用手提電話過長時間或太多會對腦部有什麼影響及後果?(請用英文回答)

Effects of mobile telephone radiation

So far, the only known mechanism that mobile telephone radiation has had an effect on living tissue is heating. The rise in temperature on the surface of the brain caused by radio waves is 0.3 degrees at the most. This kind of temperature rise is not known to have biological significance. The temperature of the brain normally fluctuates by about one degree, and only after a five degree increase in temperature do cells become damaged.

Several studies, in several countries, have tried to find out any other effects apart from heating. On the basis of the results obtained from the studies, it has not been possible to conclude that radiation from mobile phones would be detrimental to health.

Experiments performed on cell cultures, also performed at STUK, have produced indicators that mobile telephone radiation could cause temporary changes in the functions of cells. These functions include the functions of genes, activation of proteins, and the internal chemical communication within cells. The trigger for these changes is unknown. It is only known that this phenomenon is not the result of excessive heating of tissue.

Radio waves at the radiation level of mobile phones may increase the permeability of the so-called blood-brain barrier. The blood-brain barrier regulates the passing of material between the bloodstream and brain cells. Possible changes are, however, minimal and disappear quickly when the radiation stops. This could possibly be a case of a change caused by microscopic heating. The occurrence falls within the realm of physiological fluctuation and is not known to be harmful.

Mobile phone radiation and health concerns have been raised, especially following the enormous increase in the use of wireless mobile telephony throughout the world (as of August 2005, there were more than 2 billion users worldwide). This is because mobile phones use electromagnetic waves in the microwave range. These concerns have induced a large body of research (both epidemiological and experimental, in non-human animals as well as in humans). Concerns about effects on health have also been raised regarding other digital wireless systems, such as data communication networks.

The World Health Organization has officially ruled out adverse health effects from cellular base stations and wireless data networks, and expects to make recommendations about mobile phones in 2007-08 .

However, some National Radiation Protection Authorities, i.e. Austria Germanyand Sweden,recommends their citizens to minimize radiation. Examples of recommendations are:

* Use hands-free to decrease the radiation to the head
* Keep the mobile phone away from the body.
* Do not telephone in a car without an external antenna.