1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T Series K TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Supplement 1 (07/2014) SERIES K: PROTECTION AGAINST INTERFERENCE ITU-T K.91 Guide on electromagnetic fields and health ITU-T K-series Recommendations Supplement 1 K s
2、eries Supplement 1 (07/2014) i Supplement 1 to ITU-T K-series Recommendations ITU-T K.91 Guide on electromagnetic fields and health Summary The objective of Supplement 1 to the ITU-T K-series Recommendations, Guide on electromagnetic fields and health, is to answer questions commonly posed by the pu
3、blic on EMF and to address related concerns. This Guide on electromagnetic fields and health aims to: Provide electromagnetic field (EMF) information and education resources suitable for all communities, stakeholders and governments. Support clarification of the science by referencing the WHO and ot
4、her stakeholders (see Note) that provide information that is particularly useful in helping to clarify scientific uncertainties e.g., in the areas of radio frequency (RF) technology, infrastructure implementation, usage and consequential EMF exposure. NOTE The primary reference on EMF and health is
5、the World Health Organization (WHO). The primary reference on EMF assessment methods is the International Telecommunication Union (ITU) and the International Electrotechnical Commission (IEC). History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T K Suppl. 1 2014-07-29 5 11.1002/10
6、00/12304 _ * To access the Recommendation, type the URL http:/handle.itu.int/ in the address field of your web browser, followed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii K series Supplement 1 (07/2014) FOREWORD The International Telecommunication
7、Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff question
8、s and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on
9、 these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this publication, the exp
10、ression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this publication is voluntary. However, the publication may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability
11、) and compliance with the publication is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the publicat
12、ion is required of any party. INTELLECTUAL PROPERTY RIGHTSITU draws attention to the possibility that the practice or implementation of this publication may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed I
13、ntellectual Property Rights, whether asserted by ITU members or others outside of the publication development process. As of the date of approval of this publication, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this publication. Howe
14、ver, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2015 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the pr
15、ior written permission of ITU. K series Supplement 1 (07/2014) iii Table of Contents Page 1 Introduction to EMF . 1 1.1 The electromagnetic spectrum 1 1.2 What is an electromagnetic field (EMF)? 1 1.3 What is a radio frequency (RF) electromagnetic field? 1 1.4 What is ionizing radiation? . 2 1.5 Wha
16、t is non-ionizing radiation? . 2 2 Overview of EMF and health . 2 2.1 International EMF Project 2 2.2 Information on mobile phones and health 3 2.3 Information on base stations and health . 3 2.4 Information on human exposure guidelines . 3 2.5 Research on EMF and health 4 2.6 Effects of EMF . 4 2.7
17、 International Agency for Research on Cancer 4 3 Mobile phones and base stations 6 3.1 How mobiles and wireless devices work 6 3.2 Towers and antennas 7 3.3 Does the power of a base station vary? 7 3.4 Mobile phone power transmitters . 7 4 Mobile phones and SAR . 8 4.1 What is SAR? . 8 4.2 How SAR v
18、aries . 8 4.3 How important is the SAR value? 9 4.4 How SAR is measured for devices . 10 4.5 Example of SAR test results . 10 4.6 Does SAR vary between mobile phones? 11 4.7 Are low SAR mobile phones safer? . 11 4.8 Finding the SAR for your mobile . 11 5 Relevant EMF guidelines and standards . 11 5.
