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Are cell phones harmful? Do cell phones cause cancer? These are questions we ask ourselves each time we hear the latest research results in the news, but we are still not sure if the answer is “Yes” or “No”. We’ve seen several documentaries about people suffering from brain tumors, saying that the main source of their illness is the large amount of time they have been exposed to cell phones radiation. The ones affected by this type of tumor used to talk on the phone maybe over 80% of the day time, as they were very busy people with high soliciting jobs, requiring many hours spent on talking and making important decisions from distance.



According to the American Cancer Society, the cell phone usage has spread worldwide since just 10 years, which is too short to be able to determine long-term health effects. During the last years, researchers have analyzed the differences between people affected by brain tumors that have been using cell phones, and those that are healthy and use the device. Results are unconcludent yet, but they seem to reveal the non-harmful side of the mobile phone use. Patients with brain cancer didn’t use the cell phones more often than the healthy ones, and intensive cell phone users do not show signs of this illness as it should if the radiation would be a cause for it. Also, these studies couldn’t link the side of the head with brain tumor with the side on which the mobile phone was used.



According to Wikipedia, until today there were several studies published including the following:



2004-The Danish study that took into consideration 10 years of cell phones use and found no sign revealing that humans can be affected by this type of radiation;
2005-The Swedish study showing that "the data do not support the hypothesis that mobile phone use is related to an increased risk of glioma or meningioma.";
2005-The British study concluding that "The study suggests that there is no substantial risk of acoustic neuroma in the first decade after starting mobile phone use. However, an increase in risk after longer term use or after a longer lag period could not be ruled out."
2006-The German study stating that "no overall increased risk of glioma or meningioma was observed among these cellular phone users; however, for long-term cellular phone users, results need to be confirmed before firm conclusions can be drawn.";
The INTERPHONE study conducted by Japan researchers who looked for brain tumor risks influenced by cell phones use. It tried to determine the SAR level inside tumors by calculating the RF level absorption in glioma, meninigioma, and pituitary adenoma. They didn’t find any proof to sustain the idea of cell phones use influencing tumor development.
Other studies, like Dr. Vini Khurana’s, showed that using cell phones more than 10 years doubles the risk of brain cancer, but it was highly criticized as there was no clear evidence.

Now if we take a look at the evolution of wireless safety standards, we’d realize that they have become stricter over time, which might suggest a possible concern over cell phone usage effects:
-1966: The ANSI C95.1 standard adopted the standard of 10mW/cm2 (10,000 μW/cm2) based on thermal effects.
-1982: The Institute of Electrical and Electronics Engineers recommended further lowering this limit to 1mW/cm2 (1,000 μW/cm2) for certain frequencies in 1982, which became a standard ten years later in 1992 (see below).
-1986: The National Council on Radiation Protection & Measurements recommended the exposure limit of 580 μW/cm2.
-1992: The ANSI/IEEE C95.1-1992 standard based on thermal effects used the 1mW/cm2 (1,000 μW/cm2) safety limit. The U.S. Environmental Protection Agency called this revised standard "seriously flawed", partly for failing to consider non-thermal effects, and called for the FCC to adopt the 1986 NCRP standard which was five times stricter.
-1996: The FCC updated to the standard of 580 μW/cm2 over any 30-minute period for the 869 MHz, while still using 1mW/cm2 (1,000 μW/cm2) for PCS frequencies (1850-1990 MHz).[59]
-1998: The ICNIRP standard uses the limit of 450 μW/cm2.
Not all cell phone models on the market spread the same amount of radiation. To find out about each model radiation level you should have to look for the Specific Absorption Rate level in the cell phone’s specifications, which shows the rate at which RF energy is absorbed by your body when exposed to the RF electromagnetic field.



Let’s clarify how this happens!
When you make a call the handset tries to contact the base station, also called cell phone tower, and this one responds with the same type of signals known as radio waves, so the enviroment is exposed to these waves circulating over the air. The antennas from the base stations have high power levels but the radio waves intensity is very low at the ground level , where you try to make the call.
To protect people from the RF radiation, the agencies responsible with public protection have set some standards: the exposure limit has to be in the range of 0.41-0.45 milliwatts per square centimeter, the power density inside buildings on top of which base stations are mounted is up to 100 times lower than the level outside because of special construction materials used, and as the power density behind the antennas is up to thousands of times lower than in front, the antenna are mounted on a side of the building.

But what about the cell phone towers?
When the cell phone communicates with the cell phone towers through radio waves, the energy consisting of photons sent in packages and measured in electron Volts doesn’t exceed one millionth of an eV, which is too small to be able to affect body molecules.
To cause cancer the radiation has to affect the body cells. Radio waves length is of 1 foot in the air and 2 inches in body tissue, which can’t be concentrated on small parts of tissue. Body cells are even smaller.
Another aspect is the magnitude of exposure, and tests showed that people are exposed at RF radiation related to cell phones at the same level as other sources like radios and television broadcast stations.
Also, not all of you are aware of the fact that when the cell phone has a high signal strength the power output is 1000 times lower than when the signal is poor.



Back to the SAR. The Specific Absorption Rate is calculated on 1 gram or 10 grams of tissue, and measures the exposure in fields between 100kHz and 10 GHz.
Governments that took measures against this possible problem set clear SAR limits, such as the United States that requires the SAR to be below 1.6 W/Kg in 1 gram of tissue, or the European Union that asks for maximum 2 W/Kg at 10 grams of tissue, with 0.08 W/Kg average exposure over the whole body.
These are the methods you can reduce your exposure to the radiation when using cell phones: call only when you need, make only short calls, send text messages as often as possible, don’t use your cell phone when the signal strength is low, use the phone outside or close to a window, switch off the phone when not in use.

To give you a few examples of the latest cell phone models’ SAR levels, Nokia E51 has 1.47 W/kg, Nokia N95 has 0.50 W/kg, Samsung Instinct has 1.16 W/kg for the head and 1.220 W/kg for the body, Sony Ericsson C902 has 1.32 W/Kg, and Motorola MOTO W755 has 0.8 W/Kg.

(Sources: Mobile Phones UK; Wikipedia; American Cancer Society)