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« Clinton: Support Broadband Where Unprofitable | Main | Strix Adds Voice over WLAN to Bangladesh »

February 22, 2006

Canadian University Says Wi-Fi Networks Might Pose Health Risk

The head of the university has the right motives, but the wrong science: Lakehead University president Fred Gilbert should probably consult with the physics department (and any epidemiologists on staff) before making a decision like this in the future. He cites a variety of studies that involve enormously higher and more focused electromagnetic radiation and which still produce no conclusive results that point to elevated risks of cancer or other diseases.

I support his notion of prudence, but unless he bans cell phones and nearby cell towers, cordless 2.4 GHz phones, and other microwave emitters that produce higher amounts of microwave output, it's a little silly to focus on the low-power, diffuse, hard-to-tell-apart-from-noise nature of Wi-Fi.

It's hard to ridicule the guy, though, because he's not asserting anything factually incorrect nor is he grandstanding. It's apparent he has the best interests of students and staff at heart, and that should only be commended. [Link via BoingBoing]

Update: I take back the part about not him not asserting factually incorrect statements. Reuters quotes his statement as being, "Some studies have indicated that there are links to carcinogenetic occurrences in animals, including humans, that are related to energy fields associated with wireless hotspots, whether those hotspots are transmissions lines, whether they're outlets, plasma screens, or microwave ovens that leak."

This is extremely sloppy: wireless hotspots aren't a large category that includes transmission lines, power outlets, screen, and microwave ovens. The president's background is in biology and zoology, not comparative literature or interpretative dance, and thus one might expect that a rigorous scientific grounding would inform his public statements.

That's a bad trope on microwave ovens, by the way. They produce a high-intensity beam that dissipates very quickly; it's only reflection within the oven that causes water molecules to twist, heating the food. Thus even a large leak would only have an effect if you were very close, and then very little (unless it was a massive hole) because the beam is moving to produce even food coverage. Can someone teach the rest of the world the inverse square rule?


Don't forget about televisions, radios, wireless keyboards/mice, etc. Any CRT monitor. There are all sorts of emissions in our every day life. I mentioned cell towers in my post too, but I'm a lot more cynical than you, Glenn. *laugh*

Take care.

A microwave oven's radiation is well contained, even though some leakage exists but it's not on 24 hours a day and I don't have to stand near it when it is on.

A chemistry professor at U. of Oregon- Paul C. Engelking, also raised concerns about wi-fi, but for other reasons like students surfing the net while they should be paying attention in class. He caught my attention when he pointed out a possible scenario in which a large lecture hall filled with 300-500 laptops connecting to the wi-fi. With 100 mW output from each laptop, the aggregate radiated power can add up quickly to range betwen 30 and 50 W. The radiation from my own laptop, or that of the wi-fi access point would probably not bother me as much as the combined radiation from the other possible 459 in a confined space like a lecture hall.

[Editor's note: That's not correct. Hundreds of laptops are each their own radiator and each have significant signal dropoff with the inverse square of the distance from the source. So having 100 30 mW radiators isn't like having 30 W of radiation in a space, even with reflection.--gf]

I appreciate that the inverse square law would mean laptops located farther away are going to contribute insignficant amount of radiation to my incremental exposure. Instead of the 300-500 times incremental exposure, I might only experience a triple or quadruple amount of exposure mostly attributed to the laptops in my immediate vicinity.

These levels are probably still benign, but do we really know where "benign level" begins and stops?

[Editor's note: Not 3 or 4 times as much: Even if you're surrounding by 8 laptops as the center of a square, you're probably getting no more than 20 or 30 percent higher emission exposure than your own device. Inverse square means signal strength drops very rapidly. To get the maximum signal exposure, everyone would have to be streaming at full speed all around you, too. Wi-Fi is burst just like Internet access in general is bursty: mostly empty with moments of usage.

Empirically, lots is known: the FCC and other groups have been studying exposure to microwave radiation (electromagnetic radiation in the range that covers all radio communication) for decades. That doesn't mean there aren't emergent properties, nor special cases because of the closeness of newer emitters to our laps or heads.

Generally, though, you can predict based on the amount of energy in a signal (through measurement or theory) how much excitation will be provoked and by what kinds of molecules. --gf]