19、1 Human EMF exposure guidelines 11 5.2 Safety factors 12 5.3 ITU standards and guidelines . 12 5.4 IEC standards 13 5.5 IEEE standards . 13 6 Mobile phones and EMF FAQ . 14 6.1 What are the health risks associated with mobile phones and their base stations? 14 6.2 Do mobile phones emit radiation? 15
20、 iv K series Supplement 1 (07/2014) Page 6.3 How much power does a mobile phone transmit? 15 6.4 How does adaptive power control work? . 15 6.5 Does the EMF from my mobile vary? 15 6.6 What are exposure levels from mobile phones? . 15 6.7 What is the typical power of a mobile phone? . 16 6.8 How can
21、 I reduce exposure from my mobile? 16 6.9 Do mobile phone shields reduce exposure? . 17 6.10 Do mobiles radiate less EMF when close to a base station? 17 6.11 Do mobiles have less EMF when the signal display has full bars? 17 6.12 Does texting have lower exposure compared to calls? . 17 6.13 Are we
22、at a high risk of EMF exposure when using mobile phones inside high speed transportation? 17 6.14 Is using a mobile phone in the car or at home safer because these constitute a barrier to radiation? . 18 6.15 Are children more vulnerable to the EMF from mobile phones than adults? . 18 7 Base station
23、s and EMF FAQ 19 7.1 What are the EMF levels around base stations? . 19 7.2 Is it safe to live near a base station, or to locate base stations near schools? 19 7.3 Do more base stations reduce EMF? 20 7.4 Is it safe to locate base stations on hospitals? . 20 7.5 Are there restricted areas in front o
24、f base station antennas? 20 8 EMF standards FAQ . 20 8.1 Who sets the EMF human exposure standards? . 20 8.2 Is there a safety margin built into the standards? . 20 8.3 Are children and pregnant women protected by the safety standard? 21 8.4 Are people with electronic implants protected by the safet
25、y standard? . 21 9 EMF myths FAQ 21 9.1 Is it possible to cook an egg or grains of corn using a mobile phone? . 21 9.2 Is the power output of a mobile phone enough to make the brain boil? 22 9.3 Does use of a mobile phone attract lightning? . 22 9.4 Can a mobile phone cause a gas station to catch fi
26、re? . 22 10 ITU EMF resources 22 11 Additional EMF resources 22 11.1 WHO resources 22 11.2 ICNIRP resources . 22 11.3 National government resources 23 11.4 Non-government organizations 23 12 About this Guide on electromagnetic fields and health 23 K series Supplement 1 (07/2014) v Page 13 Bibliograp
27、hy . 23 K series Supplement 1 (07/2014) 1 Supplement 1 to ITU-T K-series Recommendations ITU-T K.91 Guide on electromagnetic fields and health 1 Introduction to EMF 1.1 The electromagnetic spectrum Electromagnetic fields have existed in different forms since the birth of the universe. Electromagneti
28、c fields differ from each other in relation to frequency, and visible light is their most familiar form. Electric and magnetic fields are part of the electromagnetic spectrum which extends from static electric and magnetic fields, through radio frequency (RF), infrared radiation and visible light to
29、 X and gamma-rays, see Figure 1. Figure 1 The electromagnetic spectrum 1.2 What is an electromagnetic field (EMF)? An electromagnetic field consists of waves of electric and magnetic energy moving together through space. Often the term “electromagnetic field“ or EMF is used to indicate the presence
30、of electromagnetic radiation. 1.3 What is a radio frequency (RF) electromagnetic field? A part of the electromagnetic spectrum extending from the 3 kHz frequency to 300 GHz is referred as radio frequency (RF). Television and radio transmitters (including base stations) as well as microwaves, mobile
31、telephones and radars produce radio frequency fields. These fields are used to transmit information and form the basis of telecommunications as well as radio and television broadcasting all over the world. Many home devices such as cordless phones, baby monitors and radio-controlled toys also transm
32、it EMF at radio frequencies. 2 K series Supplement 1 (07/2014) 1.4 What is ionizing radiation? Electromagnetic radiation at frequencies above the UV band are classified as “ionizing radiation“, because they have enough energy to effect changes in atoms by liberating electrons (ionizing) and thus alt
33、ering their chemical bonds. X-rays and gamma rays are common forms of ionizing radiation. Ionizing radiation occurs at frequencies above 2900 THz (2900 1012 Hz). This corresponds to a wavelength of about 103.4 nm, which lies near the lower wavelength-edge of the ultraviolet (UV) spectrum. 1.5 What i
34、s non-ionizing radiation? Electromagnetic radiation at frequencies below the UV band are classified as “non-ionizing radiation“ because they lack the energy to liberate electrons i.e., to ionize or effect changes in atomic structure. Radio frequency fields are non-ionizing radiations. 2 Overview of
