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By Greg Lapin, N9GL
Chairman, ARRL RF Safety Committee
When you look at the news over the last few months, most of the RF Safety articles seem to be about the goings-on in Great Britain. What is happening in that country that is different from the rest of the world?
The British government has issued some revolutionary decisions about how cellular telephones and their base station should be treated. Are these decisions warranted?
The good news, at least for the ham radio community, is that most of the conclusions drawn by the government in Great Britain are directed toward the cellular telephone industry. The bad news is that RF is RF, and the same actions could be directed toward hams some time in the future.
It all started the same way it starts anywhere. The politicians in Great Britain want to know if their constituents are at risk from the proliferation of cellular telephones. They form a panel of scientists to answer the question. Their panel is called the Independent Expert Group on Mobile Phones and is chaired by Sir William Stewart, a professor of biology from Scotland who has served in many scientific advisory roles to the government. The press called this panel the Stewart Commission. The panel answers to the National Radiological Protection Board, a government agency tasked with providing this kind of information.
So far, this is analogous to the United States, only the names have been changed. Congress chartered the National Council for Radiation Protection several decades ago and they have formed subcommittees to study the effects of different technologies, including cellular telephones. One difference in the British case is that the IEGMP considered more than the scientifically substantiated biological interactions of radio frequency energy. It also dealt with sociological issues such as the aesthetics of cellular tower placement, technological issues such as radio frequency interference, and the fears of the general populace. In April 2000, it published its findings, which the press called the Stewart Report.
The Stewart Report is 160 pages long and is a reasonably accurate summary of the issues that they had studied. Some of their conclusions have been widely distributed by the press. In short, they say the following:
The balance of evidence to date suggests that exposures to RF radiation below NRPB and ICNIRP guidelines do not cause adverse health effects to the general population...we recommend that a precautionary approach to the use of mobile phone technologies be adopted until much more detailed and scientifically robust information on any health effects becomes available.
Perhaps the most widely quoted conclusion is with regard to exposure in children:
If there are currently unrecognised adverse health effects from the use of mobile phones, children may be more vulnerable because of their developing nervous system, the greater absorption of energy in the tissues of the head (paragraph 4.37), and a longer lifetime of exposure. In line with our precautionary approach, we believe that the widespread use of mobile phones by children for non-essential calls should be discouraged. We also recommend that the mobile phone industry should refrain from promoting the use of mobile phones by children.
The NRPB and ICNIRP guidelines that the Stewart Commission refers to are RF Safety standards that were developed in Europe. The FCC bases its RF Safety regulations on ANSI/IEEE and NCRP standards. However, all of the safety standards are based on the same scientific research and are very similar in their definitions of safe exposure limits.
The precautionary principle is not new. In the 1980s, the FDA proposed a principle of prudent avoidance. The basis of this principle is that one can use RF-emitting devices whenever necessary, but if it is possible to avoid them, one should. In the intervening years, considerable research and reasonable safety standards have been developed, and this phrase rarely is heard today. The Stewart Report is advocating it once again.
As I have mentioned in previous months, for anything that changes, or mutates, DNA--a condition that can lead to the formation of cancerous cells--children are more at risk than adults are. This is because children are growing, and their cells are naturally dividing. Something that leads to DNA mutation is more likely to cause cancer when there are many cells that are dividing at one time. Thus, it can be argued that children are more at risk in the presence of DNA mutating energy than adults are.
This is the basis of the British decision that children should be prevented from using cellular telephones. However, since the Stewart Commission did not identify radio frequency energy as one that mutates DNA, the British have decided to apply the precautionary principle "just in case."
It is unfortunate that the reasoning behind this decision is not understood by many of the decision-makers. The Stewart Commission used the correct reasoning to apply their precautionary principle to children in a greater degree than to adults. This is not the case with many of the other comments that are being bandied about in Great Britain. A recent set of theories put forth by a British physicist and that immediately made headlines spoke of the brain as if it were an electronic device prone to radio frequency interference. In addition, the same paper claimed that children are more prone to damage from radio frequency energy because they have weaker immune systems than adults.
This physicist should have concentrated on physics. Not only are his biological theories unfounded, but many of the same theories have been presented before and studied experimentally--all with no positive results.
It is unfortunate that otherwise good scientists do not go to the necessary work to learn what was done previously and to build on it. It's not easy. There are more than 1000 published studies of biological interactions with RF that have varying degrees of accuracy. It is an enormous task to read and evaluate the past work in the field, but this is necessary if progress is to be made. This task was undertaken by IEEE SCC-28 in preparation for the next revision of their RF Safety standard C95.1. The Stewart Commission also referred to about half of these studies--an ambitious undertaking considering the relatively short amount of time that they met to formulate their report.
What seems to be more important in the field of RF Safety these days is that many people want to get their names in front of the public. It's amazingly easy to do. Just come up with a theory--preferably one that will shock and scare the public. Make sure that the press hears about your theory, and, voilà, you are a household name. Many theories sound logical, but when confronted with the results of experimental studies they often fall apart. To present such a theory in a vacuum, without benefit of the results of past work done on the subject, is clearly irresponsible science.
Whether or not one wants to exercise prudent avoidance is a personal choice. For instance, I usually take a step back from the microwave oven when it is in operation. I know that microwave ovens are tested to meet strict FDA emission standards, and my exposure from it would not be harmful. However, taking a step back from the oven does not affect my life much, and it has become a habit. I don't let prudent avoidance affect my Amateur Radio operations, since I don't feel that avoidance of ham radio is prudent. If I could convince my children to become hams, I would not have them prudently avoid the radio either.
Whatever you decide, enjoy the holidays and try to get some quality time on the air.
Editor's note: Greg Lapin, N9GL, started working in the RF safety world after spending many years first studying cardiac function imaging and then brain tumor kinetics. He serves as chairman of the ARRL RF safety Committee and as a member of the IEEE Committee on Man and Radiation. A former professor of Biomedical Engineering and Neurology at Northwestern University, Lapin now works as a consulting professional engineer in the electronics industry. He was first licensed while a teenager in 1969 and continues to be fascinated by virtually all aspects of Amateur Radio. One of his many interests is electronic design, and he is the author of Chapter 8, "Analog Signal Theory and Components" in The ARRL Handbook for Radio Amateurs. His non-ham interests include making things grow in his garden and serving as commissioner of the local children's softball league. At other times--when he is not working or helping his kids with their homework--you might find him with the local emergency services agency, climbing his tower, building a new QRP rig, playing with his APRS setup, responding to QSL cards, going off on a DXpedition, or trying to get that "new one." You can reach him by email at g.lapin@ieee.org.
