Earlier this week, the World Health Organization (WHO) released a report on the possible carcinogenic effects of cell phones, thereby triggering interest about which cell phones emit the least radiation.

Cell phones emit radio waves, called radiofrequency (RF), which is a form of radiation. The phones themselves aren't necessarily harmful. It's the radiation emitted by the phones that's harmful and more importantly, the amount of radiation that your body absorbs. Specific absorption rate (SAR) is the name given to the rate of radiofrequency energy your body gets from continuous phone usage. The lower the number, the lower the radiation exposure.

However, besides SAR, many other factors can affect the amount of RF waves to which a person is exposed.

American Cancer Society gives specific examples about other causes:

- The amount of time the person is on the phone
- The model of phone being used: different phones give off different amounts of energy
- Whether or not the person is using a hands-free device
- The distance and path to the nearest cell phone tower: being farther away from the tower requires more energy to get a good signal, as does being inside a building
- The amount of cell phone traffic in the area at the time

Other factors may include the distance from the phone to your body. The closer the antenna is to the head, the greater a person's expected exposure to RF energy. Older cell phones, especially analog phones, use more energy than newer digital models.

While there is no decisive evidence that a phone with a higher SAR level poses a greater health risk, consumers are now checking SAR levels before purchasing a new phone in order to reduce radiation exposures.

The Environmental Working Group has compiled a list of major cell phones which measure the SAR levels based on phone manufacturers data from December 2010.

Click on the slideshow to check out the top 10 lowest radiation emitting cell phone models:

 Note that the Federal Communications Commission (FCC) requires all cell phone makers to report the SAR level of their products and its maximum SAR level must be less than 1.6 watts per kilogram (W/kg).

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