35、EMF and health 2.1 International EMF Project Wireless communication technology has become an indispensable part of modern society. Mobile phones, tablets and wireless devices have become basic communication tools of everyday life for billions of people around the world and are also common in medical
36、 applications. Base stations and telecommunications towers are continuously being erected to provide good quality wireless communications. Together with the introduction of wireless communication technologies, there has been some degree of public concern about the potential health risks associated w
37、ith wireless communications including the use of mobile phones and living near base stations. Figure 2 Wireless devices in everyday use Electromagnetic fields (EMFs) of all frequencies represent one of the most common and fastest growing environmental influences. As part of its charter to protect pu
38、blic health and in response to public concern, the WHO established the International EMF Project in 1996. The purpose of the International EMF Project is to assess the scientific evidence of possible health effects of EMF in the frequency range from 0 to 300 GHz. Further information on the WHO Inter
39、national EMF Project is available at www.who.int/peh-emf/about/en/ In terms of EMF and health the WHO notes: K series Supplement 1 (07/2014) 3 2.2 Information on mobile phones and health The WHO notes: 2.3 Information on base stations and health The WHO notes: 2.4 Information on human exposure guide
40、lines The WHO notes: “All reviews conducted so far have indicated that exposures below the limits recommended in the ICNIRP (1998) EMF guidelines, covering the full frequency range from 0-300 GHz, do not produce any known adverse health effect. However, there are gaps in knowledge still needing to b
41、e filled before better health risk assessments can be made.“ Source: WHO EMF Research http:/www.who.int/peh-emf/research/en/ and WHO Summary of Health Effects www.who.int/peh-emf/about/WhatisEMF/en/index1.html “A large number of studies have been performed over the last two decades to assess whether
42、 mobile phones pose a potential health risk. To date, no adverse health effects have been established as being caused by mobile phone use.“ “While an increased risk of brain tumours from the use of mobile phones is not established, the increasing use of mobile phones and the lack of data for mobile
43、phone use over time periods longer than 15 years warrant further research of mobile phone use and brain cancer risk. In particular, with the recent popularity of mobile phone use among younger people, and therefore a potentially longer lifetime of exposure, WHO has promoted further research on this
44、group and is currently assessing the health impact of RF fields on all studied endpoints.“ Source: WHO Fact Sheet 193 June 2011 http:/www.who.int/mediacentre/factsheets/fs193/en/ WHO Online Q more data are needed, particularly on longer-term use of mobile phones“. “With regard to environmental expos
45、ures from transmitters, including television, radio, and military transmissions as well as mobile phone networks, the evidence is inadequate due to lack of high-quality studies with accurate individual exposure assessment“. Source: IARC World Cancer Report 2014 http:/www.iarc.fr/en/publications/book
46、s/wcr/wcr-order.php K series Supplement 1 (07/2014) 7 Mobile phone base stations are low-power, multi-channel two-way radios located inside an equipment hut or cabinet. The base station antennas, which transmit and receive the radio signal, can be mounted on transmission towers, poles, roof-mounted
47、structures or in small microcell boxes providing localized coverage. Mobile phone base station radio transmitters typically operate at between 2-50 watts. In rural areas base stations may use additional power amplifiers for the transmitter and receiver to extend coverage. The location and positionin
48、g of the base station antennas are carefully chosen to match the required coverage area. Small base station antennas are often located inside buildings to provide dedicated indoor coverage. 3.2 Towers and antennas It is important to know the difference between antennas and towers. Towers are the str
49、uctures to support the antennas. Like a street light where the brightness depends on distance from the light and not on its support pole. You need to keep your distance from the antennas that transmit the radio signal and not the towers that hold the antennas. You also need to be aware of the many different designs of mobile phone base stations that vary widely in their power and characteristics, affecting their potential for exposing people to RF signals. Research has shown that at
