RF PRT1

11.11.2009

1

GEISLAVARNIR RÍKISINS

ICELANDIC RADIATION SAFETY AUTHORITY

Danish National Board of Health (Sundhedsstyrelsen)

Finnish Radiation and Nuclear Safety Authority (Säteilyturvakeskus, STUK)

Icelandic Radiation Safety Authority (Geislavarnir Rikisins)

Norwegian Radiation Protection Authority (Statens strålevern)

Swedish Radiation Safety Authority (Strålsäkerhetsmyndigheten)

EXPOSURE OF THE GENERAL PUBLIC TO

RADIOFREQUENCY ELECTROMAGNETIC FIELDS

- A joint statement from the Nordic Radiation Safety Authorities -

This statement addresses the exposure of the general public to radiofrequency (RF) radiation emitted

continuously by fixed transmitters located in our surroundings. The joint statement regarding mobile

phones issued in 2004 is still valid (Mobile Telephony and Health – A common approach for the

Nordic competent authorities).

Introduction

The introduction of new sources of electromagnetic fields is fast in the Nordic countries due to

technological developments. Radio and TV transmitters have existed throughout the Nordic countries

for more than 70 and 50 years, respectively. The first generation (NMT) of mobile telecommunication

networks were introduced 30 years ago, the second generation (GSM) came 25 years ago and

third generation (UMTS) networks started around 2000 while the public safety radio network has

been (or soon will be) started up in the Nordic countries. In addition, cordless telephones have been

in use for more than 25 years and wireless networks are used in the home, offices and in public areas.

Wireless alarm and baby monitoring systems using radiofrequency signals are also common, as well

as wireless personal identification systems. Bluetooth technology has been adopted for use in many

pc applications such as the wireless mouse and keyboard, as well as in hands-free devices for mobile

phones.

The above are all examples of sources emitting electromagnetic fields in the radiofrequency range

from 10 MHz to 2.5 GHz. The exposure of the general public in the Nordic countries due to these

sources is well below the international recommendations given by International Commission on Non-

Ionizing Radiation Protection (ICNIRP).

RF PRT 2

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3

Electromagnetic hypersensitivity (EHS)

Issues regarding reported cases of electromagnetic hypersensitivity (EHS) are complex and not easily

addressed. According to the World Health Organisation (WHO) there is no scientific basis to link

EHS symptoms to exposure to an electromagnetic field [WHO, 2005]. Therefore, the Nordic

radiation safety authorities regard EHS as a medical issue, which needs to be dealt with by health

authorities, rather than as a radiation safety issue. The symptoms related to EHS can be real and

severe for sufferers, however, and hence it is important to continue studies aimed at achieving a better

understanding of the causes of EHS.

Conclusion

The Nordic authorities agree that there is no scientific evidence for adverse health effects caused by

radiofrequency field strengths in the normal living environment at present. This conclusion concurs

with the opinion of international scientific and advisory bodies listed as references below [ICNIRP,

1998 and 2009; WHO, 2005 and 2006; SCENIHR 2009; SSI`s Independent Expert Group on Electromagnetic

Fields, 2007]. The Nordic authorities therefore at present see no need for a common recommendation

for further actions to reduce these radiofrequency fields.

It is important to note, however, that many of the technologies which use radiofrequency electromagnetic

fields have only been prevalent for less than two decades. It is therefore important to continue

active research on the possible health effects of radiofrequency radiation and reappraisal of the

scientific literature concerning this issue. It is also important to follow developments in exposure

from different sources and the possible health consequences from such development.

The Nordic authorities wish to emphasize the fact that to reduce the total exposure received by the

general public from wireless communication systems, it is necessary to carry out integrated planning

that takes into account radiation emitted both from fixed antennas and hand-held devices such as

mobile phones. Furthermore, in terms of overall public exposure, mobile phones are a much more

significant source of radiofrequency radiation than fixed antennas. If the number of fixed antennas is

reduced, mobile phones will need to use higher power to maintain their connection, thereby the exposure

of the general public may increase.

