How Do I Measure EMFs?
A Gauss is a common unit of measurement of magnetic field strength. A Gauss meter is an instrument which measures the strength of magnetic fields. Inside a Gauss meter there is a coil of thin wire, typically with hundreds of turns. As a magnetic field radiates through the coil, it induces a current, which is amplified by the circuitry inside the Gauss meter.
Gauss meters may vary in the strength of the magnetic field they are capable of measuring. A meter used for measuring EMFs from power lines, transformers, substations and appliances around the home, for example, should be able to measure as low as .1 mg.
Gauss meters vary widely in price and accuracy. Meters have either a single axis coil or a triple axis coil. Single axis meters are much simpler than triple axis meters to manufacture and thus, are less expensive. To use a single axis meter you must point the meter’s one sensor in three directions — -the x, y and z axis. Then, you combine the three readings in a mathematical equation to calculate the combined field strength. Obviously, its far easier and more accurate to use a 3-axis meter. Triple axis Gauss meters are quite accurate, but they are also more expensive.
Another thing to watch out for when purchasing or renting a Gauss meter is whether or not it is frequency weighted. Most meters will read the same EMF strength no mater what the frequency.
As the human body appears to be sensitive to both the field strength AND the frequency, Gauss meters used for biological purposes should be “frequency weighted”. This means that if the field is different than 60 Hz the meter will consider the frequency and use it in calculating and displaying the EMF’s strength. This feature is why frequency weighted meters will show a higher EMF reading than those meters typically used by electricians and engineers.
An enormous amount of electricity is created at power generating stations and sent across the country through wires that carry high voltages. All power lines radiate electromagnetic fields. The question is: how much are the power lines near YOUR home radiating? The amount of EMFs coming from a power line depends on its particular configuration. Power companies know which power line configurations are best for reducing EMFs but most don’t feel the evidence supports costly changes in the way they deliver electricity.
A substation is an assemblage of circuit breakers, disconnecting switches and transformers designed to substations have been blamed for causing cancer clusters among nearby residents. Paul Brodeur wrote about several such cancer clusters in the July 9, 1990 issue of the New Yorker Magazine.
A key component of a utility’s electrical distribution network depends upon numerous, small transformers mounted on power poles. A transformer looks like a small metal trash can, usually cylindrical.
Even when the electrical service is underground, you will often see a metal box (usually square} located on the ground near the street. Many people don’t realize that when they see a transformer, the power line feeding the transformer is 4000 to 13,800 volts. The transformer then reduces the voltage to the 120/240 volts needed by nearby homes. Since these transformers can be seen in almost every neighborhood, they are a source of concern. EMFs near a transformer can be quite high, but due to its small structure, the field strength diminishes rapidly with distance, as it does from any point source. For this reason, having a transformer located near your home is usually not a major source of concern, although just to make sure, everyone should measure the field strength around it.
If your home has high EMF readings, it is important to determine the sources of the EMF so that remedial action can be taken, if possible. Many times a particular room will have a higher EMF reading. Check to see if the electricity is coming into the house on the wall outside that room. When this is the case, it is usually a good idea to block off that room and only use it for storage purposes.
Sometimes, the source of a high magnetic field is incorrect wiring. If you suspect that your home is wired improperly, obtain the services of a licensed electrician. Warning: Do not touch electric wires, even if you think the current is turned off. If you need to disconnect electrical circuits to determine the source of magnetic fields, you should call a licensed electrician.
Computers are a complicated subject. Know this: EMFs radiate from all sides of the computer. Thus, you must not only be concerned with sitting in front of the monitor but also if you are sitting near a computer or if a computer is operating in a nearby room.
The Swedish safety standard, effective 711/90, specifies a maximum of 0.25 mG at 50 cm from the display. Many US manufactured computers have EMFs of 5 – 100 mG at this distance. And know this too: the screens placed over monitors do NOT block EMFs. Not even a lead screen will block ELF and VLF magnetic fields. Space does not permit a more thorough discussion of computers. If you use a computer, it is important that you measure your EMF exposure with a Gauss meter and review the literature concerning the health impacts of computer use.
Electric Blankets and Waterbeds
Electric blankets create a magnetic field that penetrates about 6-7 inches into the body. Thus it is not surprising that an epidemiological study has linked electric blankets with miscarriages and childhood leukemia. This pioneering work was performed by Dr. Nancy Wertheimer and Ed Leeper, who originally discovered that magnetic fields were linked to childhood leukemia. Similar health effects have been noted with users of many electric blankets and waterbed heaters will emit EMFs even when turned off.
The devices must be unplugged to delete the EMF exposure Additionally, there is the issue regarding the vibrations that are generated by sleeping on standing water. There is less hard data in this area but some experts are concerned about the consequences.
Electric clocks have a very high magnetic field, as much as 5 to 10 mG up to three feet away. If you are using a bedside clock, you are probably sleeping in an EMF equivalent to that of a powerline Studies have linked high rates of brain tumors with chronic exposure to magnetic fields, so it is wise to place all clocks and other electrical devices (such as telephones and answering devices) at least 6 feet from your bed.
Fluorescent lights produce much more EMFs than incandescent bulbs. A typical fluorescent lamp of a office
ceiling have readings of 160 to 200 mg 1 inch away.
Microwave Ovens and Radar
Microwave ovens and radar from military installations and airports emit two types of radiation — microwave and ELF. Microwaves are measured in milliwatt per centimeter squared (mW/cm2) As of 1/1/93, the U.S. safety limit for microwave exposure is 1 mW/cm2, down from a previous 10 mW/cm2. The Russian safety limit is .01 mW/cm2. All microwave ovens leak and exceed the Russian safety limit. In addition, recent Russian studies have shown that normal microwave cooking coverts food protein molecules into carcinogenic substances.
When measuring microwaves from military and airport radar sources, 100% accurate readings can only be found with extremely expensive digital peak-hold meters. Why? Because analog devices begin to drop their reading immediately after the radar sweep passes. Thus, while an analog meter can show whether or not you are being exposed to radar EMFs, analog meters can’t show your true exposure. Although thousands of dollars to purchase, digital-hold meters capable of accurately detecting radar EMFs can be rented for several hundred to over a thousand dollars per month.
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