By Adam Pierre
September 19, 2007
Persistent rumors suggest that Wi-Fi poses a threat to human health. Where there is smoke. . . law?
Around the world, fears persist about the potential health risks of Wi-Fi.
In recent reports, an Illinois school district shut down the installation of a Wi-Fi network in response to parents’ health concerns. The German government has warned against using Wi-Fi due to potential health risks. The president of a Canadian university has banned the use of Wi-Fi on campus for the same reason.
What is the risk, if any? Should the Wi-Fi industry be concerned about negative reactions from a health-conscious public?
We asked Dr Kenneth Foster, researcher at the Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania. His article, “Exposure to radio frequencies from wireless LANs,” appeared in the March 2007 issue of the journal Health physics.
Q: Does Wi-Fi pose a health risk?
A: I don’t see any evidence of that, nor do the major healthcare organizations around the world. There are dangers that may exist above certain levels of exposure to RF energy, so the United States sets limits well below those levels. In the case of Wi-Fi, there are very wide margins around any exposure considered potentially dangerous.
Q: Are we sure that these established limits negate all risks?
A: Human knowledge is not perfect, but this problem is not entirely new. People have been studying the possible health effects of radio frequency energy for generations now. In the current state of human knowledge, there is no convincing evidence of any risk.
Q: Scenario: I am using my laptop at Starbucks. What is my risk compared to other radio frequency activities?
A: The amount of energy emitted by the access points is very low. I did a survey of wireless LANs last year and in all cases the signal strength was minimal compared to other sources, such as cellular base stations. Most laptop client cards emit significantly less power than a cell phone.
At the same time, the interface speed is usually very high, but it transmits only in pulses, depending on system bottlenecks and handshake protocols. It is not a continuous transmission. So you are looking at an access point that has the power of a cell phone and only transmits for 1/1000e time. Exposure is therefore negligible compared to that from other sources.
Q: If these things are known, what causes the public concern?
A: Well, personally I am not afraid of this tiny source of radiation, when we live in a world surrounded by antennas, but other people may feel differently. It’s a social attitude. People react to possible risks in different ways. They may feel threatened by the technology itself, which may cause them to perceive health issues. It is not entirely a scientific question but rather a question of personal attitude towards risk.
People hear that there are still unanswered questions, and that scares them, which doesn’t always make sense. Is a bottle of Perrier safe? Personally, I have no problem. But is there any scientific evidence that there is no risk? Well, there is no such proof. There is no scientific proof that there is no danger in a Perrier bottle. But that doesn’t mean there are dangers.
Q: Have there been other cases of fear reaction to new technologies?
A: I have been in this business since 1971 and have heard the same stories and the same fears all this time. People have worried about broadcasting towers, military radar installations, video display terminals, power lines, and now it’s Wi-Fi, Bluetooth, cell phones. Each case is exactly the same. Public health officials have conducted examinations and have found no evidence of a problem, yet activists insist a terrible disaster could befall us. People raised the same question about light bulbs in the early 1900s.
Q: Governments and institutions around the world are warning of the risks of Wi-Fi and even discouraging its use. Should the industry feel threatened?
A: Most of our company has decided that they find Wi-Fi useful, so overall I don’t think it has much of an impact on the industry. If I were a Wi-Fi company, I would be a lot more concerned about the arrival of WiMAX and what it is going to do for the industry than I would be about it.Originally published on.