|Cellular Phone Safety Questions Now Include Headsets|
By: Matthew E. Brunnworth
- Aegis Corporation
|Note: ||During January, 1998, Aegis was the first company to publicly address headset safety issues by informing its dealers and customers about the issues described in this White Paper.|
In April, 2000, the British consumer magazine, Which?, reported that hands-free kits for cellular phones do not reduce the amount of radio frequency radiation being absorbed by the brain as many people believe. They claimed the wire leading from the phone acted like an antenna and increased the amount of radiation penetrating the head by more than 300% when compared with placing a cellular phone against the ear. Although their test methods were inconsistent with current regulatory test procedures, newspapers worldwide published their findings.
In July, 2000, and in response to the Which? report, the British government commissioned an independent laboratory, SARTest, to perform a series of SAR (Specific Absorption Rate) tests that are consistent with current regulatory test procedures used worldwide to measure and define the safety of cellular phones. The validity of SAR test procedures as the criteria for determining cellular phone safety is being debated globally.
Using these procedures, SARTests reported a reduction in the amount of radiation penetrating the head when using a headset of 90%. On the basis of this report, the British government reported that hands-free kits reduce phone radiation exposure and advised consumers to use them as safety devices. A similar report released by Australian scientists reported a reduction of 70%.
Overall, these findings revealed a 390% variance.
Which? continued their investigations and commissioned another series of tests by the same laboratory that conducted their initial tests, ERA Technology LTD., in October, 2000, using five different phones and two different hands-free kits per phone. The test fixtures were presumably positioned in the way that most people would use a cellular phone and a hands-free kit: the phone positioned at or about waist level and the earpiece inserted in the ear with the wire hanging freely. First, measurements were taken with the phone handset next to the ear of a dummy head, and then taken again using a hands-free kit. During testing, the phones were moved up and down to vary the distance between the antenna mast and the earpiece. A follow up report released in November reported their findings that hands-free kits can reduce the amount of radiation penetrating the brain under a specific condition, however they can increase it by up to 350% under most conditions. They also reported why their findings were so different from SARTests and those of the government.
The critical factor
ERA’s laboratory took thousands of measurements to confirm the earlier test results and identify what was causing the differences. They stated the critical factor was that the wire of the hands-free kit served as an antenna and the distance between the phone’s antenna mast and the earpiece was a considerable factor for the amount of radiation traveling up the wire and emitted through the earpiece. At certain distances, there was a tuning effect that increased the electrical field at the headset’s earpiece.
The radiation levels for all 10 hands-free kits varied between distances of 40 and 80cm. There were two areas where the level of the signal at the ear was highest (from 40-47cm and again between 58-75cm), and one area where the level was lower (from 47-58cm). In positions where the levels were higher, they were between 46 - 259% higher than the phones themselves. In positions where the emissions were lower, the scale of the changes were between 8 - 97%.For many positions of a phone and hands-free kit worn in normal use, the tests detected higher emissions from the kits than when the phones were held against the head. The testing did reveal that while hands-free kits can reduce the emission levels in one position, they also significantly increase in all others tested.
The premise behind SAR is that if body tissue heats up beyond a certain level, it can be dangerous. This is frequently referred to as thermal level and using this approach as the sole criteria for determining the safety of cellular phones and headsets has significant shortcomings. First, there is irrefutable evidence that phone radiation affects protective biological mechanisms in the body far below what can be measured at the thermal level. Second, SAR does not consider long-term biological effects, but only observable behavioral effects induced in laboratory animals for the brief amount of time a phone or headset is tested. But perhaps the greatest testament that SAR standards should not be used is that none of the health disorders attributed to cellular phone radiation are thermally induced and all of them have a long incubation period.
SAR tests are based upon a calculated amount of energy that can safely be absorbed by the body, measuring energy in watts per kilogram that one gram of body tissue absorbs. It is calculated by measuring the maximum radio signal level inside the head and applying this value to a formula to calculate a SAR.
Tests are performed by inserting an electric-field test probe into a dummy head filled with a gel-like liquid that simulates the same electrical proprieties as brain tissue. In this case, it measures how much the brain heats up when a cellular phone is placed against the head and when a hands-free kit is used. Although in the process of being standardized as the method for rating radio frequency radiation from cellular phones, it is widely debated because it measures brain temperature increases after exposure for a brief amount of time, and not actual radiation emissions. This is one of the primary reasons why AegisGuard™ Radiation Shields were tested using ASTM test procedures instead of SAR.
Some scientists have concluded SAR levels are not the critical consideration because the radio frequency can be a far more damaging element than the amount of radiation absorbed. For example, a group of Spanish researchers released a report in late 1999 stating this method of calculating cellular phone emissions substantially underestimates their effects on human tissue.