For further information about this and possible actions to reduce exposure from mobile phones and

other devices, see the web-pages of the national authorities listed below.

References

Mobile Telephony and Health – A common approach for the Nordic competent authorities (Available

at

ICNIRP. 1998. Guidelines for limiting exposure to time-varying electric, magnetic, and electromagnetic

fields (up to 300 GHz). Health Phys 74:494–522. (Available at

http://www.icnirp.de/documents/emfgdl.pdf)

ICNIRP. 2009. ICNIRP Statement on the “Guidelines for Limiting Exposure to Time-Varying Electric,

Magnetic, and Electromagnetic Fields (up to 300 GHz)”. Health Phys 97:257–258. (Available at

http://www.icnirp.de/documents/StatementEMF.pdf)

World Health Organization (WHO). 2005. Fact sheet 296: Electromagnetic fields and public health -

Electromagnetic Hypersensitivity. (Available at

http://www.who.int/mediacentre/factsheets/fs296/en/index.html)http://www.nrpa.no/archive/Internett/div_dokument/IIS/NordicMobile.pdf)

PART3 RF WAVES

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3

Electromagnetic hypersensitivity (EHS)

Issues regarding reported cases of electromagnetic hypersensitivity (EHS) are complex and not easily

addressed. According to the World Health Organisation (WHO) there is no scientific basis to link

EHS symptoms to exposure to an electromagnetic field [WHO, 2005]. Therefore, the Nordic

radiation safety authorities regard EHS as a medical issue, which needs to be dealt with by health

authorities, rather than as a radiation safety issue. The symptoms related to EHS can be real and

severe for sufferers, however, and hence it is important to continue studies aimed at achieving a better

understanding of the causes of EHS.

Conclusion

The Nordic authorities agree that there is no scientific evidence for adverse health effects caused by

radiofrequency field strengths in the normal living environment at present. This conclusion concurs

with the opinion of international scientific and advisory bodies listed as references below [ICNIRP,

1998 and 2009; WHO, 2005 and 2006; SCENIHR 2009; SSI`s Independent Expert Group on Electromagnetic

Fields, 2007]. The Nordic authorities therefore at present see no need for a common recommendation

for further actions to reduce these radiofrequency fields.

It is important to note, however, that many of the technologies which use radiofrequency electromagnetic

fields have only been prevalent for less than two decades. It is therefore important to continue

active research on the possible health effects of radiofrequency radiation and reappraisal of the

scientific literature concerning this issue. It is also important to follow developments in exposure

from different sources and the possible health consequences from such development.

The Nordic authorities wish to emphasize the fact that to reduce the total exposure received by the

general public from wireless communication systems, it is necessary to carry out integrated planning

that takes into account radiation emitted both from fixed antennas and hand-held devices such as

mobile phones. Furthermore, in terms of overall public exposure, mobile phones are a much more

significant source of radiofrequency radiation than fixed antennas. If the number of fixed antennas is

reduced, mobile phones will need to use higher power to maintain their connection, thereby the exposure

of the general public may increase.

For further information about this and possible actions to reduce exposure from mobile phones and

other devices, see the web-pages of the national authorities listed below.

References

Mobile Telephony and Health – A common approach for the Nordic competent authorities (Available

at

ICNIRP. 1998. Guidelines for limiting exposure to time-varying electric, magnetic, and electromagnetic

fields (up to 300 GHz). Health Phys 74:494–522. (Available at

http://www.icnirp.de/documents/emfgdl.pdf)

ICNIRP. 2009. ICNIRP Statement on the “Guidelines for Limiting Exposure to Time-Varying Electric,

Magnetic, and Electromagnetic Fields (up to 300 GHz)”. Health Phys 97:257–258. (Available at

http://www.icnirp.de/documents/StatementEMF.pdf)

