Electromagnetic Fields and Radiation

Human Bioeffects and Safety

Riadh W.Y. Habash

• Publisher: CRC Press
• Year: 2018
• eBook ISBN: 9781351830270
• Topic: Technology & Engineering
• Subtopic: Biotechnology in Medicine
• Index: Technology & Engineering

This reference explores the sources, characteristics, bioeffects, and health hazards of extremely low-frequency (ELF) fields and radio frequency radiation (RFR), analyzing current research as well as the latest epidemiological studies to assess potential risks associated with exposure and to develop effective safety guidelines.

Compiles reports and investigations from four decades of study on the effect of nonionizing electromagnetic fields and radiation on human health

Summarizing modern engineering approaches to control exposure, Electromagnetic Fields and Radiation discusses:

EM interaction mechanisms in biological systems

Explorations into the impact of EM fields on free radicals, cells, tissues, organs, whole organisms, and the population

Regulatory standards in the United States, Canada, Europe, and Asia Pacific

Evaluation of incident fields from various EM sources

Measurement surveys for various sites including power lines, substations, mobile systems, cellular base stations, broadcast antennas, traffic radar devices, heating equipment, and other sources

Dosimetry techniques for the determination of internal EM fields

Conclusions reached by the Food and Drug Administration, World Health Organization, and other institutions

1

Introductory Topics

1.1 GENERAL

Just as coal enabled the industrial revolution, electricity is the unseen fuel of modern life. The dramatic increase in the use of electricity for domestic and industrial purposes proves that electrical energy plays an important part in our society. It is impossible to imagine what our lives would be like without access to this source of energy. Technologies associated with electricity have made our lives easier. Modem society is indeed unworkable without the existence of electrical appliances. Likewise, emerging telecommunication services have greatly enhanced the ability of individuals and groups to communicate with each other and have facilitated the speed of information to persons and machines in both urban and rural environments.

Electricity use is taken for granted. It does not, however, come without risks. People would ideally like this technology to be risk free, but that is impractical in today’s society. In particular, there is the potential for shock from contact with electrical conductors. Also, the use of electricity results in the production of electric and magnetic fields or electromagnetic (EM) fields. These fields are invisible forces of nature, generated by electricity, which are present whenever electricity exists.

Although EM fields have become an essential part of our life through their numerous applications, there are mounting concerns about the bioeffects that might exist due to exposure to such fields. Since the beginning of the twentieth century, we have been surrounded with a huge sea of man-made EM fields due to the rapid growth of power grids, radio and television (TV) stations, radars, cellular communications, and various appliances at homes and workplaces.

1.2 HISTORICAL PERSPECTIVE

Electromagnetic force, which exists between all charged particles, was not born in a day. It had to go through the long process of being defined. The existing outlook of the role of electromagnetic force in life is not that of the visionary force of earlier days.

The influence of electricity on biology was observed as early as the eighteenth century. While investigating, Luigi Galvani (1737-1798), the known physician and professor of anatomy in Bologna, Italy, announced his discovery that two metals brought into contact with a frog muscle could cause the muscle to incur.

The nineteenth century saw rapid developments in medical applications and physiological effects of electricity and magnetism. Such developments were motivated by the theoretical evolution in EM theory by Faraday, Ampere, Gauss, and Maxwell as well as by the development of alternating current (AC) applications by Jacques Arsenne d’Arsonval (1851-1940), a physician-physiologist with a strong professional interest in electrical engineering and one of the world’s early bioengineers, and Nikola Tesla (1856-1943), a Serbian-American inventor and researcher who discovered the rotating magnetic field, the basis of most AC machinery.

Speculations regarding possible bioeffects due to exposure to EM fields began in those times, but rigid investigations started after World War II. By the mid-1970s, much of the concern was directed toward possible health hazards of radio frequency radiation (RFR). In the following years, with the help of the media, public concern diverted from RFR to extremely low-frequency (ELF) fields. Also, attention shifted from the strong electric fields near high-voltage power lines to those relatively weak magnetic fields produced by distribution lines that bring electricity to our homes. During the last few years, concerns regarding RF exposure from cellular phones have grown considerably. These concerns are generated because of the wide use of such equipment worldwide. Moreover, the concerns are largely inflamed by the fact that the cellular phone is placed very close to the user’s head.

Observation of the influence of electricity and, accordingly, EM fields on biological systems will continue to be complex and split up over various areas of research such as physics, engineering, biology, medicine, health, environment, and risk assessment and management.

1.3 QUANTITIES AND UNITS

Throughout this book, a quantity of importance is the field, which is a region with a corresponding value of some physical quantity at each point of the region. Under certain circumstances, fields produce waves that radiate from the source.

1.3.1 Scalar and Vector Quantities

A quantity that has only magnitude and an algebraic sign is called a scalar quantity, such as mass, time, and work. While a quantity that has magnitude as well as direction is called vector quantity, such as force, velocity, and acceleration. In order to distinguish vectors from scalars, it is advised to use bold letters for vectors. For example, A represents a vector quantity while A represents the scalar quantity.

EM problems involve three space variables; therefore, the solution tends to be quite complex. More complexity may arise due to dealing with vector quantities in three dimensions. Vector analysis provides the mathematical means needed for manipulating vector quantities in an effective and suitable way. Using vector analysis saves time and gives wide understanding of the associated physical laws.

In electromagnetics we work with scalar and vector quantities. A field is considered a scalar or vector quantity. For example, electric potential is a scalar quantity, while electric field intensity is a vector quantity.

1.3.2 Units

A measurement of any physical quantity must be expressed as a number followed by a unit. A unit is a standard by which a dimension can be expressed numerically. The units for the fundamental dimensions are called the fundamental or base units. While carrying out EM calculations, there are several systems of base units that are available. However, they may be broken into two main groups. First, the International System of Units (SI) introduced by Griorgi in 1901, including the meter-kilogram-second-ampere (MKSA) subsystem representing the four fundamental dimensions length, mass, time, and electric current, respectively. Second is the centimeter-gram-second (CGS) system. The units for other dimensions are called secondary, or derived units and are based on the above fundamental units.

Currently, most the engineers use the practical MKSA system. What is known as the Gaussian system is an unrationalized CGS system, which is mixed in the sense that electric quantities are measured in electrostatic units, while magnetic quantities are measured in EM units. The CGS system is used mainly in the area of physics, where certain simplification in formulas results.

The SI is the standard system used in today’s scien...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication
• Table of Contents
• Preface
• 1 Introductory Topics
• Part I: Extremely Low-Frequency Fields
• Part II: Radio Frequency Radiation
• Acronyms and Abbreviations
• Index