When x-rays and radioactive decay were discovered in the 1890s, most investigators did not pause to consider the potential health hazards. A number of people were seriously and even fatally injured. We've learned, as a result, that it is wise to be cautious about new technology.
In little over ten years, the number of people using handheld mobile phones has soared from zero to
2.5 billion. It's appropriate to ask whether these devices, which produce microwave radiation and are routinely pressed against the ear, pose a threat to users' health.
So far, there is no reason to believe that mobile phones are a major health threat. Physics tells us that low-power radio waves are harmless. Epidemiological studies have failed to produce clear evidence of ill effects.
And yet fears persist. There is a small but highly vocal group of people who are convinced that the signals transmitted by mobile phones pose a serious health hazard--and that the truth is being suppressed by an industry-government conspiracy. Not surprisingly, they dismiss evidence to the contrary as tainted.
Ironically, people who doubt that mobile phones represent a serious health hazard also help keep the controversy alive. They tend to embrace healthy skepticism. They know that our understanding of the physics is imperfect and incomplete. They know that we will have more concrete data as time passes. Unlike the conspiracy theory promoters, they don't want to rush to judgment.
What do we really know about mobile phones and health hazards? We know that there are two types of radiation: ionizing and non-ionizing. Ionizing radiation includes neutrons, alpha particles, beta particles, ultraviolet light, x-rays, and gamma rays. These forms of radiation involve highly energetic particles that can cause damaging chemical changes in human tissue. Radio signals, however, are non-ionizing radiation. Since mobile phones operate at microwave frequencies there is the possibility of heating living tissue. However, at mobile phone transmit power levels (typically well under 1 watt) and frequencies there is very little heating and it is mainly confined to the skin.
The belief that cell towers represent a more serious health hazard is simply misguided. Cellular base stations typically transmit at 50 watts of power. Though that is roughly 100 times greater power than a mobile phone, the power that humans are exposed to declines rapidly with distance. Keep in mind that the 800-MHz cellular band was reallocated from UHF-TV. A full power UHF-TV station transmits at 50,000 watts. While cell towers are often located in or near residential areas, they transmit at 1/1000th the power of UHF-TV stations that have been around for much longer.
Population studies of the alleged ill effects of mobile phones have been inconclusive at best. For example, a study of people who maintain cell site equipment found no evidence that they are more likely to suffer health problems than the general population. There has been some laboratory research suggesting that small animals subjected to radio frequency radiation exhibit a higher incidence of certain types of tumors. However, human beings are not laboratory mice. While we should certainly heed such warnings and check for similar effects in humans, we should not jump to conclusions.
Some people seem to think that all health hazards are man-made. However, there are many natural threats to human health. Population studies can't always discriminate between man-made and natural causes. My point is that we are never completely risk-free; people often accept increased risks in exchange for certain benefits. (Admittedly, things become more complicated when increased risks are imposed on people who were not a party to the original bargain, as argued by opponents of "second-hand smoke.")
While it must be conceded that the wireless industry has a potential motive for suppressing evidence of health hazards, it should also be recognized that people who search for such evidence may be motivated to fake it. It's unfair to suggest that industry is naturally inclined to lie while researchers are beyond reproach.
It seems fair to say that if mobile phone signals present a health hazard, it certainly isn't immediate and it probably isn't very significant. Given that, let common sense prevail: If we run away from all potential risks we will never achieve any benefits.
Today I am inaugurating a new feature focusing on the old: reviews of classic books, articles, and documents in the history of technology.
I just finished reading Michael Pupin's engaging and inspiring autobiography, From Immigrant to Inventor. Pupin's creations included loading coils (extending the range of telephone lines) and a technique for reducing x-ray exposure time (making x-ray imaging safe for humans). Pupin was a pioneer in every sense of the word; it is reflected in his life story, straightforward writing style, and indomitable spirit.
Pupin's intellect quickly outgrew the place of his birth, the small Serbian village of Idvor in the Austrian Empire. So he was packed off to school in the nearby town of Panchevo. His new teachers, recognizing his potential, recommended that the fourteen-year old be sent to Prague. About one year later, Pupin decided he had outgrown Prague, selling most of his belongings (including his only coat) to buy a steerage-class ticket for New York City. He spent the next two weeks clinging to the ship's smokestack for warmth and arrived in America with just five cents in his pocket. After a series of menial jobs, he took the entrance exam for Columbia College at age 20, and earned free tuition. Pupin proved to be an outstanding student and athlete, and after graduating from Columbia he pursued further studies at the University of Cambridge and University of Berlin.
Pupin's idealism, more than anything else, made this a great book (he won the Pulitzer Prize for biography in 1924). Though confronted by much adversity, Pupin always saw the glass as half full. He believed that America was a land of opportunity, and his own life was a shining example. He studied not only science, but the great scientists. He defended America against European charges of crass materialism.
From Immigrant to Inventor reminds me in some ways of Laura Ingalls Wilder's Little House on the Prairie. Pupin tells his story in simple and direct language. He calmly and patiently describes the many hardships he faced--and how he overcame them. He offers a great deal of common sense, even when discussing science.
Unfortunately, the last chapter of Pupin's autobiography focuses on the National Research Council. Though he advocated a balance between pure research and applied science most of his life, in later years he seemed obsessed with big research. I liked Pupin better when he was defending American ingenuity and industry.
I recommend this book to all aspiring scientists, inventors, and entrepreneurs. It's as relevant today as it was in 1923.
Beware people deifying standards and open systems while villifying proprietary technologies. The pundits and press generally talk as if standards are always good and proprietary technologies are always bad. Actually, there is a time and place for each. If you don't think that's true, try making a list of the great inventions produced by standards committees. Good luck.
I'm not against voluntary standards and open systems. But I'm concerned about anything that inhibits innovation.
It's time to worry when groups start demanding the government enforce standards or open systems. Such groups always claim to represent the collective interests of consumers. Perhaps sometimes they do. Often they represent companies engaging in competition by other means.
A good example is Google's campaign last year to require 700-MHz spectrum bidders to meet its definition of "openness." Verizon Wireless' subsequent announcement that it is opening its network is not an admission that Google is right but a clever move to avert the threat of others dictating how Verizon must configure and operate its networks.
Google and its supporters argue that "openness" is needed to enable innovation. History says otherwise. Google's four essential open platform elements include applications, devices, services, and networks. Does anyone remember the Telecom Act of 1996 and the promised tsunami of competition? Google's four elements were all in place. Where are the Competitive Local Exchange Carriers (CLECs) today?
Fortunately, the FCC only adopted the first two open platform elements in its 700-Mhz rules. Verizon Wireless realized that the first two are acceptable as long as the operator remains in control of its network. Verizon concluded that the best way to retain control was to voluntarily open its network--showing that a forced march is unnecessary.
If there is one thing I learned researching my book, The History of Wireless, it's that researchers and inventors must remain free. That applies equally to big corporations, new ventures, and individuals.