World Health Organization (WHO). 2005. Fact sheet 296: Electromagnetic fields and public health -

Electromagnetic Hypersensitivity. (Available at

http://www.who.int/mediacentre/factsheets/fs296/en/index.html)http://www.nrpa.no/archive/Internett/div_dokument/IIS/NordicMobile.pdf)

PART4 RF WAVES

World Health Organization (WHO). 2006. Fact sheet No 304: Electromagnetic fields and public

health. (Available at http://www.who.int/mediacentre/factsheets/fs304/en/index.html)

SCENHIR (The European Commission Scientific Committee on Emerging and Newly Identified

Health Risks) 2009. Health effects of exposure to EMF, European commission 2009. (Available at

http://ec.europa.eu/health/ph_risk/committees/04_scenihr/docs/scenihr_o_022.pdf)

SSI`s independent expert group on Electromagnetic fields. 2007. (Statens strålskyddsinstitut) SSI

Rapport 2008:12. Recent Research on EMF and Health Risks. Fifth Annual Report from SSI`s independent

expert group on Electromagnetic fields. (Available at

http://www.stralsakerhetsmyndigheten.se/Publikationer/Rapport/Stralskydd/2008/200812/)

Further reading:

www.ssm.se

www.stralevernet.no

www.sis.dk

www.gr.is

www.stuk.fi

PART 5 RF WAVES

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ANNEX -

ANNEX:

1

Exposure of the general public to radiofrequency fields

1. Introduction

This document presents typical exposure of the general public to radiofrequency (RF) radiation in

every-day situations. The lists of RF source technologies/devices (see Table 1 & 2) and exposure

scenarios are not complete since there are many applications that can emit radiofrequencies and new

sources appear regularly. It is however unlikely, due to general rules governing the design of radio

systems, that any new technology will cause significantly higher exposures to the general public in

the foreseeable future than the examples introduced here.

Table 1. An overview of the properties of commonly used RF emitting devices that are used close to

the individual. The general public’s exposure limit for local specific absorption rate (SAR

head and trunk regions is 2 W/kg. The limit for occupational exposure (e.g. police radio) is 10 W/kg.

The given values are for maximum exposure i.e. direct contact between RF transmitter and affected

tissue.

*) for the

Technology Related acronyms Frequency

(MHz)

Maximum

(time averaged)

output power (mW)

Maximum

SAR

(W/kg)

GSM 900 900 250 1.4

GSM 1800 (formerly

DCS 1800)

1800 125 1

Mobile phones

UMTS (also 3G) 1950 125

1

WLAN (also WiFi) 2450 100 1

3G 1950

WiMAX 3500 160 1

Wireless internet

terminals of the

computers

(For base stations,

see Table 2)

Flash-OFDM (@450

in Finland)

450 200

0.5

Cordless phones DECT 1900 10

<0.1

Cordless mouses

and keyboards

Bluetooth 2450 1 or 2.5

<0.01

Cordless hands free

sets

Bluetooth 2450 1 or 2.5

<0.01

PMR446 446 500 0.4

DECT 1900 10 0.03

Baby monitors

+ others 27 (typical) 10

<0.01

Professional mobile

radio (police etc.)

TETRA 400 250

(750 also)

1

(3)

† 125 1

*

radiofrequency electromagnetic field. It is defined as the power absorbed per mass of tissue and has units of watts per

kilogram. SAR is usually averaged either over the whole body, or over a smaller sample volume. Recommended

exposure limits are set by the International Commission Non-Ionizing Radiation Protection (ICNIRP).

Specific absorption rate (SAR) is a measure of the rate at which energy is absorbed by the body when exposed to a† also other mobile phone bands, if 3G not available

PART6 RF WAVES

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ANNEX -

2

2. Exposure sources

The exposure to an individual caused by any single RF source is strongly dependent on the distance

between the source and the individual, the source output power and duration of RF transmission.

