EMR Exposure Limits & Assessment Methods for Mobile Phone Communications. Lindsay Martin Manager, Non-Ionising Radiation Section

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1 EMR Exposure Limits & Assessment Methods for Mobile Phone Communications Lindsay Martin Manager, Non-Ionising Radiation Section

2 Introduction How can we use Wireless Communication Safely? Wireless communication uses Radiofrequency (RF) Electromagnetic Radiation (EMR). EMR carries energy and has potential to harm human beings. Radiofrequency EMR is just part of a wide spectrum of EMR which includes different types of radiation with very different properties. Using RF EMR safely means we must understand where it is used, how humans are exposed to it, and how it affects humans. 2

EMR carries energy and has potential to harm human beings.

3 Protection Strategy Scientific Investigation Identify harmful effects and mechanism of action. Determine threshold (if any) for harm. Look for harmful effects of exposures below threshold. Develop Safety Standards Expert review of science Assess Exposures & Check compliance Educate, Inform & Regulate 3

Look for harmful effects of exposures below threshold.

4 What is Radiofrequency EMR? Known by various names:- EMR Electromagnetic Radiation EME Electromagnetic Energy EMF Electromagnetic Fields Electric Fields (E-fields, volts/metre, V/m) Magnetic Fields (H-fields, amps/metre, A/m) Characterised mainly by: FREQUENCY cycles per second or hertz, Hz POWER FLUX DENSITY watts/square metre, W/m 2 MODULATION/PULSE STRUCTURE EMR is a wave of electric and magnetic fields travelling at the speed of light. 4

Electric Fields (E-fields, volts/metre, V/m) Magnetic Fields (H-fields, amps/metre, A/m) Characterised mainly

5 Other forms of EMR Radiofrequency (RF) EMR ranges in frequency from ~10,000 Hz (10kHz) to ~100,000,000,000 Hz (100 GHz). Most uses are from 500 khz 5 GHz AM FM TV UHF Mobile/WiFi At higher frequencies, EMR is:- Infra-red radiation Visible light Ultra-violet radiation (UVR) X-rays (ionising radiation) Gamma-rays (ionising radiation) 5

Most uses are from 500 khz 5 GHz AM FM TV UHF Mobile/WiFi At higher frequencies,

6 Scientific Investigation Experiments on human volunteers: Expose humans to low levels of EMR Increase exposure until discomfort Monitor for signs of harm or biological effect Experiments on animals (in vivo) Experiments on cells (in vitro) Harmful effects depend on frequency of the EMR. Clearly established effects show a threshold. 6

biological effect Experiments on animals (in vivo) Experiments on cells (in vitro)

7 Established Effects of RF EMR At low frequency, electric fields can stimulate nerves, muscles and brain. At higher frequencies energy is absorbed as heat and increases temperature or makes body respond to remove heat (thermoregulate). Body organs with poor heat removal (e.g. Lens of eye, reproductive organs) can be more susceptible. If EMR is in very short pulses, effects of electric field on cells can be more important than heating. Effects of heating make finding any other effects difficult they prevent use of high exposures to accelerate other potential effects that might be there. 7

Body organs with poor heat removal (e.g. Lens of eye, reproductive organs) can be more susceptible.

8 Effects seen but not Established.. Other effects seen in some experiments but not consistently or reliably, or at high exposure levels, or not necessarily harmful... Changes to DNA in isolated cells or in animals. Changes to cell growth and reproduction. Changes in brain wave patterns, sleep patterns. Changes in abilities to carry out mental tasks. Subjective symptoms.... 8

exposure levels, or not necessarily harmful... Changes to DNA in isolated cells or in animals.

9 Other Scientific Investigation Study of human populations incidentally exposed to EMR Epidemiology Compare different populations (ecological study) Compare exposure and disease within a group at a defined time (cross-sectional study) Follow groups with different exposures within the population (cohort study) Compare exposures of people with disease with those without (case-control study) Occupational studies and residential studies ~ 200 studies in last 10 years. No clear evidence of harmful effects but some indications worthy of more research. 9

exposures within the population (cohort study) Compare exposures of people with disease with those without (case-control study)

10 Expert Reviews of Science National Expert Reviews e.g. Swedish SSI, U.K. AGNIR International Agency for Research on Cancer (IARC) Part of World Health Organization Classification for Carcinogenicity RF EMR Meeting May 2011 World Health Organization Environmental Health Criteria Monographs No. 137 Most recent for RF EMR in Start again this year following IARC review. 10

fr/ Part of World Health Organization Classification for Carcinogenicity RF EMR Meeting May 2011 World

11 Expert Reviews of Science International Commission for Non- Ionizing Radiation Protection (ICNIRP) Reviews of Scientific Evidence Exposure to high frequency electromagnetic fields, biological effects and health consequences (100 khz-300 GHz) - Review of the Scientific Evidence and Health Consequences. Munich: International Commission on Non-Ionizing Radiation Protection; Epidemiologic Evidence on Mobile Phones and Tumor Risk: A Review. Epidemiology 20: ;

consequences (100 khz-300 GHz) - Review of the Scientific Evidence and Health Consequences.

