Definitions and Sources

Electric fields are created by differences in voltage: the higher the voltage, the stronger will be the resultant field. Magnetic fields are created when electric current flows: the greater the current, the stronger the magnetic field. An electric field will exist even when there is no current flowing. If current does flow, the strength of the magnetic field will vary with power consumption but the electric field strength will be constant.

(Extract from Electromagnetic fields published by the WHO Regional Office for Europe in 1999 (Local authorities, health and environment briefing pamphlet series; 32).

Natural sources of electromagnetic fields

Electromagnetic fields are present everywhere in our environment but are invisible to the human eye. Electric fields are produced by the local build-up of electric charges in the atmosphere associated with thunderstorms. The earth's magnetic field causes a compass needle to orient in a North-South direction and is used by birds and fish for navigation.

Human-made sources of electromagnetic fields

Besides natural sources the electromagnetic spectrum also includes fields generated by human-made sources: X-rays are employed to diagnose a broken limb after a sport accident. The electricity that comes out of every power socket has associated low frequency electromagnetic fields. And various kinds of higher frequency radiowaves are used to transmit information – whether via TV antennas, radio stations or mobile phone base stations.

The basics of wavelength and frequency

What makes the various forms of electromagnetic fields so different?
One of the main characteristics which defines an electromagnetic field (EMF) is its frequency or its corresponding wavelength. Fields of different frequencies interact with the body in different ways. One can imagine electromagnetic waves as series of very regular waves that travel at an enormous speed, the speed of light. The frequency simply describes the number of oscillations or cycles per second, while the term wavelength describes the distance between one wave and the next. Hence wavelength and frequency are inseparably intertwined: the higher the frequency the shorter the wavelength.

A simple analogy should help to illustrate the concept: Tie a long rope to a door handle and keep hold of the free end. Moving it up and then down slowly will generate a single big wave; more rapid motion will generate a whole series of small waves. The length of the rope remains constant, therefore, the more waves you generate (higher frequency) the smaller will be the distance between them (shorter wavelength).

What is the difference between non-ionizing electromagnetic fields and ionising radiation?
Wavelength and frequency determine another important characteristic of electromagnetic fields: Electromagnetic waves are carried by particles called quanta. Quanta of higher frequency (shorter wavelength) waves carry more energy than lower frequency (longer wavelength) fields. Some electromagnetic waves carry so much energy per quantum that they have the ability to break bonds between molecules. In the electromagnetic spectrum, gamma rays given off by radioactive materials, cosmic rays and X-rays carry this property and are called 'ionizing radiation'. Fields whose quanta are insufficient to break molecular bonds are called 'non-ionizing radiation'. Man-made sources of electromagnetic fields that form a major part of industrialized life - electricity, microwaves and radiofrequency fields – are found at the relatively long wavelength and low frequency end of the electromagnetic spectrum and their quanta are unable to break chemical bonds.

Electromagnetic fields at low frequencies

Electric fields exist whenever a positive or negative electrical charge is present. They exert forces on other charges within the field. The strength of the electric field is measured in volts per metre (V/m). Any electrical wire that is charged will produce an associated electric field. This field exists even when there is no current flowing. The higher the voltage, the stronger the electric field at a given distance from the wire.

Electric fields are strongest close to a charge or charged conductor, and their strength rapidly diminishes with distance from it. Conductors such as metal shield them very effectively. Other materials, such as building materials and trees, provide some shielding capability. Therefore, the electric fields from power lines outside the house are reduced by walls, buildings, and trees. When power lines are buried in the ground, the electric fields at the surface are hardly detectable.

Magnetic fields arise from the motion of electric charges. The strength of the magnetic field is measured in amperes per meter (A/m); more commonly in electromagnetic field research, scientists specify a related quantity, the flux density (in microtesla, µT) instead. In contrast to electric fields, a magnetic field is only produced once a device is switched on and current flows. The higher the current, the greater the strength of the magnetic field.

Like electric fields, magnetic fields are strongest close to their origin and rapidly decrease at greater distances from the source. Magnetic fields are not blocked by common materials such as the walls of buildings.

Electric fields: 
plugging a wire into an outlet creates electric fields in the air surrounding the appliance. The higher the voltage the stronger the field produced. Since the voltage can exist even when no current is flowing, the appliance does not have to be turned on for an electric field to exist in the room surrounding it.

