Workshop "Acute Health Impairment", Dec 12-13, 2006
Exposure of the general public to RF electromagnetic fields
Dr. Christian Bornkessel, IMST GmbH, Carl-Friedrich-Gauss-St. 2, D-47475 Kamp-Lintfort [email protected]
IMST GmbH Carl-Friedrich-Gauß-Strasse 2 Tel.: +49-2842-981-0 47475 Kamp-Lintfort Fax: +49-2842-981-199 www.imst.de E-Mail: [email protected] Outline
• RF sources and their exposure - relevant exposures in everyday life - focus on general public exposure - exposure results with special regard to DMF studies
• Personal exposure meters (Dosimeter) - available dosimeters - typical results
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Exposure of general public, November 07 Classification of relevant RF sources
Installation type
Fixed Mobile
Mobile phone Mobile phones base stations TV broadcast DECT phones transmitters Radio broadcast WLAN applications transmitters
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Exposure of general public, November 07 Classification of relevant RF sources
Installation place
Outdoor Household
Mobile phone Mobile phones base stations TV broadcast DECT phones transmitters Radio broadcast WLAN applications transmitters
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Exposure of general public, November 07 Classification of relevant RF sources
Distance
Close to body Far field or body contact Mobile phone Mobile phones base stations TV broadcast DECT phones transmitters Radio broadcast WLAN applications transmitters
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Exposure of general public, November 07 Mobile phone base stations
Frequency: - 925 – 960 MHz (GSM 900) - 1820 – 1880 MHz (GSM 1800) - 2110 – 2170 MHz (UMTS)
Transmit - typ. 5-30 W/channel/sector Power: - 100-1800 W (EIRP)/channel/sector
Transmitter:- ~85,000 stations in Germany
Coverage: - 500 m – 20 km
Distance to Persons: - far field
Remarks: - power control
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Exposure of general public, November 07 Projects supported within DMF Development of measurement and calculation methods for the determination of the public exposure due to electromagnetic fields in the vicinity of mobile phone base stations (IMST)
Determination of the exposure of groups of people that will be investigated within the scope of the project "Cross sectional study for ascertainment and assessment of possible adverse effects by fields of mobile phone base stations" (ECOLOG)
Determination of the real field distribution from BS high frequency electromagnetic fields near UMTS transmitters (IMST+EM Institute)
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Exposure of general public, November 07 Extrapolated exposure (IMST+EM-Institute)
100,000
1.6 % limit GSM 5.4 V/m 10,000 0.7 % limit UMTS 78.3 mW/m² 5.1 V/m 69.3 mW/m²
1,000
0,100
0,010 power density in % of limit
0,001
0,000 1 2 3 4 5 6 7 8 9 1011 0.000001 % scenario no. 0.000001 % 0.004 V/m 0.01 V/m 0.03 µW/m² 0.1 µW/m²
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Exposure of general public, November 07 Extrapolated exposure near base stations (2)
100,000 high mounted antennas GSM 10,000 UMTS
1,000
0,100
0,010 power density in % of limit
0,001
0,000 1 2 3 4 5 6 7 8 9 1011 scenario no.
low mounted antennas low mounted antennas (micro cell / indoor scenarios) Folie 9
Exposure of general public, November 07 Comparison GSM/UMTS
14
GSM UMTS 12
10 Z GSM > UMTS at
8 85 % of all points (compared to limit) 6
electric field strength [% of limit] of [% strength field electric 4
2
0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 3.10 3.11 3.22 3.13 3.14 3.15 3.16 3.17 2.10 2.11 2.12 1.10 1.11 1.12 1.13 1.14 1.15 1.16 1.17 1.18 1.19 1.20 1.21 1.22 measurement point no.
