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WHO I Electromagnetic fields and public health Page 1 of 4 <br />Media centre <br />nuLab0r' <br />Electromagnetic fields and public health <br />Base stations and wireless technologies <br />Fact sheet N °304 <br />May 2006 <br />Mobile telephony is now commonplace around the world. This wireless <br />technology relies upon an extensive network of fixed antennas, or base <br />stations, relaying information with radiofrequency (RF) signals. Over 1.4 <br />million base stations exist worldwide and the number is increasing <br />significantly with the introduction of third generation technology. <br />Other wireless networks that allow high -speed internet access and <br />services, such as wireless local area networks (WLANs), are also <br />increasingly common in homes, offices, and many public areas (airports, <br />schools, residential and urban areas). As the number of base stations and <br />local wireless networks increases, so does the RF exposure of the <br />population. Recent surveys have shown that the RF exposures from base <br />stations range from 0.002% to 2% of the levels of international exposure <br />guidelines, depending on a variety of factors such as the proximity to the <br />antenna and the surrounding environment. This is lower or comparable to <br />RF exposures from radio or television broadcast transmitters. <br />There has been concern about possible health consequences from <br />exposure to the RF fields produced by wireless technologies. This fact <br />sheet reviews the scientific evidence on the health effects from continuous <br />low -level human exposure to base stations and other local wireless <br />networks. <br />Health concerns <br />A common concern about base station and local wireless network antennas <br />relates to the possible long -term health effects that whole -body exposure to <br />the RF signals may have. To date, the only health effect from RF fields <br />identified in scientific reviews has been related to an increase in body <br />temperature (> 1 °C) from exposure at very high field intensity found only in <br />certain industrial facilities, such as RF heaters. The levels of RF exposure <br />from base stations and wireless networks are so low that the temperature <br />increases are insignificant and do not affect human health. <br />Share Print <br />http: / /www. who. int/ mediacentre /factsheets /fs304 /en /index.html 11/17/2011 <br />5 <br />