and personal sources contributed very little. Similar distribution was observed with personal measurements. Two studies by [PERSON] [17; 78], carried out narrowband and broadband measurements in a high number of public indoor environments of different dimensions, including offices, hospitals, commercial locations, hotels and universities, for assessing the exposure due to the WiFi systems.