12 Exposure Guidelines & Standards WHO Framework for developing health-based EMF standards Select: Scientific Database Perform: Risk Assessment Determine: Threshold Levels Select: Safety Factors Set: Exposure Limits Basic restrictions Reference levels Ensure Overall Practicability 12

Assessment Determine: Threshold Levels Select: Safety Factors Set:

13 Exposure Guidelines & Standards ICNIRP Guidelines for Limiting Exposure to Time-Varying Electric, Magnetic, and Electromagnetic Fields (up to 300 GHz). Health Physics 74 (4): ; Widely used as basis for national exposure limits. IEEE (International Committee on Electromagnetic Safety) IEEE C IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields,3 khz to 300 GHz. Both documents contain extensive discussion of scientific evidence and basis of exposure limits. 13

IEEE (International Committee on Electromagnetic Safety) IEEE C95.

14 Exposure Guidelines & Standards ARPANSA Radiation Protection Standard for Maximum Exposure Levels to Radiofrequency Fields - 3 khz to 300 GHz (2002) Based on ICNIRP (1998) guidelines Contains some practical implementation details Includes precautionary minimisation requirement for public exposure: Minimising, as appropriate, RF exposure which is unnecessary or incidental to achievement of service objectives or process requirements, provided this can be readily achieved at reasonable expense. and The incorporation of arbitrary additional safety factors beyond the exposure limits of this Standard is not supported. 14

as appropriate, RF exposure which is unnecessary or incidental to achievement of service objectives or process requirements, provided this can be readily

15 Occupational & Public Exposure All example guidelines include twotier exposure limits providing larger safety factors for public exposure. ICNIRP occupational & public. IEEE uncontrolled & controlled environments. Use of occupational limits is usually restricted to trained workers involved in RF installation, maintenance etc. Not just those exposed during employment, such as cleaners, painters, etc. Pregnant workers revert to general public limits. 15

Use of occupational limits is usually restricted to trained workers involved in RF installation, maintenance etc.

16 Exposure Limits Specific Absorption Rate (SAR) difficult to measure. Basic limitation on rate of absorbed energy from RF EMR to prevent tissue damage or unacceptable levels of heating. Whole Body Average SAR 0.08 W/kg (public). Localised SAR 2.0 W/kg for most exposed 10 g of tissue (public). e.g. Mobile phone handsets. Reference Levels for Electric and magnetic fields (or derived power flux density) more practical. Intended to assure SAR limitation is achieved. 16

Whole Body Average SAR 0.08 W/kg (public). Localised SAR 2.0 W/kg for most exposed 10 g of tissue (public). e.g. Mobile phone handsets.

17 Exposure Limits & Target Values SAR limits and Reference Levels for fields are Ceiling values not to be exceeded (taking 6 minute average or averaging over body into account). Public limits usually apply everywhere members of public could be expected to go. Some countries, regions or cities may have target values intended as a precautionary measure. These limits are not based on thresholds and are often the intended to address community concern. These sometimes refer only to levels of EM fields indoors, or averaged over 24 hours, only some technologies, etc. Not directly comparable with limits in standards. 17

Some countries, regions or cities may have target values intended as a precautionary measure.

18 Assessment of Exposures Assessment may be by MEASUREMENT or by CALCULATION (usually computer software). Different choice of method for different circumstances. MEASUREMENT: often chosen very close to antennas where fields may vary rapidly with location and be complicated by multiple sources, reflection, etc. CALCULATION often chosen for environmental assessments for public exposure relatively far away from antenna, where contribution of single transmitter is required. Can be made very conservative. Combination of MEASUREMENT and CALCULATION provides greater confidence in assessment. Method may depend on REGULATOR s requirements. 18

CALCULATION often chosen for environmental assessments for public exposure relatively far away from antenna, where contribution of single transmitter is

19 Assessment of Exposures Assessment requires appropriate instrumentation or software. Appropriate skill, training and understanding. Calibration of instruments and regular checks. Calculation can be quite simple for distant assessments based on conservation of energy and published data for antennas, transmitter etc. Example: ARPANSA EME Reports for new Mobile Phone Base Stations Near worst-case estimate of exposure levels at 1.5 m above ground level with transmitters all operating at full power. More sophisticated computer models used close to antennas where Electric and Magnetic fields must both be calculated. 19

Calculation can be quite simple for distant assessments based on conservation of energy and published data for antennas, transmitter etc.

20 Summary Radiation Protection for EMR Scientific knowledge of health effects. Science-based exposure limits. Ability to assess exposures. Engineering (barriers, masts) or administrative (warning signs, training) controls to keep people away from areas where exposures exceed limits. On-going work Monitoring of new research for new evidence and taking into account new technologies where required. Information for concerned public 20

Engineering (barriers, masts) or administrative (warning signs, training) controls to keep people away from

21 Thank You 21

Human Exposure Limits

Human Exposure Limits Session 3 0 Version December 2014 Learning objectives In this session we will: Learn about the international exposure limits for workers and the public Learn about methods for assessing