Table of Contents

Cover

Dedication

Title

Preface

Acknowledgments

1 Concepts of Electromagnetic Fields

1.1. Concepts of fields
1.2. Waves, frequencies and wavelengths
1.3. Propagation of electromagnetic waves
1.4. Type of radiation

2 Sources of Electromagnetic Fields

2.1. Natural fields
2.2. Artificial fields

3 Biophysical Mechanisms

3.1. Interactions with matter
3.2. Interaction with biological tissues
3.3. Coupling with the human body

4 Biological Effects of Electromagnetic Fields

4.1. Direct effects
4.2. Indirect effects

5 Exposure Limits for Electromagnetic Fields

5.1. General considerations
5.2. Low-frequency limits for direct effects
5.3. Limits for magnetic fields <1 Hz for direct effects
5.4. High frequency limits for direct effects
5.5. Limits for indirect effects
5.6. Summary of exposure limits
5.7. People at particular risk

6 Exposure Indices

6.1. General introduction
6.2. Signals and definitions
6.3. Introduction to exposure indices
6.4. Exposure index for high-frequency fields
6.5. Exposure Index for low-frequency fields
6.6. EIs: contact currents and induced currents
6.7. Summary of exposure indices

7 Applications of Exposure Indices

7.1. Introduction
7.2. Theoretical signals
7.3. Real signals
7.4. Conclusion on the index calculation examples

8 Exposure Assessment

8.1. Introduction
8.2. Measurement: general
8.3. Measuring low-frequency fields
8.4. Measuring high-frequency electromagnetic fields
8.5. Measuring the contact current and induced current
8.6. Introduction to dosimetry

9 Implementation of Directive 2013/35/EU

9.1. Context of the directive
9.2. Implementation of the directive

Appendix 1: Equipment and Workplaces Classification

A1.1. Non-exhaustive list of equipment and workplaces where it is unlikely that electromagnetic fields would be a risk for most workers
A1.2. Non-exhaustive list of equipment where electromagnetic fields may pose a risk to ALL workers
A1.3. Non-exhaustive list of equipment in addition to those in table A1.2 where electromagnetic fields may pose a risk to workers at particular risk, i.e. pregnant workers or workers with passive implanted medical devices (excluding workers with active implanted medical devices)
A1.4. Non-exhaustive list of equipment in addition to those in tables A1.2 and A1.3 where electromagnetic fields may pose a risk to workers at particular risk, i.e. workers with active implanted and active body worn medical devices

Appendix 2: Weighting Filters

A2.1. Weighting filter: introduction
A2.2. Weighting according to the EMF Directive (ICNIRP 2010)

Glossary

Bibliography

Index

End User License Agreement

List of Tables

1 Concepts of Electromagnetic Fields

Table 1.1. Summary of electric fields
Table 1.2. Summary of magnetic fields
Table 1.3. Summary of electromagnetic fields and their propagation
Table 1.4. Classification of frequencies
Table 1.5. ISM frequency bands
Table 1.6. Characteristics of electromagnetic radiation

2 Sources of Electromagnetic Fields

Table 2.1. Measured electric field [EDF 05, WHO 07]
Table 2.2. Measured magnetic field [EDF 05, WHO 07]
Table 2.3. Radio and television services
Table 2.4. Mobile telephone services and frequencies in Europe
Table 2.5. Relative radiation times measured for various Wi-Fi applications (IEEE 802.11g protocol – OFDM 54 Mbps)

3 Biophysical Mechanisms

Table 3.1. Conductivity of various media
Table 3.2. Relative permittivity of various media
Table 3.3. Electrical properties of common materials
Table 3.4. Electrical properties of biological tissues
Table 3.5. Penetration and absorption of electromagnetic waves by tissues
Table 3.6. Human body exposed to low-frequency electric fields
Table 3.7. Human body exposed to low-frequency magnetic fields
Table 3.8. Summary of the coupling mechanisms of electric, magnetic and electromagnetic fields

4 Biological Effects of Electromagnetic Fields

Table 4.1. Summary of effects caused by magnetic fields
Table 4.2. Biological effects depending on absorption level (SAR) for an exposed adult in a relaxed state
Table 4.3. Summary of short-term effects caused by electromagnetic fields
Table 4.4. Summary of long-term effects caused by electromagnetic fields

