Assessment of levels of occupational exposure to workers in radiofrequency fields of two television stations in Accra, Ghana

POTENTIAL EXPOSURE LEVELS FROM BROADCAST TRANSMITTERS IN GHANA

The protection of man and his environment from undue exposure from radio frequency electromagnetic field requires identification of the location where exposures are likely to be higher than safe levels established by international safety standards. A wideband measurement with a spectrum analyzer and a log-periodic antenna in conjunction with the three-point spatial average method was used. The results ranged from 16.21 to 2907.00 mVm-1 and complied with a maximum of 1.08% of the ICNIRP reference level. Private frequency modulation (FM) sources were identified as the major source of exposure to the public with a mean value of 337.70 ± 133.70 mVm-1 against 122.30 ± 36.47 mVm-1 for the public FM transmitters. Even though the result was lower than a workplace assessment, it was, however, higher than similar works conducted in Africa and Palestine. Finally, four sensitive locations were identified for further research work.

Assessment of Personal Occupational Exposure to Radiofrequency Electromagnetic Fields in Libraries and Media Libraries, Using Calibrated On-Body Exposimeters

Background and Objectives: With the spread of Wifi networks, safety concerns have arisen, with complaints of somatic disorders, notably in traditional libraries and media libraries. The aim of the present study was to describe the conditions and levels of exposure to radiofrequency electromagnetic fields in the real-life occupational conditions of those working in traditional libraries and media libraries. Methods: Dynamic measurements, using an exposimeter, were taken in 20 radiofrequency bands from 88 to 5850 MHz. The activity of 28 library workers was analyzed on a space-time budget. An audit of exposure sources and static measurements enabled the work-places to be mapped. Results: In seven libraries, 78,858 samples were taken over the 20 radiofrequency bands from 88 to 5850 MHz. Exposure was described for 28 working days. The median total field was 0.071 V/m (10th percentile: 0.022 V/m, 90th percentile: 0.534 V/m) and for Wifi the median field was 0.005 V/m (10th percentile: 0.005 V/m, 90th percentile: 0.028 V/m). Median individual exposure to Wifi frequency waves ranged from 0.005 to 0.040 V/m. Conclusions: Overall, the occupational exposure in this sector was close to the exposure in the general population. Peaks were due to the use of walkie-talkies by security staff. Exposure due to external sources depended on geographic location. Exposure in this occupation is well below the general occupational exposure levels, notably as regards Wifi.