GSM 900 antenna pattern UMTS antenna pattern Folie 10
Exposure of general public, November 07 Small scale field variation in space
Measurement: GSM 900 and UMTS Simulation: GSM 900
100
95
90
85
80
electric field strength [dBµV/m] strength field electric 75 GSM 900 UMTS 70 0 20 40 60 80 100 120 140 place [cm]
• Small scale variations (fast fading) especially at indoor scenarios due to multipath propagation • Variations of 10 dB and more
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Exposure of general public, November 07 Small and large scale variations in time
Station A: GSM 24 hours Station B: GSM 7 days
4 2.0
3,5 1.8 3 1.6 2,5 1.4 2
1,5 1.2 electric field [V/m] strength electric field [V/m] strength 1 1.0 12:00 16:00 20:00 0:00 4:00 8:00 12:00 Tu We Th Fr Sa Su Mo Tu time day
• Small and large scale variations due to traffic load (power control)
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Exposure of general public, November 07 Time and space averaged exposure (ECOLOG)
Exposure inside buildings 1 m x 1 m grid
5 point grid
• Time and space averaging, no focus on "maximal exposed areas" Z Exposure 10 - 1,000 times smaller than measured under worst case aspects
Folie 13 Source: ECOLOG Institute Exposure of general public, November 07 Mobile phones
Frequency: - 880 – 915 MHz (GSM 900) - 1710 – 1785 MHz (GSM 1800) - 1920 – 1980 MHz (UMTS)
Transmit - up to 250 mW time averaged Power: - up to 2 W peak
Number: - ~80 million
Coverage: - up to 20 km
Distance to Persons: - body contact Source: www.sonyericsson.com Remarks: - power control
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Exposure of general public, November 07 SAR-Measurements
2 1,8 1,6 1,4 1,2 1 0,8 0,6 0,4 SAR SAR value 10g [W/kg] 0,2 0 LG LG U8290 Nokia N93 Nokia E50 Nokia N73 Nokia Nokia 3250 Nokia Nokia 6233 Nokia 6270 Nokia 6131 Nokia Nokia 6125 Nokia 6230i Motorola Motorola L7 Motorola Motorola V3x Siemens S75 Palm 650 Treo Motorola Motorola ROKR Sagem my 700X Pantech GU-1100 BenQ-Siemens C81 Samsung SGH-X700 Samsung SGH-E770 Sony Ericsson K750i Sony Ericsson K510i BenQ-Siemens EF81 Sony Ericsson W550i Sony Ericsson W700i Sony Ericsson W810i Sony Ericsson W800i Mobile phone
• SAR is measured under "worst case" conditions (maximal transmit power) • typ. 10 – 75 % limit consumption
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Exposure of general public, November 07 Projects supported within DMF
Determination of the specific absorption rate (SAR values) occurring during day- to-day mobile phone use (Telecom-Consult)
Determination of the real exposure from using mobile phones in partially shielded rooms as compared to exposure under optimal conditions outdoors (Telecom-Consult)
Folie 16 Source: Telecom-Consult Exposure of general public, November 07 Exposure results: Averaged exposure
Inside a room, Nokia 6150 Inside a train, Nokia 6110/6150
Position change
• On average 10 – 50 % of "worst case" SAR, depending on coverage and cell changes • Further reduction due to DTX
Folie 17 Source: Telecom-Consult Exposure of general public, November 07 TV Broadcast
Frequency: - 47 – 68 MHz (analogue) - 174 – 223 MHz (analogue, digital) - 470 – 790 MHz (analogue, digital) - 790 – 862 MHz (digital)
Transmit - up to several 100 kW (ERP) Power: per site
Transmitter:- typ. 5-15 main transmitters each federal state (Germany)
Coverage: - up to 60 km
Distance to Persons: - far field Wendelstein
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Exposure of general public, November 07 Projects supported within DMF
Determination of exposure to the population living near digital radio and television transmitters (IMST+EM Institute)
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Exposure of general public, November 07 Exposure to Analogue TV and DVB-T (same region)
Analogue TV DVB-T
100 100
10 10
1 1
0,1 0,1
0,01 0,01
0,001 0,001
0,0001 0,0001 power power density [% of limit] power density [% of limit]
0,00001 0,00001
0,000001 0,000001 0 50 100 150 200 250 300 350 0 50 100 150 200 250 300 350 measurement point measurement point
• More than 300 measurement points in Nuremberg and Munich region • Points statistically distributed; proportional to population density • Measurements before (A-TV) and after (DVB-T) switching to DVB-T Z Exposures mostly below 0.01 – 0.1 % of limit
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Exposure of general public, November 07 FM radio and DAB
Frequency: - 88 – 108 MHz (FM radio) - 174 – 223 MHz (DAB) - 1452 – 1492 MHz (DAB)
Transmit - FM: typ. several 10 kW (ERP) Power: DAB: typ. several kW per site
Transmitter:- several 100 (Germany)
Coverage: - up to 60 km
Distance to Persons: - far field
www.zinsik.de
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Exposure of general public, November 07 Projects supported within DMF
Determination of exposure to the population living near Hamburg
digital radio and television Berlin transmitters (IMST+EM Institute) Düsseldorf
Stuttgart
München
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Exposure of general public, November 07 Exposure to FM radio and DAB (same region)
FM radio DAB
100 100
10 10
1 1
0,1 0,1
0,01 0,01
0,001 0,001
0,0001 0,0001 power power density [% of limit] power density [% of limit]
0,00001 0,00001
0,000001 0,000001 0 50 100 150 200 250 300 0 50 100 150 200 250 300 measurement point measurement point
• 300 measurement points in Nuremberg and Munich region • Points statistically distributed; proportional to population density Z Exposures mostly below 0.01 – 0.1 % of limit Z DAB exhibits ~11 dB lower exposure compared to FM radio (median)
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Exposure of general public, November 07 Long/Medium/Shortwave radio services
Frequency: - 148 – 255 kHz (LW) - 0.526 – 1.6 MHz (MW) - 3.4 – 26 MHz (SW)
Transmit - several 100 kW per site Power: (up to 2 MW)
Transmitter:- several 10 (Germany)
Coverage: - several 100 km
Distance to Persons: - far field
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Exposure of general public, November 07 Exposure results Study by Wuschek et al., 2003 "Large area measurement of radio waves in Baden-Wurttemberg"
100
10 .