5 Exposure Limits for Electromagnetic Fields

Table 5.1. Basic restrictions or exposure limit values for workers according to Directive 2013/35/EU
Table 5.2. Basic restrictions for the general population (public) according to the 2010 ICNIRP Guidelines
Table 5.3. Basic restrictions for the general public according to the 1998 ICNIRP Guidelines
Table 5.4. Action levels for exposure of workers to magnetic fields between 1 Hz and 10 MHz according to the 2013/35/EU Directive
Table 5.5. Reference levels for exposure of the general population to magnetic fields between 1 Hz and 10 MHz according to the 2010 ICNIRP Guidelines
Table 5.6. Reference levels for exposure of the general population to magnetic fields between 0 Hz and 10 MHz according to the 1998 ICNIRP Guidelines
Table 5.7. Action levels for exposure of workers to electric fields between 1 Hz and 10 MHz according to the 2013/35/EU Directive
Table 5.8. Reference levels for exposure of the general public to electric fields between 1 Hz and 10 MHz according to the 2010 ICNIRP Guidelines
Table 5.9. Reference levels for exposure of the general public to electric fields between 1 Hz and 10 MHz according to the 1998 ICNIRP Guidelines
Table 5.10. Summary of low-frequency exposure limits
Table 5.11. Exposure limit values for external magnetic induction between 0 and 1 Hz
Table 5.12. Basic restrictions for a static or quasi-static field (frequency lower than 1 Hz) [ICN 14]
Table 5.13. Reference levels for external magnetic induction between 0 and 1 Hz [ICN 14]
Table 5.14. Exposure limit values (SAR) for exposure to a field between 100 kHz and 10 GHz
Table 5.15. Limit (S) for exposure to an electromagnetic field of over 6 GHz
Table 5.16. Exposure limit values (SA) for exposure to a field between 300 kHz and 6 GHz (1 joule = 1 W over 1 s)
Table 5.17. Exposure of workers to high frequencies (action levels)
Table 5.18. Reference levels (general public) at high frequencies
Table 5.19. Limits for currents induced (Ii) in the limbs (ICNIRP 1998)
Table 5.20. Summary of high-frequency exposure limits
Table 5.21. Reference levels for currents due to contact with conductive objects located in an electromagnetic field
Table 5.22. Action values for static magnetic induction
Table 5.23. Summary of biological effects and exposure limits depending on frequency
Table 5.24. Example of people at particular risk wearing a medical device
Table 5.25. Types of damage for a few active medical devices exposed to electromagnetic fields
Table 5.26. Situations where failure of electronic implants is possible

6 Exposure Indices

Table 6.1. Examples of simple and complex waveforms
Table 6.2. Reminder of exposure indices

7 Applications of Exposure Indices

Table 7.1. Exposure indices of B₁(t) compared to the reference level (general public)
Table 7.2. Exposure indices for B₁(t) compared to action levels (EMF Directive)
Table 7.3. Exposure indices for B₂(t) compared to the reference level (general public)
Table 7.4. Exposure indices for B₂(t) in relation to action levels (EMF Directive)
Table 7.5. Exposure indices for B₃(t) compared to the reference level (general public)
Table 7.6. Exposure indices for B₃(t) in relation to action levels (EMF Directive)
Table 7.7. Exposure indices for B4(t) in relation to the reference level (general public)
Table 7.8. Exposure indices for B₄(t) in relation to action levels
Table 7.9. Exposure indices for B₅(t) in relation to the reference level (general public)
Table 7.10. Exposure indices for B₅(t) in relation to the action levels (EMF Directive)
Table 7.11. Indices in relation to the limit for the general public (ICNIRP 98)
Table 7.12. Iindices (EMF Directive)

