About every 15 minutes, someone is killed and several others are injured in auto accidents in the United States, yet our government has spent trillions of dollars to build the roads that make this carnage possible. These accidents shorten the average American life span by about four months from direct fatalities and perhaps as much as year when the indirect effects of injury, suffering, and family losses are considered. Now, we realize that this lost year is minor in comparison with the enormous loss of life caused by taxation rates that now exceed $20,000 per family per year - think of the increased safety and quality of life that money would buy if it remained in the hands of those who earned it. Still, traffic deaths are a major technological hazard. We do not, however, hear a clamor to ban automobile transportation. Various enviro groups do work to make autos more efficient and lighter in weight - which promotes the driving of additional dangerous miles and increases the likelihood of fatalities when accidents occur. We often wonder what form transportation would have taken without the vast highway subsidies. In any case, there seems to be a belief among the American people that our motor transportation technology adds more to their lives than is subtracted by its dangers. This may in fact be true. Personal transportation has added substantially to individual freedom. Furthermore, that freedom has greatly enhanced the advance of technology of all sorts, which is largely responsible for the increase of 8 years in life expectancy in developed countries since 1950 (from 66 years to 74 years - see 
Technological advance (the increased life expectancy since 1950 in less developed countries has been 22 years) is critically dependent upon the availability of electric power. Without inexpensive electric power, world-wide life expectancies would be much lower. Therefore, it is to be expected that the antitechnology earth-huggers who wish to rid this planet of a substantial fraction of its people (not including, of course, themselves, since a few sensitive and superior beings must remain to smell the flowers) would attack electric technology by any means available to them. Among their preferred demons are the electric and magnetic fields that are associated with the transmission and use of electric power.
The electromagnetic spectrum is very broad. The low end includes oscillations of 60 Hz (hertz or cycles per second) for the ordinary power in your wall outlets or even a fraction of a hertz for the field you will generate when you turn around to adjust your reading light and thereby move the molecules in your body relative to the earth's magnetic field. The high end in the ranges around 10
20 Hz (the total range is of unknown magnitude) includes the electromagnetic radiation emitted from radioactive decay, which is so energetic that it can tear electrons away from atoms and break chemical bonds and is therefore called ionizing radiation. We are continually bathed in ionizing radiation resulting from radioactive materials in our bodies and environment and from cosmic radiation - so much so that ionizing radiation from nuclear power plants is a negli-gibly small addition.In between are the frequencies of the Figure 1 microwaves that may have cooked your breakfast by increasing the rotation rate of the polar molecules such as water in your food and thereby heating it. (Remember those little rotators with quantized rotational energy levels that we described in the September 1995
Access to Energy.) Included also are the radio and television electromagnetic waves that bring us word from the enviros about the evils of electromagnetic radiation. (In the 1860s, James Clerk Maxwell combined the laws of electricity and magnetism with the laws of the behavior of light and discovered that a part of electric and magnetic fields is attenuated linearly with distance rather than as the square of the distance. This makes radio and television communication possible.) Living things are full of polar particles and biologically important electric and magnetic processes, and they do interact with electromagnetic fields. Ionizing radiation directly changes molecular structures. 
In so doing, it causes the beneficial effects of hormesis (see, for example, Access to Energy 22-8, p 3, April 1995) and also, if the dose is too great, harmful effects. High frequency radio and microwave radiation can cause injuries by heating living tissue. Therefore, there are strict safety limits of exposure for consumer microwave devices and even amateur radio transmitters - limits that are far above ordinary exposure levels.
Very low frequency fields are produced by ordinary alternating current electrical devices. Their magnetic fields diminish as the first power of the distance from a linear source and as the second power of the distance from a point source, and, for practical purposes, do not radiate. These magnetic fields are difficult to shield, exert a significant force on molecules in living things, and have been shown to have numerous interesting biological properties. Although these effects are also caused by non-manmade phenomena such as the magnetic field of the earth, power transmission and use is a substantial contributor.