Therefore, regarding exposure there are two main types of devices; small devices used close to the

individual (hand-held and/or body-worn) and fixed transmitters. Exposure caused by devices used

close to the individual is localised and usually occasional, since RF transmission shuts down while

not in use, though exposure to RF can be near the ICNIRP exposure limits when such devices are in

use. Fixed transmitters often use high output powers and typically transmit RF continuously. Recommended

exposure limits can therefore be exceeded in close proximity to such sources. Fixed

transmitters are, however, usually installed in places where the general public does not have access,

such that the typical exposure caused by fixed transmitters is very low. Table 1 and 2 list some properties

of the most common RF technologies in use.

Table 2. An overview of commonly used fixed radio transmitters including information regarding

frequency and output power

Technology Related acronyms Frequency

range

(MHz)

Typical output

power

Typical power density

mW/m

2

GSM 900 900 < 0.1

GSM 1800 (former

DCS 1800)

1800 < 0.1

Mobile phone

base stations

UMTS (also 3G) 2150

20 W

< 0.1

TV broadcasts

(digital)

DVB-T 500 - 900 15 kW

< 0.01

Voice radio

broadcasts

VHF, FM-radio 87-108 50 kW

< 0.001

WLAN (also WiFi) 2450 100 mW

3G

♠

WiMAX 3500 1 W

Wireless internet

connections

(base stations)

Flash-OFDM

(@450 in Finland)

450 up to 20 W

Cordless phone

(fixed part)

DECT 1900 10 mW (single

phone

system)

Professional

mobile radio

(police etc.)

TETRA 400 up to 100 W

♠

3G is based on regular mobile phone base stations (see above)

2.1 Handheld and body worn devices

The highest output powers of hand-held/ body worn devices (e.g., mobile phones, laptops incorporating

a WLAN card or other wireless network adapter) are typically in the 100–500 mW range. The

output power is therefore relatively low, though a large fraction can be absorbed by the user leading

to exposures of the same order of magnitude as recommended exposure limits for localised exposure

to the general public (

small due to the low output power of such devices. In addition, such devices are typically used onlySAR limit of 2 W/kg). However, average whole-body exposures will always be

PART7 RF WAVES

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ANNEX -

occasionally and transmit RF only when the device is communicating. Moreover, some devices such

as mobile phones automatically decrease output power if possible i.e., in

areas where reception is good. Hence, typical exposure from these devices is lower than the theoretical

maximum; 0.1-0.5 and <0.01 of maximum values for GSM and 3G, respectively. Exposure

caused by small-range devices (e.g., cordless DECT phones, Bluetooth devices etc.) is typically only

a few percent of exposure limits.

Exposure to RF caused by a small-size low power transmitter generally decreases rapidly with increasing

distance from the source. A 30 cm gap between the receiving body and the transmitter typically

decreases exposure by a factor 100 when compared to direct contact exposure. Therefore, exposure

concerns mainly the user of the device. The individual exposure from such sources is reduced by

increasing the distance between user and device. This can be easily done by e.g., using hands-free for

voice calls and/or placing baby monitors, WLAN terminals etc such that they are not touching the

individual.

3

2.2. Fixed transmitters

Numerous technologies utilise fixed RF transmitters. Signals from WLAN, WiMAX and mobile

phone networks are transmitted by base stations, while TV and voice radio broadcasts are sent via

fixed transmitter antennas in high masts. Transmission powers in these devices range from milliwatt

(mW) to kilowatts (kW).

The antennas transmitting at the highest power levels (kilowatt-range) are the mast-mounted TV and

VHF voice radio transmitters. Power densities measured at ground level are low, however, since the

antennas are mounted 100–300 m above ground. The main RF transmission beam is targeted towards

the horizon; hence virtually all the RF power surpass people living in the vicinity of the mast (see

Fig. 1). Measurements performed around typical broadcasting masts have shown that the field

strengths depend more on the terrain (by factor 1000) than on the distance from the source. The highest

measured values in a normal living environment have been approximately 0.1 mW/m

to measurements in the Nordic countries, though more typical values are between 0.0001 –

0.001 mW/m

due to a lower transmission power being necessary for a single TV program. However, the

number of TV channels will increase and presumably all former frequencies of analogous TV will be

utilised again for digital broadcasts at some time in the future leading to background RF fields being

in the same order of magnitude as before the digitalisation.