8 Exposure Assessment

Table 8.1. Total permissible uncertainties in exposure to electromagnetic fields

List of Illustrations

Preface

Figure 1. Structure of the book

1 Concepts of Electromagnetic Fields

Figure 1.1. Uniform electric field between two parallel planar electrodes
Figure 1.2. Non-uniform electric field between two electric conductors of opposite polarity
Figure 1.3. Surface accumulation of charges on a conductor in an electric field
Figure 1.4. Magnetic field line around a wire
Figure 1.5. Illustration of Faraday’s law: surface subjected to a variable magnetic flux
Figure 1.6. Decrease in the magnetic field for various types of source
Figure 1.7. Two electrodes under time-varying voltage create an electric and magnetic field
Figure 1.8. Dipole antenna with electric field and magnetic field
Figure 1.9. Time profile of a sinusoidal wave
Figure 1.10. Energy dispersal with distance
Figure 1.11. Exposure becomes uniform far away from the source
Figure 1.12. Spatial representation of an electromagnetic wave in the far field
Figure 1.13. Decrease of the electric field, the magnetic field and the power density with the distance from the source
Figure 1.14. Base station antenna radiation pattern
Figure 1.15. Representation of near- and far-field zones
Figure 1.16. Electromagnetic spectrum and applications

2 Sources of Electromagnetic Fields

Figure 2.1. Simplified representation of a conventional MRI scanner
Figure 2.2. Magnetic induction recorded on board a TGV
Figure 2.3. Maximum transverse electric field depending on the configuration of the cables (determined by the pylons) [APA 06]
Figure 2.4. Example of the daily current load of a 400 kV power line over the four seasons (source: RTE)
Figure 2.5. Cross-section view of the magnetic field, depending on the type of pylon [APA 06]
Figure 2.6. Magnetic induction heating
Figure 2.7. Arc welding station
Figure 2.8. Principle of resistance spot welding
Figure 2.9. Portable spot welding gun and stationary spot welding gun
Figure 2.10. The objects gradually leave the magnetic field, becoming demagnetized
Figure 2.11. Principle of magnetization through circulation of magnetic flux
Figure 2.12. Principle of a telecommunication link
Figure 2.13. Electric field around a GSM base station mounted on the roof of a block of flats (source: ANFR)
Figure 2.14. Electric fields in the axis of an antenna and on the ground
Figure 2.15. UHF RFID system
Figure 2.16. UHF electronic passive tag
Figure 2.17. NFC electronic tag (13.56 MHz)
Figure 2.18. Dielectric loss welding press
Figure 2.19. Kitchen microwave oven
Figure 2.20. Magnet therapy treatment [AND 13b]
Figure 2.21. Transcranial magnetic stimulation
Figure 2.22. Diathermy treatment
Figure 2.23. Electrosurgery: monopolar scalpel
Figure 2.24. Electrosurgery: bipolar scalpel.

3 Biophysical Mechanisms

Figure 3.1. Complete process of the mechanisms that may lead to effects on the health and well-being
Figure 3.2. Electric current in a conductor when an electric field is applied
Figure 3.3. Representation of the electronic polarization of an atom
Figure 3.4. Representation of ionic polarization
Figure 3.5. Water is composed of polar molecule (H₂O)
Figure 3.6. Representation of the orientation polarization of polar molecules
Figure 3.7. Representation of macroscopic polarization
Figure 3.8. Representation of the space charge polarization
Figure 3.9. Decrease in electric permittivity with frequency
Figure 3.10. Dielectric sample and equivalent electric circuit made up of a resistor and capacitor in parallel
Figure 3.11. a) Electrical conductivity of some biological tissues; b) electrical permittivity of some biological tissues
Figure 3.12. Representation of a wave propagating between two media with different dielectric properties
Figure 3.13. Penetration depth between 10 MHz and 100 GHz for various tissues (very high, high and low water content). The vertical dashed line corresponds to the microwave ovens and Wi-Fi frequency
Figure 3.14. Decrease in SAR as a function of the depth from the internal surface area of a homogeneous medium
Figure 3.15. Body exposed to a low-frequency electric field
Figure 3.16. Insulated body exposed to an electric field
Figure 3.17. Body exposed to a uniform vertical electric field of 10 kV/m at 60 Hz. The current density is more significant when the cross-section is reduced
Figure 3.18. Currents caused by a time-varying low-frequency magnetic field in a human body (the magnetic flux is perpendicular to the frontal plane)
Figure 3.19. Absorption of the electromagnetic field as a function of the frequency
Figure 3.20. Distribution of the SAR for a vertical polarized plane wave at various frequencies (Dr R. Findlay, private communication). For a color version of this figure, see www.iste.co.uk/staebler/electromagnetic.zip
Figure 3.21. Influence of the size of the body on the power absorbed during exposure to an electric field of 1 V·m^–1

