To study the potential impact of radiofrequency electromagnetic fields of transmitters on the sleep quality of nearby residents, a new study design is presented. In a double-blind crossover field study the effect of on-site shielding, rather than of additional exposure, is examined.
80 MHz–2.5 GHz
Exposure duration: repeated exposure for up to 13 nights
|Setup||The experiments were performed in double-blind random order under screened, sham and control conditions. Screening of about 15 dB was achieved using an RF-absorbing netting which was wrapped on a cubic holder around the bed and also laid on the floor. Sham conditions were implemented using a fabric which could not be distinguished from the screening material.|
|Additional info||The major field contributions (about 70%) came from FM broadcast and GSM base stations. FM broadcast exceeded GSM immissions by factors of 3.2 and 16.2 in two cases, while in the third case both immissions were of roughly the same intensity. Exposure varied considerably through the night (38%) as well as between nights (65%); this variation may be greater than the GSM contribution itself.|
No parameters are specified for this exposure.
Radiofrequency measurement showed that exposure may vary considerably throughout the night, as well as from one night to the next. This variation may be greater than the GSM (Global System for Mobile Communications) contribution itself. Mostly, the contributions of USW radio frequency fields dominated compared to GSM. Thus, continuous broadband radiofrequency recording is required for reliable interpretation of the data. The findings show that simple sleep monitoring systems based on single-channel EEG analysis without access to original biosignals are not adequate for sleep studies.