Magnetic fields 
Magnetic fields are created only when the electric current flows. Magnetic fields and electric fields then exist together in the room environment. The greater the current the stronger the magnetic field. High voltages are used for the transmission and distribution of electricity whereas relatively low voltages are used in the home. The voltages used by power transmission equipment vary little from day to day, currents through a transmission line vary with power consumption.

Electric fields around the wire to an appliance only cease to exist when the appliance is unplugged or switched off at the wall. They will still exist around the cable behind the wall.

How do static fields differ from time-varying fields?
A static field does not vary over time. A direct current (DC) is an electric current flowing in one direction only. In any battery-powered appliance the current flows from the battery to the appliance and then back to the battery. It will create a static magnetic field. The earth's magnetic field is also a static field. So is the magnetic field around a bar magnet which can be visualized by observing the pattern that is formed when iron filings are sprinkled around it.

In contrast, time-varying electromagnetic fields are produced by alternating currents (AC). Alternating currents reverse their direction at regular intervals. In most European countries electricity changes direction with a frequency of 50 cycles per second or 50 Hertz. Equally, the associated electromagnetic field changes its orientation 50 times every second. North American electricity has a frequency of 60 Hertz.

What are the main sources of low, intermediate and high frequency fields?
The time-varying electromagnetic fields produced by electrical appliances are an example of extremely low frequency (ELF) fields. ELF fields generally have frequencies up to 300 Hz. Other technologies produce intermediate frequency (IF) fields with frequencies from 300 Hz to 10 MHz and radiofrequency (RF) fields with frequencies of 10 MHz to 300 GHz. The effects of electromagnetic fields on the human body depend not only on their field level but on their frequency and energy. Our electricity power supply and all appliances using electricity are the main sources of ELF fields; computer screens, anti-theft devices and security systems are the main sources of IF fields; and radio, television, radar and cellular telephone antennas, and microwave ovens are the main sources of RF fields. These fields induce currents within the human body, which if sufficient can produce a range of effects such as heating and electrical shock, depending on their amplitude and frequency range. (However, to produce such effects, the fields outside the body would have to be very strong, far stronger than present in normal environments.)

Electromagnetic fields at high frequencies

Mobile telephones, television and radio transmitters and radar produce RF fields. These fields are used to transmit information over long distances and form the basis of telecommunications as well as radio and television broadcasting all over the world. Microwaves are RF fields at high frequencies in the GHz range. In microwaves ovens, we use them to quickly heat food.

At radio frequencies, electric and magnetic fields are closely interrelated and we typically measure their levels as power densities in watts per square metre (W/m²).

Key points:

1.     The electromagnetic spectrum encompasses both natural and human-made sources of electromagnetic fields.

2.     Frequency and wavelength characterise an electromagnetic field. In an electromagnetic wave, these two characteristics are directly related to each other: the higher the frequency the shorter the wavelength.

3.     Ionizing radiation such as X-ray and gamma-rays consists of photons which carry sufficient energy to break molecular bonds. Photons of electromagnetic waves at power and radio frequencies have much lower energy that do not have this ability.

4.     Electric fields exist whenever charge is present and are measured in volts per metre (V/m). Magnetic fields arise from current flow. Their flux densities are measured in microtesla (µT) or millitesla (mT).

5.     At radio and microwave frequencies, electric and magnetic fields are considered together as the two components of an electromagnetic wave. Power density, measured in watts per square metre (W/m²), describes the intensity of these fields.

6.     Low frequency and high frequency electromagnetic waves affect the human body in different ways.

7.     Electrical power supplies and appliances are the most common sources of low frequency electric and magnetic fields in our living environment. Everyday sources of radiofrequency electromagnetic fields are telecommunications, broadcasting antennas and microwave ovens

The power distribution systems

Since the power distribution uses High Voltage (HV), there is a pervasive presence of Alternating Electric fields anywhere near Aerial power lines. These lines are supplied with devices (regulators and/or capacitor banks) to raise or lower their voltage depending on load, causing Transients when they are swithced on or off. These transients are expressed over many miles of wire as a step-change in Electric and Magnetic field, with subsequent oscillations that may last a few seconds. The Alternating Electric field may be present for several hundred feet to either side of the wiring, but is partially or fully absorbed by conductive structures such as trees, or fully absorbed by the moist soil when the wiring is underground. This Electric Field phenomenon is most pronounced in the grounded WYE system, because in the Delta system there is no ground and the fields are limited to interaction between the wires.