4 Biological Effects of Electromagnetic Fields

Figure 4.1. Effects caused by electromagnetic fields
Figure 4.2. Temperature variation of two categories of biological tissue exposed to an electromagnetic field [AND 01]
Figure 4.3. Head exposure during a mobile telephone call. Highest levels occur in the outer layers of the head around the ear (source: IT'IS Foundation, ETH Zürich [ITI 10]). For a color version of this figure, see www.iste.co.uk/staebler/electromagnetic.zip
Figure 4.4. Current flowing through a body on contact with an insulated object exposed to an electric field
Figure 4.5. Ferromagnetic objects are banned

5 Exposure Limits for Electromagnetic Fields

Figure 5.1. Hierarchy of internal exposure limits
Figure 5.2. Exposure limit values (basic restrictions), expressed in internal peak electric field strengths, to protect workers from sensory effects (CNS) and health effects (PNS)
Figure 5.3. Basic restrictions expressed in internal rms electric field strengths for protecting the general public from sensory effects (CNS) and health effects (PNS)
Figure 5.4. General principles of exposure limits
Figure 5.5. Action levels for magnetic fields (rms values)
Figure 5.6. Reference levels in rms value for magnetic (induction) fields
Figure 5.7. Action values for electric fields applicable to workers (rms values)
Figure 5.8. Reference levels for electric fields applicable to the general public
Figure 5.9. Biological effects, induced fields, magnetic fields and limits
Figure 5.10. Limits for HF incident electric fields
Figure 5.11. Graphic representation of the limits for contact currents (ALs for workers; general public stands for general public)
Figure 5.12. Distribution of basic restrictions (exposure limit values)
Figure 5.13. Distribution of reference levels (action levels)
Figure 5.14. Active implant: pacemaker with bipolar lead
Figure 5.15. Hearing aids: cochlear implant
Figure 5.16. Passive implant: hip prosthesis

6 Exposure Indices

Figure 6.1. Example of peak value, rms value of a burst
Figure 6.2. Reference level (peak value) and module of the weighting function WL(f) depending on the frequency
Figure 6.3. Phase of the weighting function ( ϕ_i) as a function of the frequency
Figure 6.4. Application of the weighted peak method in the frequency domain
Figure 6.5. Piecewise linear and approximate weighting (public reference level ICNIRP 1998 from 8 Hz to 100 kHz – peak values)
Figure 6.6. Phase curve of the weighting filter
Figure 6.7. Application of the weighted peak method in the time domain
Figure 6.8. Principle of processing using the weighted peak method (EI^WPM) in the time domain
Figure 6.9. Representation of the processing of the EI^rms index
Figure 6.10. Magnetic induction and exposure index (time domain)
Figure 6.11. Magnetic induction and exposure index (frequency domain)

7 Applications of Exposure Indices

Figure 7.1. Signal composed of two sinusoids with similar amplitude and frequency (solid curve)
Figure 7.2. Waveform of a signal made up of two coherent sinusoids
Figure 7.3. Waveform B3(t) composed of two sinusoids
Figure 7.4. 50 Hz burst with a 80 ms duration repeating every 200 ms
Figure 7.5. Representation of B5(t) and W5(t) (chopped 50 Hz sinusoid)
Figure 7.6. Chopped sinusoid (ignition angle 45°) and signal weighted by the high action levels (HAL)
Figure 7.7. B₆(t): Square signal at 50 Hz with peak amplitude 100/√2 µT
Figure 7.8. Weighting applied to a square signal at 50 Hz
Figure 7.9. Response of the weighting filter W(t) normalized with the change in induction level (square waveform)
Figure 7.10. Response of the LAL weighting filter to a square signal at 50 Hz
Figure 7.11. Recorded magnetic induction and its rms value calculated over 20 ms when the tool is activated
Figure 7.12. Magnetic induction and rms value calcuated over 20 ms in a stabilized regime
Figure 7.13. Radiated B(t) and weighted W(t) magnetic induction/“general public”
Figure 7.14. Module of magnetic induction: peak and rms values
Figure 7.15. Exposure indices and measured by the fieldmeter on the tool and recorded
Figure 7.16. B(t) and weighted W(t) magnetic induction/LALs
Figure 7.17. Manual welding gun (source: AR0 Welding Technologies)
Figure 7.18. Welding current (zoom on the second period on the right)
Figure 7.19. Magnetic induction at the measuring point (zoom on one period on the right)
Figure 7.20. Weighted induction/LAL(zoom on one period on the right with B plotted as a dotted line)
Figure 7.21. Weighted induction/HAL (zoom on one period on the right with B as a dotted line)
Figure 7.22. Magnetic induction as a function of time and weighted inductions

