|Electromagnetic radiation is a self-propagating wave in space with magnetic and electric components. It travels at 300,000 kilometres per second or 186,000 miles per second; the speed of light. Electromagnetic radiation varies in characteristics depending upon its frequency of vibration and wavelength. Frequency is the number of waves per second measured in wave cycles per second or Hertz. Wavelength is the measure between two successive points of the wave measured in metres. Low frequency electromagnetic radiation has long wavelengths and high frequency electromagnetic radiation has short wave lengths.
The electromagnetic spectrum is an illustrative tool used to arrange electromagnetic radiation according to frequency and wavelength. The frequencies of vibration on the spectrum range from just above zero to 1 x10²² Hertz (Hz) and higher. Electromagnetic radiation at one end of the spectrum has low frequencies, long wavelengths and low energy and at the other end has extremely high frequencies, short wavelengths and very high energy.
Physicists classify electromagnetic radiation into types according to the frequency of the wave. As an example, the band of frequencies between 5 x 10³ and 3 x 10⁹ are classified as radio frequencies and the waves are known as radio waves. Similarly, the frequencies between 3 x 10⁹ and 3 x 10¹² on the electromagnetic spectrum are microwave frequencies and the waves are referred to as microwaves.
Scientists classify electromagnetic radiation to suit their needs by the effects it has on the human body. Thermal effects relate to the ability of the radiation to heat body tissue. Another classification separates electromagnetic radiation according to its ability to ionize body tissue. Ionizing radiation contains sufficient energy to dislodge electrons from atoms or molecules, break chemical bonds and thereby produce chemical changes within the body. Ionizations in sufficient quantity can be destructive to living tissue and cause DNA damage and mutations.
Another term used in discussions about electromagnetic radiation is electromagnetic field. An electromagnetic field is a physical field composed of two elements, magnetic fields and electric fields. The term generally is used to refer to both magnetic fields and electric fields because they normally occur together whenever electricity is in use. Magnetic and electric fields occur as invisible lines of force that carry energy. The energy radiates out from any wire or electric device energized with electricity. Physicists refer to magnetic fields as magnetic flux density and electric fields as electric flux density. Despite the fact magnetic fields and electric fields occur together, they each have there own distinct characteristics.
As electricity flows through wires and electrical devices, magnetic fields are created. The higher the current flow, measured in amperes (amps), the stronger the magnetic field. Magnetic field strength (magnetic flux density) is measured in units of Gauss, more commonly milligauss (mG) in North America and in Tesla (T) in Europe. The intensity of magnetic fields varies directly with current flow and decreases with distance from the source of the field. Because of the nature of magnetic fields they are difficult to shield against because of their ability to pass through most building materials. It is generally accepted that the safe limit for long term exposure to magnetic fields is 2 mG or preferably less.
The human body has a magnetic permeability similar to air and so will receive the full effect of any magnetic field it is exposed to. Most people will not sense they are being exposed to dangerous magnetic fields. This is one reason that long term exposure to significant magnetic fields can be so damaging to the body. During the Cold War the Soviets irradiated the United States Embassy in Moscow. Two successive ambassadors developed leukemia and numerous staff members developed cancer or the precursors to cancer.
In some cases individuals will suffer symptoms of over exposure such as headaches, nausea, dizziness and flu-like symptoms that could be warning signs from the body. In other cases, sufferers of chronic illnesses will notice exaggerations of their symptoms which will subside when their exposure is reduced. In far too many cases, individuals are unaware of over exposure until they are diagnosed with an illness or disease like immune system abnormalities or cancer.
There are a large number of sources of magnetic fields that one must be aware of inside and outside the home. Some examples are:
Wireless communication devices such as cell phones, pagers, cordless telephones, Blackberry and Bluetooth devices and wireless baby monitors.
Computer and electronic entertainment equipment; wired or wireless.
Wireless installations in the home or in public places such as security systems and wireless Internet connections.
Electrical equipment, heating equipment, fluorescent light fixtures, compact fluorescent lamps, halogen lighting fixtures and most major appliances.
Most small appliances.
Building wiring errors such as wiring faults, grounding faults, breaker panel errors, ground currents and code violations.
Spatial areas near cell phone/FM/TV antennae as well as electrical transmission and distribution wires and equipment.
Public buildings like hospitals, office buildings, shopping malls and casinos.
Workplace hazards such as office and communication equipment and hazards specific to the industry.
Electric fields form around any electrical wire that is charged with electricity but not flowing. This includes building wiring and electric wires attached to appliances plugged into electrical outlets and in the off mode. Electric field strength, measured in units of volts per metre (V/m) is related to the voltage of the electricity in the wire, the higher the voltage the stronger the field.
Electric fields are easily shielded. Shielded electrical wire is available to replace original building wire and shielded supply wires are available for retrofitting many types of appliances.
In an electric field the human body becomes a conductor. The ability of the body to act as a conductor will depend on its size and shape, whether or not it is grounded and its location within the field. The field will cause small electric currents to be produced on the surface of the skin and a small amount of electric radiation to enter the body. An electric field of sufficient strength may cause a current on the surface of the skin that will produce a tingling sensation.
It is a good idea to reduce or eliminate electric field levels in the living space. This of particular importance in rooms where significant time is spent such as in bedrooms, and on couches or chairs while watching television or reading. This can be accomplished by unplugging small appliances when not in use and removing extension cords from under beds, couches and chairs.
Special attention to eliminating electric fields must be paid in bedrooms. Electric fields from electric wiring close to the bed emit 60 Hz alternating current (AC) electric fields which disrupt the subtle DC currents and fields of the body. This energy has an agitating and disruptive influence that interferes with the body's ability to achieve deep and restful sleep. As a result, vitality levels are reduced and the function of the immune system is suppressed. The ability of the body to heal, rejuvenate and deal with chronic illness is compromised. A gland that is affected by electric currents is the pineal gland. It is this very important because it produces melatonin, a significant natural hormone. A lack of melatonin can result in depression, mood changes and psychiatric disorders. Compromised levels of melatonin reduces the body's ability to inhibit tumor growth and fight cancer particularly breast cancer and prostate cancer. In order to promote healthy levels of melatonin, it is important to maintain the bedroom in total darkness during sleeping hours.