1
0,1
0,01 (electric field strength)² [% of limit])²
0,001
0,0001 1001 1052 1106 1156 2041 2092 2142 2193 2243 2293 2343 2393 2443 2493 2543 3014 3064 4037 measurement point • 895 points, regular 2 x 2 km grid, outdoor Z Exposure may reach or exceed GSM/UMTS exposure near to base stations!
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Exposure of general public, November 07 Wireless LAN (IEEE 802.11b)
Frequency: - 2400 – 2483.5 MHz
Transmit power: - max. 100 mW EIRP
Transmitter:- several 100,000
Coverage: - several 10 meter
Distance to - access points: far field Persons: - mobile: close to body or body contact
Remarks: - power control by duty cycle
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Exposure of general public, November 07 Projects supported within DMF
Determination of human exposure caused by indoor wireless communication technologies applied in homes and offices (ARC Seibersdorf Research)
Determination the real field distribution of high frequency electromagnetic fields near wireless LAN installations (WLAN) in inner cities (ARC Seibersdorf Research)
Folie 27 Source: ARC Seibersdorf Research Exposure of general public, November 07 Exposure results (time and space averaged)
0.1 power density [% of limit] of [% density power
0.01
0.001
0.0001 power density [mW/m²]
0.00001
distance [m]
• outdoor scenarios: typ. 10 -11 – 0.001 % • indoor scenarios: up to 0.1 % • close to body operation: typ. 2 - 3 % of SAR-limit
Folie 28 Source: ARC Seibersdorf Research Exposure of general public, November 07 Digital cordless phones: DECT
Frequency: - 1880 - 1900 MHz
Transmit power: - max. 250 mW peak power
Transmitter:- several 100,000
Coverage: - several 10 meter
Distance to - base station: far field Persons: - mobile: body contact
Remarks: - power control by duty cycle
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Exposure of general public, November 07 Projects supported within DMF
Determination of human exposure caused by indoor wireless communication technologies applied in homes and offices (ARC Seibersdorf Research)
Results: time and space averaged in % of limit • 2 DECT devices, 1 and 3 m: BS: 0.004 – 0.03 %, MS: 0.0002 – 0.004 %
• SAR 10g : 0.6 – 8 % • generic scenarios: 0.00007 – 0.0003 % • mixed scenarios: 0.00007 – 0.023 %
Folie 30 Source: ARC Seibersdorf Research Exposure of general public, November 07 Putting all results together ...
100
body contact 10
1 close to body
0,1
0,01
0,001
0,0001
limit consumption [% of power limit] 0,00001
0,000001 DAB DECT WLAN DVB-T FM radio LMS radio averaged life case analogue analogue TV base base stations mobile phones (SAR) (SAR) worst case radio service base base stations worst mobile daily phones
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Exposure of general public, November 07 ... the same with median
100
body contact 10
1 close to body
0,1
0,01
indoor 0,001
0,0001
limit consumption [% of power limit] 0,00001
outdoor 0,000001 DAB DECT WLAN DVB-T FM radio LMS radio averaged life case analogue analogue TV base base stations mobile phones (SAR) (SAR) worst case radio service median base base stations worst mobile daily phones
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Exposure of general public, November 07 Be carefully with your interpretation!!! Personal exposure meters (Dosimeters)
Maschek ESM-140 Antennessa EME Spy 120
www.maschek.de
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Exposure of general public, November 07 Frequency bands Antennessa UMTS Rx UMTS Rx DCS Rx UMTS Rx DCS Rx DCS RX GSM Rx GSM Rx GSM Rx WIFI TV3 Tetra TV4&5 DECT FM GSM Tx DCS Tx UMTS Tx
Problems with cross-talk
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Exposure of general public, November 07 Measurement with "extra" exposure
GSM/UMTS base Microwave oven, Mobile phone, station, 350 m 30 cm 70 cm
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Exposure of general public, November 07 "Normal" situation
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Exposure of general public, November 07 Dosimeters: Questions to be discussed
• Limited sensitivity • Cross talk between different frequency bands • Measurement accuracy - Isotropicity - Influence of the user - Response to modulated signals - Summation of multiple signals in the same band • Functional and ergonomic aspects
Z Dosimeters seem to be very helpful for epi-studies, (although their quality need to be investigated in detail)
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Exposure of general public, November 07 Summary and conclusion
• Relevant exposures are: - mobile phone base stations (GSM+UMTS) and mobile phones - digital and analogue radio and TV broadcast - Wireless LAN and DECT cordless phones • Most services exhibit strong time variations (power control) and space variations (fast fading) → worst case exposure differs from averaged exposure • General comparison of exposures show: - Strongest exposure by sources near to body/body contact - Long/Medium/Shortwave radio service often underestimated • Dosimeters seem to be very helpful for epi-studies, (although their quality need to be investigated in detail)
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Exposure of general public, November 07