8 Exposure Assessment

Figure 8.1. Functional synoptic view of a three-axis field meter
Figure 8.2. Diagram of a magnetic fields measurer equipped with a coil
Figure 8.3. Triaxial probe composed of three orthogonal coils for measuring magnetic fields (source: Narda STS GmbH)
Figure 8.4. Orientation of the coils of a probe for measuring magnetic fields (source: Narda STS GmbH)
Figure 8.5. Functional synoptic view of a magnetic fieldmeter
Figure 8.6. Relationship between the field at the center and the field measured (averaged) by a loop for three decreases in the magnetic field
Figure 8.7. Examples of monoaxial sensors for electric fields
Figure 8.8. Triaxial isotropic probe composed of three pairs of electrodesfor measuring an electric field
Figure 8.9. Sensor for measuring electric fields in relation to the ground
Figure 8.10. Example of a monoaxial sensor for electric fields and magnetic fields
Figure 8.11. Electric fieldmeter on its support (source: Narda STS GmbH)
Figure 8.12. Effects of proximity of the assessor during measurements of an electric field
Figure 8.13. Examples of antennae picking up the electric or magnetic field
Figure 8.14. Measurement using a broadband biconical antenna.
Figure 8.15. Example of narrowband triaxial measuring chain based on three monopolar antennae
Figure 8.16. Examples of measuring point positions for calculating an average spatial value
Figure 8.17. Measuring the contact current with a 20 Hz 10 MHz probe
Figure 8.18. Amperometric clamp (source: ETS.Lindgren Ltd.)
Figure 8.19. Measurement of the current induced during HF welding. For a color version of this figure, see www.iste.co.uk/staebler/electromagnetic.zip
Figure 8.20. Automatized measurement of the electric field in a phantom representative of a body part, to determine the mobile telephone SAR (source: Microwave Vision Group)
Figure 8.21. Ceramic triaxial probe for measuring an electric field of 30 MHz–3 GHz (source: Microwave Vision Group)
Figure 8.22. Breakdown of dosimetry calculations at low frequencies
Figure 8.23. Some members of the virtual family, distinguished by size and morphology. Some tissues are not shown, allowing the internal organs to be seen (source: IT’IS Foundation [ITI 10, ITI 14])
Figure 8.24. Example of modeled posture (source: IT’IS Foundation [ITI 10, ITI 14])

9 Implementation of Directive 2013/35/EU

Figure 9.1. Distribution of electrical equipment
Figure 9.2. General flow chart showing the implementation of Directive 2013/35/EU
Figure 9.3. Warning sign relating to electromagnetic fields
Figure 9.4. Restriction sign relating to electromagnetic fields

Appendix 2: Weighting Filters

Figure A2.1. Piecewise linear and approximate weighting (1998 ICNIRP – general public) from 8 Hz to 100 kHz (peak values)
Figure A2.2. Weighting filter principle
Figure A2.3. Phase curve of a first-order high-pass filter
Figure A2.4. Weighting function (Bode plot) according to low ALs for B as defined by the EMF Directive (peak values)
Figure A2.5. Phase of the weighting function according to low ALs for B
Figure A2.6. Weighting function according to high ALs for B as defined by the EMF Directive (peak values)
Figure A2.7. Phase of the weighting function according to high ALs for B
Figure A2.8. Weighting function according to limb AL(B)s (peak values)
Figure A2.9. Gain response of the weighting function for sensory effect ELVSs (peak values)
Figure A2.10. Phase response of the weighting function for sensory effect ELVS
Figure A2.11. Gain response of the weighting function for health effect ELVs
Figure A2.12. Phase response of the weighting function for health effect ELVS

Preface

“Knowledge is the only treasure that increases when shared”.