While many studies have been conducted that implicate the presence of an Alternating Magnetic field presence with diseases (and it is beyond the scope of this document to enumerate them), there is a recent study that implicated a Leukemia peak with children as being synchronized with the appearance of electrical distribution systems. This primarily implicates Alternating Electric (or Voltage) fields. That is because when electrification was initiated in the various communities, the Electric field was always available at 100% value 24 hours a day, while the Magnetic field was only beginning to exist, as many of the electric gadgets we know of today, did not exist then. [3]

In a properly wired system all current passing through a wire returns via a nearby wire. Magnetic Fields cancel, and nearby exposure is reduced. When they do not, a Net Current is produced which causes a Magnetic field that extends for substantial distance (perhaps several hundred feet). In a three-phase system, an attempt is made to keep the three energized wires (phases) balanced, but any divergence will cause net currents, and a Primary Magnetic Field. Bear in mind that because the Primary operates at High Voltages (HV), the currents in use are much reduced. Thus for any HV power system the impact from alternating Electric fields is always present at 100%, and depending on load, then also from the alternating Magnetic fields. A lightly-loaded line will still be energized to 100% voltage, similar to residential wires within walls, ceilings, and floors.

The domestic home wiring:

1) Knob-and-Tube, the oldest, worst, and still approved, (the wires are separated by 6 - 16 inches)
2) Romex, where the wires are insulated in PVC and fabric (older type), or a dual PVC jacket (newer type), and 
3) BX/MC, where the wires are insulated in a PVC jacket, and then shielded by a metallic armor.

Knob-and-Tube wiring uses supply and return wiring that are separated by 6 to 16 inches, depending on travel direction relative to installed structural lumber.This separation causes the greatest residential availability of Magnetic and Electric fields.

In contrast, the inherent cancellation of magnetic fields when wires are brought close to each other occurs because the magnetic fields associated with the supply and return currents are identical and flowing in opposite directions. The two are balanced.

Romex has adjacent supply and return wiring allowing for significant reduction of Magnetic fields. Not so with Electric fields, because with voltages one wire is theoretically at 0 volts where the other wire is at 120 volts (equating to a single wire having a net of 60 volts). The voltage available on Romex is not fully canceled by the adjacent Ground and Neutral wires, and radiates Electric fields into the adjoining spaces, right through the insulating jacket and walls/floors/ceilings. This produces a residential Alternating Electric ambiance that is curiously reminiscent of the inside of an electrified birdcage. The greatest majority of North American homes are wired with Romex. If you are environmentally sensitive in any fashion, and have not considered the Electric Field environment as an immediate biological irritant, you are deceiving yourself. Many individuals the author meets, point out that their Gaussmeter reads zero, and yet they are reacting to "something". They never considered the Electric Fields.

BX/MC is constructed similarly to Romex with the exception that there is a Metallic Armor around the wires. The Metallic Armor is connected to Ground and eliminates all Voltage emissions from associated wiring, other than voltage on the ground as in Stray Voltage.

Adding to the complexity of the types of wire employed, there is the presence of appliance and lighting cordage. This wire is simply encased in a plastic jacket and introduces AC voltage further into the living space.

When one is exposed to Static Magnetic fields, as from the Earth (which is mostly static), a resonant vibration of all Ions is induced throughout the body and this is normal. When that same person is exposed to an Alternating Magnetic field, internal currents are produced in the various structures of the body, whose strength will vary with the conductivity of the specific organ. These currents produce direct and indirect Ionization and subsequent abnormal chemistry. Frequency-related effects also occur, which are beyond the scope of this document.

When one is exposed to Static Electric fields, as from the Earth (which is mostly static except for very low frequency oscillations (Schumann Resonances) associated with electric storm activity anywhere on the planet, which help us maintain normal cycles), a whole body electrical alignment stress is produced, and again, this is normal. This is generally quite low in intensity. When that same person is exposed to Alternating Electric fields, two things happen: 1) a surface (body) voltage develops that can easily be measured, and 2) an internal whole-body alignment of all charged or polarized molecules occurs, which changes with the applied voltage (incidentally, humans are about 75% water, a polarized molecule). The alignment effects can bring about abnormal chemistry.

In a contemporary properly wired setting there will be lots of voltage (electric fields), if not from wiring internal to walls/floor/ceilings, then from appliance and lamp fixture cordage, or both. The most significant impact is suffered in the bedroom, where the body is attempting to rest, recuperate, and possibly heal.

The typical bedroom setting entails a mattress with a metallic spring base, nightstands, various light fixtures, alarms, telephone, etc. In such a setting the sleeping area is rich with Electric fields.