2, according2. The introduction of digital TV broadcasting appears to have decreased overall exposure,

Fig.1. Radiowaves from mast-mounted antennas surpasses the people living in the vicinity of the

mast.

RF ANTENNAS!

11.11.2009

ANNEX -

The largest mobile phone base-stations transmit at approximately 100 W (rms

mounted on masts. Lower power levels are used in the antennas that are mounted on roof tops/ building

walls (typically 1-20 W). The main transmission RF beams are narrow in the vertical crosssection

and targeted towards the horizon or some degrees below it. Hence, they are not transmitting

directly towards people living underneath or in the vicinity of the source (as in Fig. 1). Contractors

are instructed to install base-stations in places inaccessible from e.g., ventilation windows or balconies.

Moreover, high power RF antennas should not be pointed directly towards any neighbouring

house, even though the safety distance in the main beam is only a few meters. If these precaution

measures are followed, the exposure to the general public caused by such base-stations is very low.

Measurements have been conducted in upper floor apartments with base-station antenna either directly

above or on the roof of a neighbouring house: typical power densities have been 0.1–10

mW/m

power densities at street level have been lower, typically well below 0.1 mW/m

given in ICNIRP recommendation is 4 500–10 000 mW/m

The TV- and radio broadcasts as well as GSM base-station networks cover most areas of the Nordic

countries. According to measurement campaigns, these technologies produce the highest background

RF fields in the environment. However, measured values are still typically only 1/10000–1/1000 of

the reference levels for power density given in the ICNIRP exposure limits. Many other technologies,

such as TETRA base-stations might cause power densities that are in order of magnitude of 1/10000

of the reference levels, but only present in the proximity of such source. As the exposure level decreases

rapidly with increasing distance from the source, the exposure caused by small transmitters,

such as WLAN base stations, falls below the GSM base-station level if the distance is approximately

more than a meter, such that peoples overall exposure does not increase.

The rapid decrease in exposure from RF with increasing distance from the source also leads to the

fact that exposure from multiple sources seldom increases the overall exposure when compared to

exposure from one or two nearby sources. Moreover, old technologies such as AM-radio or analogous

TV broadcasts have been replaced by technologies capable of significantly more efficient use of

the radio spectrum. Therefore, the fast development of technologies utilising radio waves has not

lead to a similar fast increase of the exposure of the general public; indeed, according to a Swedish

measurement campaign the “background” RF field level has remained the same in the period 2001-

2007.

In addition to the radio transmitters mentioned here, there exist a large number of short range devices,

such as RFID (radio frequency identification) electronic article surveillance gates in e.g. libraries,

car keys, wireless thermometers and alarm systems in shops. The power output of these devices

is small and hence the additional exposure is expected to be very low. Various high power applications

such as radars and satellite links also exist, though according to measurement campaigns and

risk assessment studies (e.g. Mulige helseeffekter av yrkesmessig strålingseksponering fra radar,

2007; Riks-Radiumhospitalet HF 05.07)) these do not cause significant exposure to the general public

under normal conditions.

More information about background RF fields and exposure of the general public is available on the

internet sites of the Nordic radiation safety authorities. The data presented in this document is mainly

based on the results of a Swedish background field measurement campaign (reported in SSI rapport

2008:13) and a Finnish study (reported in STUK-TR 5 2008 in Finnish). Both reports are available

on the web.4*) and they are also2 with measured maximums in individual cases up to 50–250 mW/m2. Measured outdoor2. The reference value2, depending on the frequency.