The laws of physics dictate that, whether we like it or not, we are all exposed to electric, magnetic and electromagnetic fields produced by the simple fact of using electricity. The number of electronic devices that radiate such fields has not stopped growing since the end of the 19th Century, when the first wireless communication took place and the spread of electricity began.

These devices have radically changed our lifestyle. They provide comfort, make tasks easier and offer opportunities for medical diagnosis and therapy. They have also deeply changed the way we communicate. Every proposed remote service must exist independently. In order to avoid interference between them, each one has its own frequency, so the radiation extends across the entire frequency spectrum.

This spectrum is a limited and fully regulated resource, the property of the states which grant its use. It will be increasingly busy around the clock. There will be no idle frequency, since future transmissions will dynamically manage the spectrum due to the arrival of software-defined radio providing ever more services. This means a higher data rate, and therefore more occupied frequencies.

Furthermore, the number of transmitters and receivers will continue to increase at a sustained rate. In addition to what are considered basic functions today (voice calls, internet and mobile video, contactless transactions, remote control), telephones will include Internet of Things (IoT) functions and others yet to be invented. The greater obstacles will be standardization and the protection of privacy, rather than technology.

We are eager for new technologies, despite the questions they raise for some people regarding the electromagnetic fields they radiate. These questions are logical because these fields are undetectable and intangible, so, for most of us, they remain a mystery.

Society’s concerns with radiation reappear with each technological advance, including the wireless telegraph in the 1930s, the television in the 1960s and the mass usage of wireless telecommunications since the beginning of the 1990s. The debate about power lines appeared belatedly at the end of the 1970s.

Nevertheless, these fields can be dangerous to health and safety if they are of high intensity. The harmful effects have been universally recognized for decades, but the possible effects on health after long-term exposure to low levels continue to be the subject of controversial debates.

Exposure to electromagnetic fields is a complex domain since, on the one hand, the relevant physical quantities are abstract, and, on the other, it is a multidisciplinary topic, given the interactions with biological systems. Physics, biology, medicine and metrology coexist.

In daily life, the general population is exposed to rather weak electromagnetic fields. The fields are stronger in occupational environments. Electrochemical processes, magnetic induction, welding, electricity distribution and telecommunications all expose workers to high field levels when they are close to the sources of radiation.

To protect workers and the public, limits were established. They have become a part of legislation.

There is a lot of confusion between electric, magnetic, and electromagnetic fields. This confusion extends to biophysical, biological and health effects. Moreover, certain publications use these terms incorrectly. There is also a lack of knowledge about sources of radiation. Few people know how exposure limits are determined, what precautions should be taken to carry out radiation measurements and, even less so, how these measurements and limits should be compared. Forming your own opinion in this domain requires at least some curiosity and an interest in science.

In addition, legislation requires that employers protect their employees from strong electromagnetic fields and that manufacturers produce compliant products that only radiate a limited amount or else provide use restrictions.

Intended audience

This book is intended for anyone who wishes to acquire a first level of knowledge about electromagnetic fields from 0 Hz to 300 GHz. Reading this book requires some scientific background. It contains several examples to facilitate understanding. The reader will be able to argue and discuss this controversial topic and analyze publications with a critical eye.

This book is also aimed at people who are responsible for the prevention of electromagnetic risk, such as engineers or technicians in charge of work conditions, health physicians, and, in particular, occupational doctors and trainers.

People in charge of ensuring compliance with regulations intended for the public and/or employees will have guidance on how to proceed and on metrology.

Manufacturers of household or professional materials will find elements to guide them in both the design (reduction and elimination of radiation at the source) and the production of an operating manual containing exposure data.

Finally, teachers can draw on several concrete applications to illustrate their lectures.

Disclaimer

This work is a summary of directives, recommendations, guides, standards and other official or scientific publications related to human exposure to electromagnetic fields. Most of these documents are references. In the event that the proposed reformulations are misunderstood, it is best to refer back to the original documents.

We have gone to great lengths to ensure that the content of this work is exhaustive and thorough. However, if our readers notice any errors, we would be grateful if they could communicate them so that subsequent editions can be corrected.

