Exposure of the General Public to Radio Waves near Microcell and Picocell Base Stations for Mobile Telecommunications

Exposures of the general public to radio waves transmitted by microcell and picocell base stations for mobile telecommunications have been assessed through theoretical and experimental means. More generally, exposures to radio waves transmitted over a range of frequencies in the VHF and UHF bands by a variety of sources have also been investigated experimentally. Twenty GSM base stations were selected at random from a group of 3000 that had low antenna height and radiated low power, in accordance with the accepted characteristics of microcell and picocell base stations. A compliance distance in terms of the reference level advised by ICNIRP for exposure of the general public was determined for the antenna of each of the selected base stations, based on technical information provided by the network operators. Under conservative assumptions, the minimum height at which the reference level could potentially be exceeded at any of the sites is 2.4 m above ground level. The power density of the BCCH carrier transmitted by the microcell base station of interest was measured at 610 locations distributed over ten of the twenty base station sites. Most of the measurement locations were outdoors, at heights in the range 0.9–1.7 m above ground level, and were accessible to the general public. Exposure quotients derived from the measured data were generally in the range 0.002–2% and the greatest exposure at any of the sites was 8.6% of the ICNIRP public reference level. The percentage of total exposure contributed by the base station of interest was investigated through spectral measurements at all twenty sites, at a total of sixty measurement locations. The percentage contribution was found to be highly variable and ranged from less than 1% to almost 100% depending on the site and the measurement location. On the basis of the results of the measurements and calculations carried out for the twenty selected microcell base stations, members of the public would not be exposed in excess of the ICNIRP guidelines whilst standing on the ground at any of the sites. Exposures that comply with the guidelines are not considered hazardous.