SAR hands-free kit test limitations
To find out why the SAR tests showed hands-free kits reducing radiation levels being absorbed, Which? also employed the services of SARTests. Although the test procedures were similar to those used by ERA, they found differences in the way they were applied to testing hands-free kits. One consideration was the dummy head used at ERA’s facilities had an outer ear to accurately maintain a relative position for the phones and the hands-free kits; the test head at SARTest did not. An important difference was the SAR test fixture was on a wide platform that did not position the hands-free kit in the position most people would normally use. In fact, SAR measurements were taken with the phone lying on the platform, basically at shoulder height, with the wire coiled around or alongside of it. During testing, the wire was moved as much as possible and significantly increased SAR levels measured at the ear from the hands-free kits.
The most significant difference is that with the SAR test system, the probe scans the entire inside cavity of the dummy head and only provides a measurement for the area where the highest radiation level appears. With the kits, the highest emissions were at the ear; with the phones, it was at the jaw and cheek. ERA tested the phone and the hands-free kit earpiece at the same location, inside the head at ear level. Unlike ERA’s test, the SAR test system does not provide a reading for radiation emissions at the ear (close to the brain) for phones, only inside the dummy head.
Handle with care
Cellular phone radio waves are non-ionizing radiation. At high levels, such as those found in radar and microwave ovens, they can heat and severely damage living tissue. Similar to principle of mounting television antennas on rooftops, a phone transmits and receives better signals from head height than at waist level. According to phone manufacturers, hands-free equipment was designed for convenience, such as allowing writing or typing while listening to the phone and to reduce the possibility of accidents while driving. They were not designed to reduce radiation emissions.
The controversial issue is whether cellular phone radiation is dangerous to your health, and does the use of a hands-free kit increase or decrease that risk. Most people will attach the phone at the waist and connect a headset to it, causing the phone to increase it’s output power, which is an important consideration. This raises concern for unprotected body tissue at the waist level, such as the liver and kidneys, which have excellent conductivity and absorb radiation faster than the head due to a lack of surrounding bone. When a hands-free kit is attached to a cellular phone, electrical currents are conducted and induced on the wire, exposing internal organs and channeling the radiation more effectively through the ear piece.
What scientists know
For years, electromagnetic radiation has been suspected of causing a wide range of disorders, ranging from dizziness to genetic damage. Opinions differ between researchers on the effects of radio frequency radiation because of non-standardized testing procedures and materials. Traditionally, they have been separated into two categories: thermal (high energy) and non-thermal (low energy). Scientists understand the brain heats up when using a cellular phone, but the actual long-term biological effects of radio frequency radiation haven’t been determined, and they will not be determined for quite some time. Researchers worldwide are investigating non-thermal radiation to discover if there are ill-health effects, and there have been studies confirming effects upon the body far below what can be measured at the thermal level.
Medical researcher Dr. Bruce Hocking claims that cellular phones are likely to disturb nerve functions. He has reported a marked difference in the responsiveness of nerves behind, and just in front of, the ear after using of a cellular phone.
Swedish medical investigators conducted a two year study of patients with brain tumors. They concluded that cellular phone users of analog phones (the kind most commonly found in the U.S.) are at an increased risk of developing brain tumors, which are most likely to appear on the side of the head where users hold their phones.
Unlike analog phones however, digital phones use pulsed transmissions that some scientists believe are more dangerous.
Cellular phones may present a danger even when they are not in use. Dr. Roger Coghill, a British biologist, found that cellular phones on standby mode lowered the white blood cells to 10% of normal activity after exposure to radio frequency radiation.
A team of researchers in Spain claim the effects of cellular phone radiation could be 20% higher than previously thought. By studying more realistically shaped computer models of cells, they discovered electric fields are amplified across the cell membrane, a factor that had not been considered in other studies. It was also found that the angle of the cell in relation to the source of radiation is important, and that interactions between neighboring cells can significantly modify the electric field within each cell.
Researchers have discovered that electromagnetic radiation can cause subtle, short-term biological effects, including changes in brain wave patterns during sleep. Although cancer studies have so far been inconclusive, organizations including the National Cancer Institute and World Health Organization are investigating the issue. Many experts caution it’s too early to give cellular phones a clean bill of health, and it is important to understand that cancers represent a small number of the heath effects attributed to cellular phone radiation.
Change of heart
In December 2000, the British government reversed their endorsement advising consumers to use hands-free kits as a safety device that reduces cellular phone radiation exposure to the brain. The government sent out leaflets stating, “…The effectiveness of hands-free kits is uncertain”, and requested its citizen’s take a precautionary approach to cellular phones, particularly with children.
In May, 1995 and again in February, 2000, the FDA made no commitments concerning the effects of electromagnetic radio frequency radiation by saying “There is currently insufficient scientific basis for concluding either that wireless communication technologies are safe, or that they pose a risk to millions of users”.
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