Organization and use of this book

This book summarizes all aspects of human exposure to electromagnetic fields from extremely low frequency (ELF) to radiofrequency or, to be more precise, from 0 Hz to 300 GHz. It allows the reader to form an opinion on the subject and adhere to regulations knowingly. This work is the result of several years of experience including presentations, standardizations, compliance assessments, measuring and designing equipment which radiates as low as reasonably achievable (www.exposition-cem.com).

images — **Figure 1**. *Structure of the book*

The content is structured as presented in Figure 1. There are nine chapters and two appendices, although some of these topics deserve a completely separate book. The main terms introduced can be found in the glossary.

Chapter 1: This chapter aims to introduce electromagnetism. This chapter, like those that follow, focuses on “human exposure”. Electric, magnetic and electromagnetic fields are explained by the laws of physics. They interact with organisms according to their nature and produce biological effects. It is essential to specify and clarify the vocabulary and definitions to avoid any misunderstanding. The relevant physical quantities are explained because they determine the effects and measurements. They also make it possible to define the exposure limit values. Although the frequencies extend infinitely, the “electromagnetic field” perimeter, as defined, is limited. This aspect has to be clarified. This chapter is fundamental because it is the gateway to grasping the human exposure concepts. For some, this chapter is a refresher for distant studies, but it should be approachable for those who have some gaps in their physical science backgrounds. Understanding this chapter is essential to take full advantage of this book.

Chapter 2: This chapter presents radiation sources encountered in daily life, others which are present in the workplace as well as others which are used for diagnostic or therapeutic purposes. It is impossible to be exhaustive because the sources are so numerous and heterogeneous.

Chapter 3: This chapter describes biophysical mechanisms. How do fields interact with material, in particular with biological tissue? This chapter explains why these tissues do not have the same electric properties as most materials used in electrical engineering. This chapter also takes a macroscopic approach. It describes how fields penetrate the human body and how they behave according to their nature and frequency.

Chapter 4: This chapter discusses the biological effects of fields, as well as the sensory and health effects. When the fields are intense, they can disturb certain senses or be imperceptibly harmful to health. This chapter presents the recognized acute effects as well as a summary of the studies on chronic (long term) effects. Direct effects are distinguished from indirect effects. The definitions are recalled to avoid confusion.

Chapter 5: Exposure limits (basic restrictions, reference level, etc.) logically follow biological effects. These limits were established to prevent adverse effects on health and well-being. This chapter also justifies the distinction between exposure of the general public and workers. It explains how these limits are determined. The values are summarized and illustrated in order to be quickly interpreted and compared. This chapter also considers people or workers at particular risk.

Chapter 6: This chapter explains the methods of comparison between measured or calculated fields and limit values, especially when these fields have complex waveforms. These methods are as significant as the limit values when assessing an exposure situation. In particular, the weighted peak method used to assess low-frequency exposure is introduced. Necessarily, this chapter includes many formulas. They may seem complex, but in reality most of them are comprehensible even to those readers who have some mathematical gaps.

Chapter 7: This chapter supports the previous one with examples of theoretical and real applications. Understanding them makes it possible to become familiar with the calculation methods presented. It can be read subsequently.

Chapter 8: This chapter introduces the basics of exposure assessment. Measuring techniques for electric, magnetic and electromagnetic fields are presented. Operating precautions and specific sources of uncertainty about the nature of these fields are explained. Measurement of contact and induced electric currents is also introduced.

The last section in this chapter succinctly approaches dosimetry, a technique used to precisely assess exposures when required or when measuring becomes impossible for physical reasons as indicated throughout this book.

Chapter 9: This chapter situates Directive 2013/35/EU (electromagnetic fields) in the European context and reformulates it by giving some practical guidance for its implementation. It refers to Appendix 1, which classifies equipment according to its radiation intensity. This chapter helps readers understand the interest of the exposure system limits presented in Chapter 5, which could seem obscure at the first reading.

Appendix 1 sorts equipment and workplaces according to the electromagnetic field strength to which the workers may be exposed. This appendix supports Chapter 9.

Appendix 2 presents the weighting functions implemented to assess exposure according to the calculation technique using the weighted peak method. This appendix complements Chapters 6 and 7.

Enjoy.

Patrick STAEBLER
March 2017

Human Exposure to Electromagnetic Fields

From Extremely Low Frequency (ELF) to Radiofrequency

Preface

Intended audience

Disclaimer

Organization and use of this book

Acknowledgments