The magnetic field of the earth is about 500 milliGauss (mG) at the surface. This includes small oscillating fields, but is largely static. The earth is also a spherical capacitor continuously being charged by lightning (about 100 strokes per second worldwide) and discharging with a time constant of about 18 seconds. The resulting electric field at the
surface is about 100 volts per meter of height. (See F. S. Barnes, "Interaction of DC Electric Fields with Living Matter'' in CRC Handbook of Biological Effects of Electromagnetic Fields, pp 99-119 (1986).) A changing magnetic field exerts a force on electrically charged bodies within the field. A charged body moving through a static magnetic field also experiences a force. The charged substances in a human body are, therefore, coupled to static and oscillating magnetic fields.For example, if you turn completely around at a speed of one revolution in six seconds, the electrical forces in your body exerted by the 500 mG static earth field will be equivalent to those exerted by about a 1.0 mG AC power line magnetic field oscillating at 60 cycle per second. Walking generates an equivalent of about 0.2 mG. (See "Sources and Characteristics of Electric and Magnetic Fields in the Environment'' by D. W. Deno and D. O. Carpenter in
Biological Effects of Electric and Magnetic Fields, Volume 2, ed. Carpenter and Ayrape-tyan, Academic Press (1994)).Figures 1, 2 and 4 are from the Deno and Carpenter article. Figure 3 is from "Electric and Magnetic Fields and Cancer: The Use of Field Exposure Measurements in Epidemiological Studies'' by S. Koifman and G. Thériault in Volume 1 of
Biological Effects of Electric and Magnetic Fields (1994). Figure 1 shows the spatial distribution of measured magnetic fields in a real estate office in mG. Fields near the typewriter and copier are as high as 30 mG but fall off rapidly with distance, so both chairs are at much lower levels. The chair in front of the computer terminal is at 0.2 to 0.5 mG - comparable to the effect of the static earth field if the chair's occupant does not sit very still. (For more, read Electromagnetic Fields and VDT-itis by Petr Beckmann available for $3 from Golem Press, Box 1342, Boulder, CO 80306.) These authors also give typical approximate values for household devices as: electric blanket at 1 cm distance, 20-30 mG; clothes washer, 4 mG; dishwasher, 4 to 7 mG; vacuum cleaner, 16 mG; hair dryer at 2 inches distance, 100 mG; electric razor at skin surface, 14 mG; hand circular saw, 100 mG; and gasoline driven chain saw, 150 to 500 mG.Figure 2 illustrates the magnetic fields measured in and around an elementary school near Ottawa, Canada, that result from a major transmission line energized at 230,000 volts passing very near the school in the right of way shown at the top of the figure along with one of the high voltage line towers. With the line turned off, values outside the school at sites 1 through 10 and 1 meter above the ground were 0.3, 0.2, 0.2, 0.1, 0.2, 1.4, 0.5, 0.6, 0.2, and 0.2 mG, respectively. With the line on, the values at 1-10 were 32.5, 16.4, 5.4, 2.6, 6.1, 8.1, 16.5, 24.0, 13.0, and 5.8 mG. With the line turned off, values inside the school at sites A through M were 0.3, 0.5, 0.3, 0.7, 2.5, 0.2, 0.2, 0.3, 0.3, 0.3, 0.4, 0.3, and 0.2 mG. With the line on, the values at A-M were 0.6, 0.6, 1.0, 1.4, 5.1, 2.2, 0.8, 1.6, 3.4, 3.8, 2.4, 2.2, and 1.9 mG. The highest values
in classrooms were at sites I and J of 3.4 and 3.8 mG. By comparison with classrooms L and M, which are closer to the power line, we can see that about half of the magnetic field in rooms I and J comes from the padmount transformer supplying electricity to the school. Inside the school rooms, the magnetic field from the high voltage transmission line varies from an average of 0.4 mG for those rooms farthest from the line to an average of 1.9 mG for rooms closest to the line.
Aside from electronic equipment inside the office, home, or school, the greatest exposure to magnetic fields is usually from the local lines to the structure. As I write this, I may be receiving about 1 mG from my computer monitor, but I may be receiving as much as 5 mG from the power line that supplies this building and goes by outside my window. Figure 3 shows that this is complicated. The power line itself has two, mostly parallel wires whose fields tend to cancel one another, but ground loops from other sources can be important.
Figure 4 shows measurements on city streets in Alexandria, Vir-ginia. As the distance from the electric power substation on Union Street increases, magnetic fields decrease, since there is less current in the transmission lines. However, peaks of magnetic field scattered through the pattern show fields arising from other sources. These 5 to 10 mG peaks are comparable to power line fields in much of the grid.
So, as the flying instructor said in
Top Gun, "you can run, but you can't hide.'' In fact, running in the earth's magnetic field may just cause your highest magnetic field exposure for the day. Perhaps this is one of the hidden health benefits of exercise. Living or working right beside a high voltage power line right of way does increase your exposure, but, if you use an ordinary complement of electrical devices, the power line exposure (obviously, this does not include hanging from the towers right under the line) is not of overwhelming importance.What about the health benefits or risks? Well, your body does detect these fields. There is a great amount of biological research showing all sorts of effects of electric and magnetic fields on living things. Most of these experiments are not immediately relevant to humans, but, taken as whole, it is clear that the human body - which, through its biochemistry, utilizes many electromagnetic processes - is affected by forces of the magnitudes caused by motion in the earth's magnetic field and by fields from electrical appliances and power transmission.
After large amounts of research effort (see, for example, the books referenced above), still no reproducible and significant negative health effects have been demonstrated. This does not mean that none exist. The positive health effects of electric power in increasing the quality and length of human life are, however, obvious. The great cost in human lives from the huge amount of resources that would have to be expended to substantially reduce magnetic field exposure is certainly not justified in the absence of proven significant negative effects.
Turn on the power and enjoy its benefits. Being struck by lightning is probably a greater electrical danger - but, of course, lightning is "natural,'' so it is a politically correct and acceptable risk.
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Vol. 23, No. 2
Newsletter: Access to Energy Newsletter Archive Volume: Issues Issue/No.: Vol. 23, No. 2 Date: October 01, 1995 01:06 PM Title: Morality in Medical Science
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