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lördag 5 april 2008

Dangers of radiation in the home

The best Swedish site for news on technology, in my opinion, is www.idg.se. Today they have an article on radiation in the home. The article is based on an interview with Maria Feychting professor in epidemiology at Karolinska Institutet. The article discusses the danger of the radiation associated with products that are becomming increasingly common in ordinary homes. I am speaking of mobile phones, routers, wireless keyboards and mice, bluetooth headsets and dect phones.

The conclusion of the article, briefly put, is that there are no scientific evidence that this radiation causes any harm. It is a fact that studies showing potential dangers of radiation get much more attention than studies which show zero effects, even though the latter type are much more common. Furthermore, most of the studies which have shown slight biological effects of radiation have subsequently been replicated with contrasting results i.e. the latter studies did not find any effects.

I think that one of the reasons why some people are so afraid of these things is the fact that they radiate, and we all know that radiation is bad right? No, not necessarily so. Radiation can be your friend to. If it were not for the radiation from the sun we would not be alive. Similarly, seeing involves the capture of radiation by photoreceptors in the back of your retina. In fact we are all rich sources of radiation which you can see for yourself if you have a camera that pick up infrared wavelength.


But isn't that different? Sure some sorts of radiation are more dangerous than others. Cosmic rays which arive from outer space are extremely rich in energy, and alot of that type of radiation would be bad for you. Similarly, X-rays will slightly increase the risk of cancers because it is rich in energy. But what about the radiation from all those home devices? This radiation is lower in energy than normal visual light, so you are very unlikely to get cancer from this type of radiation. These devices actually emit microwaves, just like your microwave oven. The difference is that the radiation is not contained within a box, and also the power is 10,000 smaller than in an ordinary microwave oven (for a dect phone it is 100,000 times smaller). If you want a different point of view on these issues, you can visit this page.

The article also gives some quick answers to the following questions:

1. Does radiation from mobile phones cause cancer: False

2. Will using a bluetooth headset reduce the amount of radiation you are exposed to: True (because a bluetooth headset has a much lower effect than the mobile phone)

3. A dect phone emits more radiation than a mobile phone: False

4. A 3G phone radiates more than a GSM mobile phone: False

5. More wireless devices in the home will make it more dangerous: False

6. A new router radiates more than an old router: False

7. It is dangerous to have your mobile lying next to you when you are sleeping: False

8. The mobile will emit less radiation if you hold your hand over it: False (actually it will radiate more becuase that is necessary in order to communicate the station.

9. Even the good old cable hardware emits radiation: True (anything with a current in it, a cable for instance, will generate a magnetic field which is also basically a form of radiation.


I want to end with a personal reflection on an issue which I think is highly relevant yet often forgotten. Mobile phones, which as mentioned is the device which has the highest effect and thus the highest radiation, has been around for about two decades now. In spite of their popularity, there has not been any increase in cancers in this timeperiod. This "natural experiment" shows that if mobile phones have any effect at all on the human body, that effect have to be very subtle. Pretend for a moment that there has been a slight increase in some obscure form of cancer, or other type of disease, that is a result of mobile phone radiation. Even such a necessarily slight effect would pale in comparison to the enourmous benefits of being able to call ambulances, fire fighters and the police from almost anywhere on this planet. Hurray for mobile phones!

tisdag 31 juli 2007

Irrational fear 2: Nuclear power


Last time I wrote about pesticides and how we are worried to death about 0.01% of the pesticides that we ingest (the synthetic ones) instead of the 99% which seem to be as bad if not worse. Another area which I think is often associated with irrational fear is nuclear power. The word "nuclear" seems to elicit a knee-jerk kind of reaction in many people. Take for instance Nuclear Magnetic Resonance imaging (NMR for short), a very powerful and quite safe diagnostic method. People were very reluctant to use this method, seemingly only because it had "Nuclear" in the name. In part because of this fear they have now changed the name to Magnetic Resonace Imaging (MRI for short), and the technology has been a major boost to diagnostics as well as to research.


The following arguments are to a large extent a reflection on Richard Muller's (see picture below) paper with the title "The witch of Yucca Mountain". I can warmly recommend the article but if you want the same information in video format you can go here and forward to 47min and listen to the rest of the lecture (it is very entertaining).


It is no secret that we are facing an energy crisis. I am personally not convinced that CO2 emissions is an important contributing factor when it comes to Global warming, however, the fact of the matter is that our fossil fuels will eventually be used up and when there is none left we will need a different source of energy. Fission of uranium and plutonium is not an endless source of energy, however, it would provide us with energy for quite a while. Yet many countries do not want to build these Nuclear power plants, largely because of what I think is irrational fear…


Before I encountered Muller I associated nuclear power plant accidents with Chernobyl (see picture). However, Chernobyl was not a typical nuclear power plant. Its design was the worst imaginable and as Muller explains in his lecture such a design is completely prohibited today. The worst case scenario for a modern nuclear power plant is the nuclear meltdown. For a meltdown to occur, it is required that 4 different independent security systems which are inspected regularly, break down simultaneously which is not at all likely. If however, the highly unlikely worst case scenario would occur, and the radioactive material would penetrate meters of steel and concrete and go into the ground and the gases escape we would still not have anywhere near the same levels of radioactivity that were present after Chernobyl because the radioactivity leaks out into the ground instead of being blown up into the sky. I can understand that people want Nuclear Powerplants to be safe, however, there seems to be some sort of obsession here. People seem not to worry about other types of dangers. What if a chemical plant blew up? What is the worst case scenario there? Or what about the laboratories where they deal with the Ebola virus, what would happen if all their security systems broke down?



There is also a major concern about nuclear waste. The plutonium waste coming from a nuclear power plant has a half life of about 24.000 years meaning that after 96.000 years 1/16 of the radioactive waste will still remain. The question which does not yet have an answer is, where are we going to store this waste? In United States, Yucca Mountain, a place with very few earthquakes, was chosen as an ideal storage site. If the unthinkable would happen at Yucca Mountain, and all the radioactive waste would leak out, it would still be in small non-water soluble glass-pellets, so it would not mix with the ground water. Furthermore, even if Yucca Mountain was filled to its capacity limit and all the radioactive waste leaked out into the ground water and then out of the pellets in which it is cotained (this scenario has already passed into science fiction), the water would still not reach even a fraction of the radioactivity levels present in the Los Angeles drinking water! The drinking water that the citizens of Los Angeles are drinking is from the Colorado river which flows through many valleys with Granite. Granite contains some fraction of percentage of uranium which is slowly dissolved in the drinking water, thus making it radioactive. Because there is no agreement on where to store the waste today, today the radioactive material is simply sitting in a building next to the nuclear plant, not an ideal storage site.

To sum up, instead of storing the nuclear waste in the safest imaginable location where it has virtually no chance of leaking out, and even if it would leak out it would not be a major disaster, it is stored in buildings next to the power plants, which is a much less safe location, all because of the irrational fear among the public.